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Diffstat (limited to 'sys-kernel/linux-sources-redcore-lts-legacy/files/4.19-0001-MultiQueue-Skiplist-Scheduler-version-v0.180-linux-hardened.patch')
| -rw-r--r-- | sys-kernel/linux-sources-redcore-lts-legacy/files/4.19-0001-MultiQueue-Skiplist-Scheduler-version-v0.180-linux-hardened.patch | 10305 |
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diff --git a/sys-kernel/linux-sources-redcore-lts-legacy/files/4.19-0001-MultiQueue-Skiplist-Scheduler-version-v0.180-linux-hardened.patch b/sys-kernel/linux-sources-redcore-lts-legacy/files/4.19-0001-MultiQueue-Skiplist-Scheduler-version-v0.180-linux-hardened.patch new file mode 100644 index 00000000..ee298f6a --- /dev/null +++ b/sys-kernel/linux-sources-redcore-lts-legacy/files/4.19-0001-MultiQueue-Skiplist-Scheduler-version-v0.180-linux-hardened.patch @@ -0,0 +1,10305 @@ +diff -Nur a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c +--- a/arch/powerpc/platforms/cell/spufs/sched.c 2019-02-06 16:30:16.000000000 +0000 ++++ b/arch/powerpc/platforms/cell/spufs/sched.c 2019-02-09 17:46:11.991297545 +0000 +@@ -65,11 +65,6 @@ + static struct timer_list spuloadavg_timer; + + /* +- * Priority of a normal, non-rt, non-niced'd process (aka nice level 0). +- */ +-#define NORMAL_PRIO 120 +- +-/* + * Frequency of the spu scheduler tick. By default we do one SPU scheduler + * tick for every 10 CPU scheduler ticks. + */ +diff -Nur a/arch/x86/Kconfig b/arch/x86/Kconfig +--- a/arch/x86/Kconfig 2019-02-09 17:20:30.461820549 +0000 ++++ b/arch/x86/Kconfig 2019-02-09 17:51:10.780941815 +0000 +@@ -1003,6 +1003,20 @@ + config SCHED_SMT + def_bool y if SMP + ++config SMT_NICE ++ bool "SMT (Hyperthreading) aware nice priority and policy support" ++ depends on SCHED_MUQSS && SCHED_SMT ++ default y ++ ---help--- ++ Enabling Hyperthreading on Intel CPUs decreases the effectiveness ++ of the use of 'nice' levels and different scheduling policies ++ (e.g. realtime) due to sharing of CPU power between hyperthreads. ++ SMT nice support makes each logical CPU aware of what is running on ++ its hyperthread siblings, maintaining appropriate distribution of ++ CPU according to nice levels and scheduling policies at the expense ++ of slightly increased overhead. ++ If unsure say Y here. ++ + config SCHED_MC + def_bool y + prompt "Multi-core scheduler support" +@@ -1033,6 +1047,80 @@ + + If unsure say Y here. + ++choice ++ prompt "CPU scheduler runqueue sharing" ++ default RQ_MC if SCHED_MUQSS ++ default RQ_NONE ++ ++config RQ_NONE ++ bool "No sharing" ++ help ++ This is the default behaviour where the CPU scheduler has one runqueue ++ per CPU, whether it is a physical or logical CPU (hyperthread). ++ ++ This can still be enabled runtime with the boot parameter ++ rqshare=none ++ ++ If unsure, say N. ++ ++config RQ_SMT ++ bool "SMT (hyperthread) siblings" ++ depends on SCHED_SMT && SCHED_MUQSS ++ ++ help ++ With this option enabled, the CPU scheduler will have one runqueue ++ shared by SMT (hyperthread) siblings. As these logical cores share ++ one physical core, sharing the runqueue resource can lead to decreased ++ overhead, lower latency and higher throughput. ++ ++ This can still be enabled runtime with the boot parameter ++ rqshare=smt ++ ++ If unsure, say N. ++ ++config RQ_MC ++ bool "Multicore siblings" ++ depends on SCHED_MC && SCHED_MUQSS ++ help ++ With this option enabled, the CPU scheduler will have one runqueue ++ shared by multicore siblings in addition to any SMT siblings. ++ As these physical cores share caches, sharing the runqueue resource ++ will lead to lower latency, but its effects on overhead and throughput ++ are less predictable. As a general rule, 6 or fewer cores will likely ++ benefit from this, while larger CPUs will only derive a latency ++ benefit. If your workloads are primarily single threaded, this will ++ possibly worsen throughput. If you are only concerned about latency ++ then enable this regardless of how many cores you have. ++ ++ This can still be enabled runtime with the boot parameter ++ rqshare=mc ++ ++ If unsure, say Y. ++ ++config RQ_SMP ++ bool "Symmetric Multi-Processing" ++ depends on SMP && SCHED_MUQSS ++ help ++ With this option enabled, the CPU scheduler will have one runqueue ++ shared by all physical CPUs unless they are on separate NUMA nodes. ++ As physical CPUs usually do not share resources, sharing the runqueue ++ will normally worsen throughput but improve latency. If you only ++ care about latency enable this. ++ ++ This can still be enabled runtime with the boot parameter ++ rqshare=smp ++ ++ If unsure, say N. ++endchoice ++ ++config SHARERQ ++ int ++ default 0 if RQ_NONE ++ default 1 if RQ_SMT ++ default 2 if RQ_MC ++ default 3 if RQ_SMP ++ ++ + config UP_LATE_INIT + def_bool y + depends on !SMP && X86_LOCAL_APIC +diff -Nur a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt +--- a/Documentation/admin-guide/kernel-parameters.txt 2019-02-09 17:20:30.451820228 +0000 ++++ b/Documentation/admin-guide/kernel-parameters.txt 2019-02-09 17:46:11.981297222 +0000 +@@ -4003,6 +4003,14 @@ + Memory area to be used by remote processor image, + managed by CMA. + ++ rqshare= [X86] Select the MuQSS scheduler runqueue sharing type. ++ Format: <string> ++ smt -- Share SMT (hyperthread) sibling runqueues ++ mc -- Share MC (multicore) sibling runqueues ++ smp -- Share SMP runqueues ++ none -- So not share any runqueues ++ Default value is mc ++ + rw [KNL] Mount root device read-write on boot + + S [KNL] Run init in single mode +diff -Nur a/Documentation/scheduler/sched-BFS.txt b/Documentation/scheduler/sched-BFS.txt +--- a/Documentation/scheduler/sched-BFS.txt 1970-01-01 01:00:00.000000000 +0100 ++++ b/Documentation/scheduler/sched-BFS.txt 2019-02-09 17:46:11.981297222 +0000 +@@ -0,0 +1,351 @@ ++BFS - The Brain Fuck Scheduler by Con Kolivas. ++ ++Goals. ++ ++The goal of the Brain Fuck Scheduler, referred to as BFS from here on, is to ++completely do away with the complex designs of the past for the cpu process ++scheduler and instead implement one that is very simple in basic design. ++The main focus of BFS is to achieve excellent desktop interactivity and ++responsiveness without heuristics and tuning knobs that are difficult to ++understand, impossible to model and predict the effect of, and when tuned to ++one workload cause massive detriment to another. ++ ++ ++Design summary. ++ ++BFS is best described as a single runqueue, O(n) lookup, earliest effective ++virtual deadline first design, loosely based on EEVDF (earliest eligible virtual ++deadline first) and my previous Staircase Deadline scheduler. Each component ++shall be described in order to understand the significance of, and reasoning for ++it. The codebase when the first stable version was released was approximately ++9000 lines less code than the existing mainline linux kernel scheduler (in ++2.6.31). This does not even take into account the removal of documentation and ++the cgroups code that is not used. ++ ++Design reasoning. ++ ++The single runqueue refers to the queued but not running processes for the ++entire system, regardless of the number of CPUs. The reason for going back to ++a single runqueue design is that once multiple runqueues are introduced, ++per-CPU or otherwise, there will be complex interactions as each runqueue will ++be responsible for the scheduling latency and fairness of the tasks only on its ++own runqueue, and to achieve fairness and low latency across multiple CPUs, any ++advantage in throughput of having CPU local tasks causes other disadvantages. ++This is due to requiring a very complex balancing system to at best achieve some ++semblance of fairness across CPUs and can only maintain relatively low latency ++for tasks bound to the same CPUs, not across them. To increase said fairness ++and latency across CPUs, the advantage of local runqueue locking, which makes ++for better scalability, is lost due to having to grab multiple locks. ++ ++A significant feature of BFS is that all accounting is done purely based on CPU ++used and nowhere is sleep time used in any way to determine entitlement or ++interactivity. Interactivity "estimators" that use some kind of sleep/run ++algorithm are doomed to fail to detect all interactive tasks, and to falsely tag ++tasks that aren't interactive as being so. The reason for this is that it is ++close to impossible to determine that when a task is sleeping, whether it is ++doing it voluntarily, as in a userspace application waiting for input in the ++form of a mouse click or otherwise, or involuntarily, because it is waiting for ++another thread, process, I/O, kernel activity or whatever. Thus, such an ++estimator will introduce corner cases, and more heuristics will be required to ++cope with those corner cases, introducing more corner cases and failed ++interactivity detection and so on. Interactivity in BFS is built into the design ++by virtue of the fact that tasks that are waking up have not used up their quota ++of CPU time, and have earlier effective deadlines, thereby making it very likely ++they will preempt any CPU bound task of equivalent nice level. See below for ++more information on the virtual deadline mechanism. Even if they do not preempt ++a running task, because the rr interval is guaranteed to have a bound upper ++limit on how long a task will wait for, it will be scheduled within a timeframe ++that will not cause visible interface jitter. ++ ++ ++Design details. ++ ++Task insertion. ++ ++BFS inserts tasks into each relevant queue as an O(1) insertion into a double ++linked list. On insertion, *every* running queue is checked to see if the newly ++queued task can run on any idle queue, or preempt the lowest running task on the ++system. This is how the cross-CPU scheduling of BFS achieves significantly lower ++latency per extra CPU the system has. In this case the lookup is, in the worst ++case scenario, O(n) where n is the number of CPUs on the system. ++ ++Data protection. ++ ++BFS has one single lock protecting the process local data of every task in the ++global queue. Thus every insertion, removal and modification of task data in the ++global runqueue needs to grab the global lock. However, once a task is taken by ++a CPU, the CPU has its own local data copy of the running process' accounting ++information which only that CPU accesses and modifies (such as during a ++timer tick) thus allowing the accounting data to be updated lockless. Once a ++CPU has taken a task to run, it removes it from the global queue. Thus the ++global queue only ever has, at most, ++ ++ (number of tasks requesting cpu time) - (number of logical CPUs) + 1 ++ ++tasks in the global queue. This value is relevant for the time taken to look up ++tasks during scheduling. This will increase if many tasks with CPU affinity set ++in their policy to limit which CPUs they're allowed to run on if they outnumber ++the number of CPUs. The +1 is because when rescheduling a task, the CPU's ++currently running task is put back on the queue. Lookup will be described after ++the virtual deadline mechanism is explained. ++ ++Virtual deadline. ++ ++The key to achieving low latency, scheduling fairness, and "nice level" ++distribution in BFS is entirely in the virtual deadline mechanism. The one ++tunable in BFS is the rr_interval, or "round robin interval". This is the ++maximum time two SCHED_OTHER (or SCHED_NORMAL, the common scheduling policy) ++tasks of the same nice level will be running for, or looking at it the other ++way around, the longest duration two tasks of the same nice level will be ++delayed for. When a task requests cpu time, it is given a quota (time_slice) ++equal to the rr_interval and a virtual deadline. The virtual deadline is ++offset from the current time in jiffies by this equation: ++ ++ jiffies + (prio_ratio * rr_interval) ++ ++The prio_ratio is determined as a ratio compared to the baseline of nice -20 ++and increases by 10% per nice level. The deadline is a virtual one only in that ++no guarantee is placed that a task will actually be scheduled by this time, but ++it is used to compare which task should go next. There are three components to ++how a task is next chosen. First is time_slice expiration. If a task runs out ++of its time_slice, it is descheduled, the time_slice is refilled, and the ++deadline reset to that formula above. Second is sleep, where a task no longer ++is requesting CPU for whatever reason. The time_slice and deadline are _not_ ++adjusted in this case and are just carried over for when the task is next ++scheduled. Third is preemption, and that is when a newly waking task is deemed ++higher priority than a currently running task on any cpu by virtue of the fact ++that it has an earlier virtual deadline than the currently running task. The ++earlier deadline is the key to which task is next chosen for the first and ++second cases. Once a task is descheduled, it is put back on the queue, and an ++O(n) lookup of all queued-but-not-running tasks is done to determine which has ++the earliest deadline and that task is chosen to receive CPU next. ++ ++The CPU proportion of different nice tasks works out to be approximately the ++ ++ (prio_ratio difference)^2 ++ ++The reason it is squared is that a task's deadline does not change while it is ++running unless it runs out of time_slice. Thus, even if the time actually ++passes the deadline of another task that is queued, it will not get CPU time ++unless the current running task deschedules, and the time "base" (jiffies) is ++constantly moving. ++ ++Task lookup. ++ ++BFS has 103 priority queues. 100 of these are dedicated to the static priority ++of realtime tasks, and the remaining 3 are, in order of best to worst priority, ++SCHED_ISO (isochronous), SCHED_NORMAL, and SCHED_IDLEPRIO (idle priority ++scheduling). When a task of these priorities is queued, a bitmap of running ++priorities is set showing which of these priorities has tasks waiting for CPU ++time. When a CPU is made to reschedule, the lookup for the next task to get ++CPU time is performed in the following way: ++ ++First the bitmap is checked to see what static priority tasks are queued. If ++any realtime priorities are found, the corresponding queue is checked and the ++first task listed there is taken (provided CPU affinity is suitable) and lookup ++is complete. If the priority corresponds to a SCHED_ISO task, they are also ++taken in FIFO order (as they behave like SCHED_RR). If the priority corresponds ++to either SCHED_NORMAL or SCHED_IDLEPRIO, then the lookup becomes O(n). At this ++stage, every task in the runlist that corresponds to that priority is checked ++to see which has the earliest set deadline, and (provided it has suitable CPU ++affinity) it is taken off the runqueue and given the CPU. If a task has an ++expired deadline, it is taken and the rest of the lookup aborted (as they are ++chosen in FIFO order). ++ ++Thus, the lookup is O(n) in the worst case only, where n is as described ++earlier, as tasks may be chosen before the whole task list is looked over. ++ ++ ++Scalability. ++ ++The major limitations of BFS will be that of scalability, as the separate ++runqueue designs will have less lock contention as the number of CPUs rises. ++However they do not scale linearly even with separate runqueues as multiple ++runqueues will need to be locked concurrently on such designs to be able to ++achieve fair CPU balancing, to try and achieve some sort of nice-level fairness ++across CPUs, and to achieve low enough latency for tasks on a busy CPU when ++other CPUs would be more suited. BFS has the advantage that it requires no ++balancing algorithm whatsoever, as balancing occurs by proxy simply because ++all CPUs draw off the global runqueue, in priority and deadline order. Despite ++the fact that scalability is _not_ the prime concern of BFS, it both shows very ++good scalability to smaller numbers of CPUs and is likely a more scalable design ++at these numbers of CPUs. ++ ++It also has some very low overhead scalability features built into the design ++when it has been deemed their overhead is so marginal that they're worth adding. ++The first is the local copy of the running process' data to the CPU it's running ++on to allow that data to be updated lockless where possible. Then there is ++deference paid to the last CPU a task was running on, by trying that CPU first ++when looking for an idle CPU to use the next time it's scheduled. Finally there ++is the notion of cache locality beyond the last running CPU. The sched_domains ++information is used to determine the relative virtual "cache distance" that ++other CPUs have from the last CPU a task was running on. CPUs with shared ++caches, such as SMT siblings, or multicore CPUs with shared caches, are treated ++as cache local. CPUs without shared caches are treated as not cache local, and ++CPUs on different NUMA nodes are treated as very distant. This "relative cache ++distance" is used by modifying the virtual deadline value when doing lookups. ++Effectively, the deadline is unaltered between "cache local" CPUs, doubled for ++"cache distant" CPUs, and quadrupled for "very distant" CPUs. The reasoning ++behind the doubling of deadlines is as follows. The real cost of migrating a ++task from one CPU to another is entirely dependant on the cache footprint of ++the task, how cache intensive the task is, how long it's been running on that ++CPU to take up the bulk of its cache, how big the CPU cache is, how fast and ++how layered the CPU cache is, how fast a context switch is... and so on. In ++other words, it's close to random in the real world where we do more than just ++one sole workload. The only thing we can be sure of is that it's not free. So ++BFS uses the principle that an idle CPU is a wasted CPU and utilising idle CPUs ++is more important than cache locality, and cache locality only plays a part ++after that. Doubling the effective deadline is based on the premise that the ++"cache local" CPUs will tend to work on the same tasks up to double the number ++of cache local CPUs, and once the workload is beyond that amount, it is likely ++that none of the tasks are cache warm anywhere anyway. The quadrupling for NUMA ++is a value I pulled out of my arse. ++ ++When choosing an idle CPU for a waking task, the cache locality is determined ++according to where the task last ran and then idle CPUs are ranked from best ++to worst to choose the most suitable idle CPU based on cache locality, NUMA ++node locality and hyperthread sibling business. They are chosen in the ++following preference (if idle): ++ ++* Same core, idle or busy cache, idle threads ++* Other core, same cache, idle or busy cache, idle threads. ++* Same node, other CPU, idle cache, idle threads. ++* Same node, other CPU, busy cache, idle threads. ++* Same core, busy threads. ++* Other core, same cache, busy threads. ++* Same node, other CPU, busy threads. ++* Other node, other CPU, idle cache, idle threads. ++* Other node, other CPU, busy cache, idle threads. ++* Other node, other CPU, busy threads. ++ ++This shows the SMT or "hyperthread" awareness in the design as well which will ++choose a real idle core first before a logical SMT sibling which already has ++tasks on the physical CPU. ++ ++Early benchmarking of BFS suggested scalability dropped off at the 16 CPU mark. ++However this benchmarking was performed on an earlier design that was far less ++scalable than the current one so it's hard to know how scalable it is in terms ++of both CPUs (due to the global runqueue) and heavily loaded machines (due to ++O(n) lookup) at this stage. Note that in terms of scalability, the number of ++_logical_ CPUs matters, not the number of _physical_ CPUs. Thus, a dual (2x) ++quad core (4X) hyperthreaded (2X) machine is effectively a 16X. Newer benchmark ++results are very promising indeed, without needing to tweak any knobs, features ++or options. Benchmark contributions are most welcome. ++ ++ ++Features ++ ++As the initial prime target audience for BFS was the average desktop user, it ++was designed to not need tweaking, tuning or have features set to obtain benefit ++from it. Thus the number of knobs and features has been kept to an absolute ++minimum and should not require extra user input for the vast majority of cases. ++There are precisely 2 tunables, and 2 extra scheduling policies. The rr_interval ++and iso_cpu tunables, and the SCHED_ISO and SCHED_IDLEPRIO policies. In addition ++to this, BFS also uses sub-tick accounting. What BFS does _not_ now feature is ++support for CGROUPS. The average user should neither need to know what these ++are, nor should they need to be using them to have good desktop behaviour. ++ ++rr_interval ++ ++There is only one "scheduler" tunable, the round robin interval. This can be ++accessed in ++ ++ /proc/sys/kernel/rr_interval ++ ++The value is in milliseconds, and the default value is set to 6 on a ++uniprocessor machine, and automatically set to a progressively higher value on ++multiprocessor machines. The reasoning behind increasing the value on more CPUs ++is that the effective latency is decreased by virtue of there being more CPUs on ++BFS (for reasons explained above), and increasing the value allows for less ++cache contention and more throughput. Valid values are from 1 to 1000 ++Decreasing the value will decrease latencies at the cost of decreasing ++throughput, while increasing it will improve throughput, but at the cost of ++worsening latencies. The accuracy of the rr interval is limited by HZ resolution ++of the kernel configuration. Thus, the worst case latencies are usually slightly ++higher than this actual value. The default value of 6 is not an arbitrary one. ++It is based on the fact that humans can detect jitter at approximately 7ms, so ++aiming for much lower latencies is pointless under most circumstances. It is ++worth noting this fact when comparing the latency performance of BFS to other ++schedulers. Worst case latencies being higher than 7ms are far worse than ++average latencies not being in the microsecond range. ++ ++Isochronous scheduling. ++ ++Isochronous scheduling is a unique scheduling policy designed to provide ++near-real-time performance to unprivileged (ie non-root) users without the ++ability to starve the machine indefinitely. Isochronous tasks (which means ++"same time") are set using, for example, the schedtool application like so: ++ ++ schedtool -I -e amarok ++ ++This will start the audio application "amarok" as SCHED_ISO. How SCHED_ISO works ++is that it has a priority level between true realtime tasks and SCHED_NORMAL ++which would allow them to preempt all normal tasks, in a SCHED_RR fashion (ie, ++if multiple SCHED_ISO tasks are running, they purely round robin at rr_interval ++rate). However if ISO tasks run for more than a tunable finite amount of time, ++they are then demoted back to SCHED_NORMAL scheduling. This finite amount of ++time is the percentage of _total CPU_ available across the machine, configurable ++as a percentage in the following "resource handling" tunable (as opposed to a ++scheduler tunable): ++ ++ /proc/sys/kernel/iso_cpu ++ ++and is set to 70% by default. It is calculated over a rolling 5 second average ++Because it is the total CPU available, it means that on a multi CPU machine, it ++is possible to have an ISO task running as realtime scheduling indefinitely on ++just one CPU, as the other CPUs will be available. Setting this to 100 is the ++equivalent of giving all users SCHED_RR access and setting it to 0 removes the ++ability to run any pseudo-realtime tasks. ++ ++A feature of BFS is that it detects when an application tries to obtain a ++realtime policy (SCHED_RR or SCHED_FIFO) and the caller does not have the ++appropriate privileges to use those policies. When it detects this, it will ++give the task SCHED_ISO policy instead. Thus it is transparent to the user. ++Because some applications constantly set their policy as well as their nice ++level, there is potential for them to undo the override specified by the user ++on the command line of setting the policy to SCHED_ISO. To counter this, once ++a task has been set to SCHED_ISO policy, it needs superuser privileges to set ++it back to SCHED_NORMAL. This will ensure the task remains ISO and all child ++processes and threads will also inherit the ISO policy. ++ ++Idleprio scheduling. ++ ++Idleprio scheduling is a scheduling policy designed to give out CPU to a task ++_only_ when the CPU would be otherwise idle. The idea behind this is to allow ++ultra low priority tasks to be run in the background that have virtually no ++effect on the foreground tasks. This is ideally suited to distributed computing ++clients (like setiathome, folding, mprime etc) but can also be used to start ++a video encode or so on without any slowdown of other tasks. To avoid this ++policy from grabbing shared resources and holding them indefinitely, if it ++detects a state where the task is waiting on I/O, the machine is about to ++suspend to ram and so on, it will transiently schedule them as SCHED_NORMAL. As ++per the Isochronous task management, once a task has been scheduled as IDLEPRIO, ++it cannot be put back to SCHED_NORMAL without superuser privileges. Tasks can ++be set to start as SCHED_IDLEPRIO with the schedtool command like so: ++ ++ schedtool -D -e ./mprime ++ ++Subtick accounting. ++ ++It is surprisingly difficult to get accurate CPU accounting, and in many cases, ++the accounting is done by simply determining what is happening at the precise ++moment a timer tick fires off. This becomes increasingly inaccurate as the ++timer tick frequency (HZ) is lowered. It is possible to create an application ++which uses almost 100% CPU, yet by being descheduled at the right time, records ++zero CPU usage. While the main problem with this is that there are possible ++security implications, it is also difficult to determine how much CPU a task ++really does use. BFS tries to use the sub-tick accounting from the TSC clock, ++where possible, to determine real CPU usage. This is not entirely reliable, but ++is far more likely to produce accurate CPU usage data than the existing designs ++and will not show tasks as consuming no CPU usage when they actually are. Thus, ++the amount of CPU reported as being used by BFS will more accurately represent ++how much CPU the task itself is using (as is shown for example by the 'time' ++application), so the reported values may be quite different to other schedulers. ++Values reported as the 'load' are more prone to problems with this design, but ++per process values are closer to real usage. When comparing throughput of BFS ++to other designs, it is important to compare the actual completed work in terms ++of total wall clock time taken and total work done, rather than the reported ++"cpu usage". ++ ++ ++Con Kolivas <kernel@kolivas.org> Fri Aug 27 2010 +diff -Nur a/Documentation/scheduler/sched-MuQSS.txt b/Documentation/scheduler/sched-MuQSS.txt +--- a/Documentation/scheduler/sched-MuQSS.txt 1970-01-01 01:00:00.000000000 +0100 ++++ b/Documentation/scheduler/sched-MuQSS.txt 2019-02-09 17:46:11.991297545 +0000 +@@ -0,0 +1,373 @@ ++MuQSS - The Multiple Queue Skiplist Scheduler by Con Kolivas. ++ ++MuQSS is a per-cpu runqueue variant of the original BFS scheduler with ++one 8 level skiplist per runqueue, and fine grained locking for much more ++scalability. ++ ++ ++Goals. ++ ++The goal of the Multiple Queue Skiplist Scheduler, referred to as MuQSS from ++here on (pronounced mux) is to completely do away with the complex designs of ++the past for the cpu process scheduler and instead implement one that is very ++simple in basic design. The main focus of MuQSS is to achieve excellent desktop ++interactivity and responsiveness without heuristics and tuning knobs that are ++difficult to understand, impossible to model and predict the effect of, and when ++tuned to one workload cause massive detriment to another, while still being ++scalable to many CPUs and processes. ++ ++ ++Design summary. ++ ++MuQSS is best described as per-cpu multiple runqueue, O(log n) insertion, O(1) ++lookup, earliest effective virtual deadline first tickless design, loosely based ++on EEVDF (earliest eligible virtual deadline first) and my previous Staircase ++Deadline scheduler, and evolved from the single runqueue O(n) BFS scheduler. ++Each component shall be described in order to understand the significance of, ++and reasoning for it. ++ ++ ++Design reasoning. ++ ++In BFS, the use of a single runqueue across all CPUs meant that each CPU would ++need to scan the entire runqueue looking for the process with the earliest ++deadline and schedule that next, regardless of which CPU it originally came ++from. This made BFS deterministic with respect to latency and provided ++guaranteed latencies dependent on number of processes and CPUs. The single ++runqueue, however, meant that all CPUs would compete for the single lock ++protecting it, which would lead to increasing lock contention as the number of ++CPUs rose and appeared to limit scalability of common workloads beyond 16 ++logical CPUs. Additionally, the O(n) lookup of the runqueue list obviously ++increased overhead proportionate to the number of queued proecesses and led to ++cache thrashing while iterating over the linked list. ++ ++MuQSS is an evolution of BFS, designed to maintain the same scheduling ++decision mechanism and be virtually deterministic without relying on the ++constrained design of the single runqueue by splitting out the single runqueue ++to be per-CPU and use skiplists instead of linked lists. ++ ++The original reason for going back to a single runqueue design for BFS was that ++once multiple runqueues are introduced, per-CPU or otherwise, there will be ++complex interactions as each runqueue will be responsible for the scheduling ++latency and fairness of the tasks only on its own runqueue, and to achieve ++fairness and low latency across multiple CPUs, any advantage in throughput of ++having CPU local tasks causes other disadvantages. This is due to requiring a ++very complex balancing system to at best achieve some semblance of fairness ++across CPUs and can only maintain relatively low latency for tasks bound to the ++same CPUs, not across them. To increase said fairness and latency across CPUs, ++the advantage of local runqueue locking, which makes for better scalability, is ++lost due to having to grab multiple locks. ++ ++MuQSS works around the problems inherent in multiple runqueue designs by ++making its skip lists priority ordered and through novel use of lockless ++examination of each other runqueue it can decide if it should take the earliest ++deadline task from another runqueue for latency reasons, or for CPU balancing ++reasons. It still does not have a balancing system, choosing to allow the ++next task scheduling decision and task wakeup CPU choice to allow balancing to ++happen by virtue of its choices. ++ ++As a further evolution of the design, MuQSS normally configures sharing of ++runqueues in a logical fashion for when CPU resources are shared for improved ++latency and throughput. By default it shares runqueues and locks between ++multicore siblings. Optionally it can be configured to run with sharing of ++SMT siblings only, all SMP packages or no sharing at all. Additionally it can ++be selected at boot time. ++ ++ ++Design details. ++ ++Custom skip list implementation: ++ ++To avoid the overhead of building up and tearing down skip list structures, ++the variant used by MuQSS has a number of optimisations making it specific for ++its use case in the scheduler. It uses static arrays of 8 'levels' instead of ++building up and tearing down structures dynamically. This makes each runqueue ++only scale O(log N) up to 64k tasks. However as there is one runqueue per CPU ++it means that it scales O(log N) up to 64k x number of logical CPUs which is ++far beyond the realistic task limits each CPU could handle. By being 8 levels ++it also makes the array exactly one cacheline in size. Additionally, each ++skip list node is bidirectional making insertion and removal amortised O(1), ++being O(k) where k is 1-8. Uniquely, we are only ever interested in the very ++first entry in each list at all times with MuQSS, so there is never a need to ++do a search and thus look up is always O(1). In interactive mode, the queues ++will be searched beyond their first entry if the first task is not suitable ++for affinity or SMT nice reasons. ++ ++Task insertion: ++ ++MuQSS inserts tasks into a per CPU runqueue as an O(log N) insertion into ++a custom skip list as described above (based on the original design by William ++Pugh). Insertion is ordered in such a way that there is never a need to do a ++search by ordering tasks according to static priority primarily, and then ++virtual deadline at the time of insertion. ++ ++Niffies: ++ ++Niffies are a monotonic forward moving timer not unlike the "jiffies" but are ++of nanosecond resolution. Niffies are calculated per-runqueue from the high ++resolution TSC timers, and in order to maintain fairness are synchronised ++between CPUs whenever both runqueues are locked concurrently. ++ ++Virtual deadline: ++ ++The key to achieving low latency, scheduling fairness, and "nice level" ++distribution in MuQSS is entirely in the virtual deadline mechanism. The one ++tunable in MuQSS is the rr_interval, or "round robin interval". This is the ++maximum time two SCHED_OTHER (or SCHED_NORMAL, the common scheduling policy) ++tasks of the same nice level will be running for, or looking at it the other ++way around, the longest duration two tasks of the same nice level will be ++delayed for. When a task requests cpu time, it is given a quota (time_slice) ++equal to the rr_interval and a virtual deadline. The virtual deadline is ++offset from the current time in niffies by this equation: ++ ++ niffies + (prio_ratio * rr_interval) ++ ++The prio_ratio is determined as a ratio compared to the baseline of nice -20 ++and increases by 10% per nice level. The deadline is a virtual one only in that ++no guarantee is placed that a task will actually be scheduled by this time, but ++it is used to compare which task should go next. There are three components to ++how a task is next chosen. First is time_slice expiration. If a task runs out ++of its time_slice, it is descheduled, the time_slice is refilled, and the ++deadline reset to that formula above. Second is sleep, where a task no longer ++is requesting CPU for whatever reason. The time_slice and deadline are _not_ ++adjusted in this case and are just carried over for when the task is next ++scheduled. Third is preemption, and that is when a newly waking task is deemed ++higher priority than a currently running task on any cpu by virtue of the fact ++that it has an earlier virtual deadline than the currently running task. The ++earlier deadline is the key to which task is next chosen for the first and ++second cases. ++ ++The CPU proportion of different nice tasks works out to be approximately the ++ ++ (prio_ratio difference)^2 ++ ++The reason it is squared is that a task's deadline does not change while it is ++running unless it runs out of time_slice. Thus, even if the time actually ++passes the deadline of another task that is queued, it will not get CPU time ++unless the current running task deschedules, and the time "base" (niffies) is ++constantly moving. ++ ++Task lookup: ++ ++As tasks are already pre-ordered according to anticipated scheduling order in ++the skip lists, lookup for the next suitable task per-runqueue is always a ++matter of simply selecting the first task in the 0th level skip list entry. ++In order to maintain optimal latency and fairness across CPUs, MuQSS does a ++novel examination of every other runqueue in cache locality order, choosing the ++best task across all runqueues. This provides near-determinism of how long any ++task across the entire system may wait before receiving CPU time. The other ++runqueues are first examine lockless and then trylocked to minimise the ++potential lock contention if they are likely to have a suitable better task. ++Each other runqueue lock is only held for as long as it takes to examine the ++entry for suitability. In "interactive" mode, the default setting, MuQSS will ++look for the best deadline task across all CPUs, while in !interactive mode, ++it will only select a better deadline task from another CPU if it is more ++heavily laden than the current one. ++ ++Lookup is therefore O(k) where k is number of CPUs. ++ ++ ++Latency. ++ ++Through the use of virtual deadlines to govern the scheduling order of normal ++tasks, queue-to-activation latency per runqueue is guaranteed to be bound by ++the rr_interval tunable which is set to 6ms by default. This means that the ++longest a CPU bound task will wait for more CPU is proportional to the number ++of running tasks and in the common case of 0-2 running tasks per CPU, will be ++under the 7ms threshold for human perception of jitter. Additionally, as newly ++woken tasks will have an early deadline from their previous runtime, the very ++tasks that are usually latency sensitive will have the shortest interval for ++activation, usually preempting any existing CPU bound tasks. ++ ++Tickless expiry: ++ ++A feature of MuQSS is that it is not tied to the resolution of the chosen tick ++rate in Hz, instead depending entirely on the high resolution timers where ++possible for sub-millisecond accuracy on timeouts regarless of the underlying ++tick rate. This allows MuQSS to be run with the low overhead of low Hz rates ++such as 100 by default, benefiting from the improved throughput and lower ++power usage it provides. Another advantage of this approach is that in ++combination with the Full No HZ option, which disables ticks on running task ++CPUs instead of just idle CPUs, the tick can be disabled at all times ++regardless of how many tasks are running instead of being limited to just one ++running task. Note that this option is NOT recommended for regular desktop ++users. ++ ++ ++Scalability and balancing. ++ ++Unlike traditional approaches where balancing is a combination of CPU selection ++at task wakeup and intermittent balancing based on a vast array of rules set ++according to architecture, busyness calculations and special case management, ++MuQSS indirectly balances on the fly at task wakeup and next task selection. ++During initialisation, MuQSS creates a cache coherency ordered list of CPUs for ++each logical CPU and uses this to aid task/CPU selection when CPUs are busy. ++Additionally it selects any idle CPUs, if they are available, at any time over ++busy CPUs according to the following preference: ++ ++ * Same thread, idle or busy cache, idle or busy threads ++ * Other core, same cache, idle or busy cache, idle threads. ++ * Same node, other CPU, idle cache, idle threads. ++ * Same node, other CPU, busy cache, idle threads. ++ * Other core, same cache, busy threads. ++ * Same node, other CPU, busy threads. ++ * Other node, other CPU, idle cache, idle threads. ++ * Other node, other CPU, busy cache, idle threads. ++ * Other node, other CPU, busy threads. ++ ++Mux is therefore SMT, MC and Numa aware without the need for extra ++intermittent balancing to maintain CPUs busy and make the most of cache ++coherency. ++ ++ ++Features ++ ++As the initial prime target audience for MuQSS was the average desktop user, it ++was designed to not need tweaking, tuning or have features set to obtain benefit ++from it. Thus the number of knobs and features has been kept to an absolute ++minimum and should not require extra user input for the vast majority of cases. ++There are 3 optional tunables, and 2 extra scheduling policies. The rr_interval, ++interactive, and iso_cpu tunables, and the SCHED_ISO and SCHED_IDLEPRIO ++policies. In addition to this, MuQSS also uses sub-tick accounting. What MuQSS ++does _not_ now feature is support for CGROUPS. The average user should neither ++need to know what these are, nor should they need to be using them to have good ++desktop behaviour. However since some applications refuse to work without ++cgroups, one can enable them with MuQSS as a stub and the filesystem will be ++created which will allow the applications to work. ++ ++rr_interval: ++ ++ /proc/sys/kernel/rr_interval ++ ++The value is in milliseconds, and the default value is set to 6. Valid values ++are from 1 to 1000 Decreasing the value will decrease latencies at the cost of ++decreasing throughput, while increasing it will improve throughput, but at the ++cost of worsening latencies. It is based on the fact that humans can detect ++jitter at approximately 7ms, so aiming for much lower latencies is pointless ++under most circumstances. It is worth noting this fact when comparing the ++latency performance of MuQSS to other schedulers. Worst case latencies being ++higher than 7ms are far worse than average latencies not being in the ++microsecond range. ++ ++interactive: ++ ++ /proc/sys/kernel/interactive ++ ++The value is a simple boolean of 1 for on and 0 for off and is set to on by ++default. Disabling this will disable the near-determinism of MuQSS when ++selecting the next task by not examining all CPUs for the earliest deadline ++task, or which CPU to wake to, instead prioritising CPU balancing for improved ++throughput. Latency will still be bound by rr_interval, but on a per-CPU basis ++instead of across the whole system. ++ ++Runqueue sharing. ++ ++By default MuQSS chooses to share runqueue resources (specifically the skip ++list and locking) between multicore siblings. It is configurable at build time ++to select between None, SMT, MC and SMP, corresponding to no sharing, sharing ++only between simultaneous mulithreading siblings, multicore siblings, or ++symmetric multiprocessing physical packages. Additionally it can be se at ++bootime with the use of the rqshare parameter. The reason for configurability ++is that some architectures have CPUs with many multicore siblings (>= 16) ++where it may be detrimental to throughput to share runqueues and another ++sharing option may be desirable. Additionally, more sharing than usual can ++improve latency on a system-wide level at the expense of throughput if desired. ++ ++The options are: ++none, smt, mc, smp ++ ++eg: ++ rqshare=mc ++ ++Isochronous scheduling: ++ ++Isochronous scheduling is a unique scheduling policy designed to provide ++near-real-time performance to unprivileged (ie non-root) users without the ++ability to starve the machine indefinitely. Isochronous tasks (which means ++"same time") are set using, for example, the schedtool application like so: ++ ++ schedtool -I -e amarok ++ ++This will start the audio application "amarok" as SCHED_ISO. How SCHED_ISO works ++is that it has a priority level between true realtime tasks and SCHED_NORMAL ++which would allow them to preempt all normal tasks, in a SCHED_RR fashion (ie, ++if multiple SCHED_ISO tasks are running, they purely round robin at rr_interval ++rate). However if ISO tasks run for more than a tunable finite amount of time, ++they are then demoted back to SCHED_NORMAL scheduling. This finite amount of ++time is the percentage of CPU available per CPU, configurable as a percentage in ++the following "resource handling" tunable (as opposed to a scheduler tunable): ++ ++iso_cpu: ++ ++ /proc/sys/kernel/iso_cpu ++ ++and is set to 70% by default. It is calculated over a rolling 5 second average ++Because it is the total CPU available, it means that on a multi CPU machine, it ++is possible to have an ISO task running as realtime scheduling indefinitely on ++just one CPU, as the other CPUs will be available. Setting this to 100 is the ++equivalent of giving all users SCHED_RR access and setting it to 0 removes the ++ability to run any pseudo-realtime tasks. ++ ++A feature of MuQSS is that it detects when an application tries to obtain a ++realtime policy (SCHED_RR or SCHED_FIFO) and the caller does not have the ++appropriate privileges to use those policies. When it detects this, it will ++give the task SCHED_ISO policy instead. Thus it is transparent to the user. ++ ++ ++Idleprio scheduling: ++ ++Idleprio scheduling is a scheduling policy designed to give out CPU to a task ++_only_ when the CPU would be otherwise idle. The idea behind this is to allow ++ultra low priority tasks to be run in the background that have virtually no ++effect on the foreground tasks. This is ideally suited to distributed computing ++clients (like setiathome, folding, mprime etc) but can also be used to start a ++video encode or so on without any slowdown of other tasks. To avoid this policy ++from grabbing shared resources and holding them indefinitely, if it detects a ++state where the task is waiting on I/O, the machine is about to suspend to ram ++and so on, it will transiently schedule them as SCHED_NORMAL. Once a task has ++been scheduled as IDLEPRIO, it cannot be put back to SCHED_NORMAL without ++superuser privileges since it is effectively a lower scheduling policy. Tasks ++can be set to start as SCHED_IDLEPRIO with the schedtool command like so: ++ ++schedtool -D -e ./mprime ++ ++Subtick accounting: ++ ++It is surprisingly difficult to get accurate CPU accounting, and in many cases, ++the accounting is done by simply determining what is happening at the precise ++moment a timer tick fires off. This becomes increasingly inaccurate as the timer ++tick frequency (HZ) is lowered. It is possible to create an application which ++uses almost 100% CPU, yet by being descheduled at the right time, records zero ++CPU usage. While the main problem with this is that there are possible security ++implications, it is also difficult to determine how much CPU a task really does ++use. Mux uses sub-tick accounting from the TSC clock to determine real CPU ++usage. Thus, the amount of CPU reported as being used by MuQSS will more ++accurately represent how much CPU the task itself is using (as is shown for ++example by the 'time' application), so the reported values may be quite ++different to other schedulers. When comparing throughput of MuQSS to other ++designs, it is important to compare the actual completed work in terms of total ++wall clock time taken and total work done, rather than the reported "cpu usage". ++ ++Symmetric MultiThreading (SMT) aware nice: ++ ++SMT, a.k.a. hyperthreading, is a very common feature on modern CPUs. While the ++logical CPU count rises by adding thread units to each CPU core, allowing more ++than one task to be run simultaneously on the same core, the disadvantage of it ++is that the CPU power is shared between the tasks, not summating to the power ++of two CPUs. The practical upshot of this is that two tasks running on ++separate threads of the same core run significantly slower than if they had one ++core each to run on. While smart CPU selection allows each task to have a core ++to itself whenever available (as is done on MuQSS), it cannot offset the ++slowdown that occurs when the cores are all loaded and only a thread is left. ++Most of the time this is harmless as the CPU is effectively overloaded at this ++point and the extra thread is of benefit. However when running a niced task in ++the presence of an un-niced task (say nice 19 v nice 0), the nice task gets ++precisely the same amount of CPU power as the unniced one. MuQSS has an ++optional configuration feature known as SMT-NICE which selectively idles the ++secondary niced thread for a period proportional to the nice difference, ++allowing CPU distribution according to nice level to be maintained, at the ++expense of a small amount of extra overhead. If this is configured in on a ++machine without SMT threads, the overhead is minimal. ++ ++ ++Con Kolivas <kernel@kolivas.org> Sat, 29th October 2016 +diff -Nur a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt +--- a/Documentation/sysctl/kernel.txt 2019-02-09 17:20:30.451820228 +0000 ++++ b/Documentation/sysctl/kernel.txt 2019-02-09 17:46:11.991297545 +0000 +@@ -41,6 +41,7 @@ + - hung_task_check_interval_secs + - hung_task_warnings + - hyperv_record_panic_msg ++- iso_cpu + - kexec_load_disabled + - kptr_restrict + - l2cr [ PPC only ] +@@ -76,6 +77,7 @@ + - randomize_va_space + - real-root-dev ==> Documentation/admin-guide/initrd.rst + - reboot-cmd [ SPARC only ] ++- rr_interval + - rtsig-max + - rtsig-nr + - seccomp/ ==> Documentation/userspace-api/seccomp_filter.rst +@@ -98,6 +100,7 @@ + - unknown_nmi_panic + - watchdog + - watchdog_thresh ++- yield_type + - version + + ============================================================== +@@ -436,6 +439,16 @@ + + ============================================================== + ++iso_cpu: (MuQSS CPU scheduler only). ++ ++This sets the percentage cpu that the unprivileged SCHED_ISO tasks can ++run effectively at realtime priority, averaged over a rolling five ++seconds over the -whole- system, meaning all cpus. ++ ++Set to 70 (percent) by default. ++ ++============================================================== ++ + l2cr: (PPC only) + + This flag controls the L2 cache of G3 processor boards. If +@@ -863,6 +876,20 @@ + + ============================================================== + ++rr_interval: (MuQSS CPU scheduler only) ++ ++This is the smallest duration that any cpu process scheduling unit ++will run for. Increasing this value can increase throughput of cpu ++bound tasks substantially but at the expense of increased latencies ++overall. Conversely decreasing it will decrease average and maximum ++latencies but at the expense of throughput. This value is in ++milliseconds and the default value chosen depends on the number of ++cpus available at scheduler initialisation with a minimum of 6. ++ ++Valid values are from 1-1000. ++ ++============================================================== ++ + rtsig-max & rtsig-nr: + + The file rtsig-max can be used to tune the maximum number +@@ -1123,3 +1150,13 @@ + tunable to zero will disable lockup detection altogether. + + ============================================================== ++ ++yield_type: (MuQSS CPU scheduler only) ++ ++This determines what type of yield calls to sched_yield will perform. ++ ++ 0: No yield. ++ 1: Yield only to better priority/deadline tasks. (default) ++ 2: Expire timeslice and recalculate deadline. ++ ++============================================================== +diff -Nur a/fs/proc/base.c b/fs/proc/base.c +--- a/fs/proc/base.c 2019-02-06 16:30:16.000000000 +0000 ++++ b/fs/proc/base.c 2019-02-09 17:46:11.991297545 +0000 +@@ -459,7 +459,7 @@ + seq_printf(m, "0 0 0\n"); + else + seq_printf(m, "%llu %llu %lu\n", +- (unsigned long long)task->se.sum_exec_runtime, ++ (unsigned long long)tsk_seruntime(task), + (unsigned long long)task->sched_info.run_delay, + task->sched_info.pcount); + +diff -Nur a/include/linux/init_task.h b/include/linux/init_task.h +--- a/include/linux/init_task.h 2019-02-06 16:30:16.000000000 +0000 ++++ b/include/linux/init_task.h 2019-02-09 17:46:11.991297545 +0000 +@@ -46,7 +46,11 @@ + #define INIT_CPU_TIMERS(s) + #endif + ++#ifdef CONFIG_SCHED_MUQSS ++#define INIT_TASK_COMM "MuQSS" ++#else + #define INIT_TASK_COMM "swapper" ++#endif + + /* Attach to the init_task data structure for proper alignment */ + #ifdef CONFIG_ARCH_TASK_STRUCT_ON_STACK +diff -Nur a/include/linux/ioprio.h b/include/linux/ioprio.h +--- a/include/linux/ioprio.h 2019-02-06 16:30:16.000000000 +0000 ++++ b/include/linux/ioprio.h 2019-02-09 17:46:11.991297545 +0000 +@@ -53,6 +53,8 @@ + */ + static inline int task_nice_ioprio(struct task_struct *task) + { ++ if (iso_task(task)) ++ return 0; + return (task_nice(task) + 20) / 5; + } + +diff -Nur a/include/linux/sched/nohz.h b/include/linux/sched/nohz.h +--- a/include/linux/sched/nohz.h 2019-02-06 16:30:16.000000000 +0000 ++++ b/include/linux/sched/nohz.h 2019-02-09 17:46:11.991297545 +0000 +@@ -6,7 +6,7 @@ + * This is the interface between the scheduler and nohz/dynticks: + */ + +-#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON) ++#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON) && !defined(CONFIG_SCHED_MUQSS) + extern void cpu_load_update_nohz_start(void); + extern void cpu_load_update_nohz_stop(void); + #else +@@ -21,7 +21,7 @@ + static inline void nohz_balance_enter_idle(int cpu) { } + #endif + +-#ifdef CONFIG_NO_HZ_COMMON ++#if defined(CONFIG_NO_HZ_COMMON) && !defined(CONFIG_SCHED_MUQSS) + void calc_load_nohz_start(void); + void calc_load_nohz_stop(void); + #else +diff -Nur a/include/linux/sched/prio.h b/include/linux/sched/prio.h +--- a/include/linux/sched/prio.h 2019-02-06 16:30:16.000000000 +0000 ++++ b/include/linux/sched/prio.h 2019-02-09 17:46:11.991297545 +0000 +@@ -20,8 +20,20 @@ + */ + + #define MAX_USER_RT_PRIO 100 ++ ++#ifdef CONFIG_SCHED_MUQSS ++/* Note different MAX_RT_PRIO */ ++#define MAX_RT_PRIO (MAX_USER_RT_PRIO + 1) ++ ++#define ISO_PRIO (MAX_RT_PRIO) ++#define NORMAL_PRIO (MAX_RT_PRIO + 1) ++#define IDLE_PRIO (MAX_RT_PRIO + 2) ++#define PRIO_LIMIT ((IDLE_PRIO) + 1) ++#else /* CONFIG_SCHED_MUQSS */ + #define MAX_RT_PRIO MAX_USER_RT_PRIO + ++#endif /* CONFIG_SCHED_MUQSS */ ++ + #define MAX_PRIO (MAX_RT_PRIO + NICE_WIDTH) + #define DEFAULT_PRIO (MAX_RT_PRIO + NICE_WIDTH / 2) + +diff -Nur a/include/linux/sched/rt.h b/include/linux/sched/rt.h +--- a/include/linux/sched/rt.h 2019-02-06 16:30:16.000000000 +0000 ++++ b/include/linux/sched/rt.h 2019-02-09 17:46:11.991297545 +0000 +@@ -24,8 +24,10 @@ + + if (policy == SCHED_FIFO || policy == SCHED_RR) + return true; ++#ifndef CONFIG_SCHED_MUQSS + if (policy == SCHED_DEADLINE) + return true; ++#endif + return false; + } + +diff -Nur a/include/linux/sched/task.h b/include/linux/sched/task.h +--- a/include/linux/sched/task.h 2019-02-06 16:30:16.000000000 +0000 ++++ b/include/linux/sched/task.h 2019-02-09 17:46:11.991297545 +0000 +@@ -80,7 +80,7 @@ + extern void free_task(struct task_struct *tsk); + + /* sched_exec is called by processes performing an exec */ +-#ifdef CONFIG_SMP ++#if defined(CONFIG_SMP) && !defined(CONFIG_SCHED_MUQSS) + extern void sched_exec(void); + #else + #define sched_exec() {} +diff -Nur a/include/linux/sched.h b/include/linux/sched.h +--- a/include/linux/sched.h 2019-02-06 16:30:16.000000000 +0000 ++++ b/include/linux/sched.h 2019-02-09 17:46:11.991297545 +0000 +@@ -28,6 +28,9 @@ + #include <linux/mm_types_task.h> + #include <linux/task_io_accounting.h> + #include <linux/rseq.h> ++#ifdef CONFIG_SCHED_MUQSS ++#include <linux/skip_list.h> ++#endif + + /* task_struct member predeclarations (sorted alphabetically): */ + struct audit_context; +@@ -613,9 +616,11 @@ + unsigned int flags; + unsigned int ptrace; + ++#if defined(CONFIG_SMP) || defined(CONFIG_SCHED_MUQSS) ++ int on_cpu; ++#endif + #ifdef CONFIG_SMP + struct llist_node wake_entry; +- int on_cpu; + #ifdef CONFIG_THREAD_INFO_IN_TASK + /* Current CPU: */ + unsigned int cpu; +@@ -640,10 +645,25 @@ + int static_prio; + int normal_prio; + unsigned int rt_priority; ++#ifdef CONFIG_SCHED_MUQSS ++ int time_slice; ++ u64 deadline; ++ skiplist_node node; /* Skip list node */ ++ u64 last_ran; ++ u64 sched_time; /* sched_clock time spent running */ ++#ifdef CONFIG_SMT_NICE ++ int smt_bias; /* Policy/nice level bias across smt siblings */ ++#endif ++#ifdef CONFIG_HOTPLUG_CPU ++ bool zerobound; /* Bound to CPU0 for hotplug */ ++#endif ++ unsigned long rt_timeout; ++#else /* CONFIG_SCHED_MUQSS */ + + const struct sched_class *sched_class; + struct sched_entity se; + struct sched_rt_entity rt; ++#endif + #ifdef CONFIG_CGROUP_SCHED + struct task_group *sched_task_group; + #endif +@@ -798,6 +818,10 @@ + u64 utimescaled; + u64 stimescaled; + #endif ++#ifdef CONFIG_SCHED_MUQSS ++ /* Unbanked cpu time */ ++ unsigned long utime_ns, stime_ns; ++#endif + u64 gtime; + struct prev_cputime prev_cputime; + #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN +@@ -1210,6 +1234,40 @@ + */ + }; + ++#ifdef CONFIG_SCHED_MUQSS ++#define tsk_seruntime(t) ((t)->sched_time) ++#define tsk_rttimeout(t) ((t)->rt_timeout) ++ ++static inline void tsk_cpus_current(struct task_struct *p) ++{ ++} ++ ++void print_scheduler_version(void); ++ ++static inline bool iso_task(struct task_struct *p) ++{ ++ return (p->policy == SCHED_ISO); ++} ++#else /* CFS */ ++#define tsk_seruntime(t) ((t)->se.sum_exec_runtime) ++#define tsk_rttimeout(t) ((t)->rt.timeout) ++ ++static inline void tsk_cpus_current(struct task_struct *p) ++{ ++ p->nr_cpus_allowed = current->nr_cpus_allowed; ++} ++ ++static inline void print_scheduler_version(void) ++{ ++ printk(KERN_INFO "CFS CPU scheduler.\n"); ++} ++ ++static inline bool iso_task(struct task_struct *p) ++{ ++ return false; ++} ++#endif /* CONFIG_SCHED_MUQSS */ ++ + static inline struct pid *task_pid(struct task_struct *task) + { + return task->thread_pid; +diff -Nur a/include/linux/skip_list.h b/include/linux/skip_list.h +--- a/include/linux/skip_list.h 1970-01-01 01:00:00.000000000 +0100 ++++ b/include/linux/skip_list.h 2019-02-09 17:46:11.991297545 +0000 +@@ -0,0 +1,33 @@ ++#ifndef _LINUX_SKIP_LISTS_H ++#define _LINUX_SKIP_LISTS_H ++typedef u64 keyType; ++typedef void *valueType; ++ ++typedef struct nodeStructure skiplist_node; ++ ++struct nodeStructure { ++ int level; /* Levels in this structure */ ++ keyType key; ++ valueType value; ++ skiplist_node *next[8]; ++ skiplist_node *prev[8]; ++}; ++ ++typedef struct listStructure { ++ int entries; ++ int level; /* Maximum level of the list ++ (1 more than the number of levels in the list) */ ++ skiplist_node *header; /* pointer to header */ ++} skiplist; ++ ++void skiplist_init(skiplist_node *slnode); ++skiplist *new_skiplist(skiplist_node *slnode); ++void free_skiplist(skiplist *l); ++void skiplist_node_init(skiplist_node *node); ++void skiplist_insert(skiplist *l, skiplist_node *node, keyType key, valueType value, unsigned int randseed); ++void skiplist_delete(skiplist *l, skiplist_node *node); ++ ++static inline bool skiplist_node_empty(skiplist_node *node) { ++ return (!node->next[0]); ++} ++#endif /* _LINUX_SKIP_LISTS_H */ +diff -Nur a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h +--- a/include/uapi/linux/sched.h 2019-02-06 16:30:16.000000000 +0000 ++++ b/include/uapi/linux/sched.h 2019-02-09 17:46:11.991297545 +0000 +@@ -37,9 +37,16 @@ + #define SCHED_FIFO 1 + #define SCHED_RR 2 + #define SCHED_BATCH 3 +-/* SCHED_ISO: reserved but not implemented yet */ ++/* SCHED_ISO: Implemented on MuQSS only */ + #define SCHED_IDLE 5 ++#ifdef CONFIG_SCHED_MUQSS ++#define SCHED_ISO 4 ++#define SCHED_IDLEPRIO SCHED_IDLE ++#define SCHED_MAX (SCHED_IDLEPRIO) ++#define SCHED_RANGE(policy) ((policy) <= SCHED_MAX) ++#else /* CONFIG_SCHED_MUQSS */ + #define SCHED_DEADLINE 6 ++#endif /* CONFIG_SCHED_MUQSS */ + + /* Can be ORed in to make sure the process is reverted back to SCHED_NORMAL on fork */ + #define SCHED_RESET_ON_FORK 0x40000000 +diff -Nur a/init/init_task.c b/init/init_task.c +--- a/init/init_task.c 2019-02-06 16:30:16.000000000 +0000 ++++ b/init/init_task.c 2019-02-09 17:46:11.991297545 +0000 +@@ -67,9 +67,17 @@ + .stack = init_stack, + .usage = ATOMIC_INIT(2), + .flags = PF_KTHREAD, ++#ifdef CONFIG_SCHED_MUQSS ++ .prio = NORMAL_PRIO, ++ .static_prio = MAX_PRIO-20, ++ .normal_prio = NORMAL_PRIO, ++ .deadline = 0, ++ .time_slice = 1000000, ++#else + .prio = MAX_PRIO - 20, + .static_prio = MAX_PRIO - 20, + .normal_prio = MAX_PRIO - 20, ++#endif + .policy = SCHED_NORMAL, + .cpus_allowed = CPU_MASK_ALL, + .nr_cpus_allowed= NR_CPUS, +@@ -78,6 +86,7 @@ + .restart_block = { + .fn = do_no_restart_syscall, + }, ++#ifndef CONFIG_SCHED_MUQSS + .se = { + .group_node = LIST_HEAD_INIT(init_task.se.group_node), + }, +@@ -85,6 +94,7 @@ + .run_list = LIST_HEAD_INIT(init_task.rt.run_list), + .time_slice = RR_TIMESLICE, + }, ++#endif + .tasks = LIST_HEAD_INIT(init_task.tasks), + #ifdef CONFIG_SMP + .pushable_tasks = PLIST_NODE_INIT(init_task.pushable_tasks, MAX_PRIO), +diff -Nur a/init/Kconfig b/init/Kconfig +--- a/init/Kconfig 2019-02-09 17:20:30.481821193 +0000 ++++ b/init/Kconfig 2019-02-09 17:46:11.991297545 +0000 +@@ -45,6 +45,18 @@ + + menu "General setup" + ++config SCHED_MUQSS ++ bool "MuQSS cpu scheduler" ++ select HIGH_RES_TIMERS ++ ---help--- ++ The Multiple Queue Skiplist Scheduler for excellent interactivity and ++ responsiveness on the desktop and highly scalable deterministic ++ low latency on any hardware. ++ ++ Say Y here. ++ default y ++ ++ + config BROKEN + bool + +@@ -653,6 +665,7 @@ + depends on ARCH_SUPPORTS_NUMA_BALANCING + depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY + depends on SMP && NUMA && MIGRATION ++ depends on !SCHED_MUQSS + help + This option adds support for automatic NUMA aware memory/task placement. + The mechanism is quite primitive and is based on migrating memory when +@@ -760,9 +773,13 @@ + help + This feature lets CPU scheduler recognize task groups and control CPU + bandwidth allocation to such task groups. It uses cgroups to group +- tasks. ++ tasks. In combination with MuQSS this is purely a STUB to create the ++ files associated with the CPU controller cgroup but most of the ++ controls do nothing. This is useful for working in environments and ++ with applications that will only work if this control group is ++ present. + +-if CGROUP_SCHED ++if CGROUP_SCHED && !SCHED_MUQSS + config FAIR_GROUP_SCHED + bool "Group scheduling for SCHED_OTHER" + depends on CGROUP_SCHED +@@ -869,6 +886,7 @@ + + config CGROUP_CPUACCT + bool "Simple CPU accounting controller" ++ depends on !SCHED_MUQSS + help + Provides a simple controller for monitoring the + total CPU consumed by the tasks in a cgroup. +@@ -987,6 +1005,7 @@ + + config SCHED_AUTOGROUP + bool "Automatic process group scheduling" ++ depends on !SCHED_MUQSS + select CGROUPS + select CGROUP_SCHED + select FAIR_GROUP_SCHED +diff -Nur a/init/main.c b/init/main.c +--- a/init/main.c 2019-02-06 16:30:16.000000000 +0000 ++++ b/init/main.c 2019-02-09 17:46:11.991297545 +0000 +@@ -1079,6 +1079,8 @@ + + rcu_end_inkernel_boot(); + ++ print_scheduler_version(); ++ + if (ramdisk_execute_command) { + ret = run_init_process(ramdisk_execute_command); + if (!ret) +diff -Nur a/kernel/delayacct.c b/kernel/delayacct.c +--- a/kernel/delayacct.c 2019-02-06 16:30:16.000000000 +0000 ++++ b/kernel/delayacct.c 2019-02-09 17:46:11.991297545 +0000 +@@ -115,7 +115,7 @@ + */ + t1 = tsk->sched_info.pcount; + t2 = tsk->sched_info.run_delay; +- t3 = tsk->se.sum_exec_runtime; ++ t3 = tsk_seruntime(tsk); + + d->cpu_count += t1; + +diff -Nur a/kernel/exit.c b/kernel/exit.c +--- a/kernel/exit.c 2019-02-06 16:30:16.000000000 +0000 ++++ b/kernel/exit.c 2019-02-09 17:46:11.991297545 +0000 +@@ -130,7 +130,7 @@ + sig->curr_target = next_thread(tsk); + } + +- add_device_randomness((const void*) &tsk->se.sum_exec_runtime, ++ add_device_randomness((const void*) &tsk_seruntime(tsk), + sizeof(unsigned long long)); + + /* +@@ -151,7 +151,7 @@ + sig->inblock += task_io_get_inblock(tsk); + sig->oublock += task_io_get_oublock(tsk); + task_io_accounting_add(&sig->ioac, &tsk->ioac); +- sig->sum_sched_runtime += tsk->se.sum_exec_runtime; ++ sig->sum_sched_runtime += tsk_seruntime(tsk); + sig->nr_threads--; + __unhash_process(tsk, group_dead); + write_sequnlock(&sig->stats_lock); +diff -Nur a/kernel/kthread.c b/kernel/kthread.c +--- a/kernel/kthread.c 2019-02-06 16:30:16.000000000 +0000 ++++ b/kernel/kthread.c 2019-02-09 17:46:11.991297545 +0000 +@@ -424,6 +424,34 @@ + } + EXPORT_SYMBOL(kthread_bind); + ++#if defined(CONFIG_SCHED_MUQSS) && defined(CONFIG_SMP) ++extern void __do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask); ++ ++/* ++ * new_kthread_bind is a special variant of __kthread_bind_mask. ++ * For new threads to work on muqss we want to call do_set_cpus_allowed ++ * without the task_cpu being set and the task rescheduled until they're ++ * rescheduled on their own so we call __do_set_cpus_allowed directly which ++ * only changes the cpumask. This is particularly important for smpboot threads ++ * to work. ++ */ ++static void new_kthread_bind(struct task_struct *p, unsigned int cpu) ++{ ++ unsigned long flags; ++ ++ if (WARN_ON(!wait_task_inactive(p, TASK_UNINTERRUPTIBLE))) ++ return; ++ ++ /* It's safe because the task is inactive. */ ++ raw_spin_lock_irqsave(&p->pi_lock, flags); ++ __do_set_cpus_allowed(p, cpumask_of(cpu)); ++ p->flags |= PF_NO_SETAFFINITY; ++ raw_spin_unlock_irqrestore(&p->pi_lock, flags); ++} ++#else ++#define new_kthread_bind(p, cpu) kthread_bind(p, cpu) ++#endif ++ + /** + * kthread_create_on_cpu - Create a cpu bound kthread + * @threadfn: the function to run until signal_pending(current). +@@ -445,7 +473,7 @@ + cpu); + if (IS_ERR(p)) + return p; +- kthread_bind(p, cpu); ++ new_kthread_bind(p, cpu); + /* CPU hotplug need to bind once again when unparking the thread. */ + set_bit(KTHREAD_IS_PER_CPU, &to_kthread(p)->flags); + to_kthread(p)->cpu = cpu; +diff -Nur a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c +--- a/kernel/livepatch/transition.c 2019-02-06 16:30:16.000000000 +0000 ++++ b/kernel/livepatch/transition.c 2019-02-09 17:46:11.991297545 +0000 +@@ -290,6 +290,12 @@ + return 0; + } + ++#ifdef CONFIG_SCHED_MUQSS ++typedef unsigned long rq_flags_t; ++#else ++typedef struct rq_flags rq_flag_t; ++#endif ++ + /* + * Try to safely switch a task to the target patch state. If it's currently + * running, or it's sleeping on a to-be-patched or to-be-unpatched function, or +@@ -298,7 +304,7 @@ + static bool klp_try_switch_task(struct task_struct *task) + { + struct rq *rq; +- struct rq_flags flags; ++ rq_flags_t flags; + int ret; + bool success = false; + char err_buf[STACK_ERR_BUF_SIZE]; +diff -Nur a/kernel/Makefile b/kernel/Makefile +--- a/kernel/Makefile 2019-02-06 16:30:16.000000000 +0000 ++++ b/kernel/Makefile 2019-02-09 17:46:11.991297545 +0000 +@@ -10,7 +10,7 @@ + extable.o params.o \ + kthread.o sys_ni.o nsproxy.o \ + notifier.o ksysfs.o cred.o reboot.o \ +- async.o range.o smpboot.o ucount.o ++ async.o range.o smpboot.o ucount.o skip_list.o + + obj-$(CONFIG_MODULES) += kmod.o + obj-$(CONFIG_MULTIUSER) += groups.o +diff -Nur a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig +--- a/kernel/rcu/Kconfig 2019-02-06 16:30:16.000000000 +0000 ++++ b/kernel/rcu/Kconfig 2019-02-09 17:46:11.991297545 +0000 +@@ -93,7 +93,7 @@ + config CONTEXT_TRACKING_FORCE + bool "Force context tracking" + depends on CONTEXT_TRACKING +- default y if !NO_HZ_FULL ++ default y if !NO_HZ_FULL && !SCHED_MUQSS + help + The major pre-requirement for full dynticks to work is to + support the context tracking subsystem. But there are also +diff -Nur a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c +--- a/kernel/sched/cpufreq_schedutil.c 2019-02-06 16:30:16.000000000 +0000 ++++ b/kernel/sched/cpufreq_schedutil.c 2019-02-09 17:46:12.001297867 +0000 +@@ -177,6 +177,12 @@ + return cpufreq_driver_resolve_freq(policy, freq); + } + ++#ifdef CONFIG_SCHED_MUQSS ++#define rt_rq_runnable(rq_rt) rt_rq_is_runnable(rq) ++#else ++#define rt_rq_runnable(rq_rt) rt_rq_is_runnable(&rq->rt) ++#endif ++ + /* + * This function computes an effective utilization for the given CPU, to be + * used for frequency selection given the linear relation: f = u * f_max. +@@ -205,7 +211,7 @@ + sg_cpu->max = max = arch_scale_cpu_capacity(NULL, sg_cpu->cpu); + sg_cpu->bw_dl = cpu_bw_dl(rq); + +- if (rt_rq_is_runnable(&rq->rt)) ++ if (rt_rq_runnable(rq)) + return max; + + /* +@@ -626,7 +632,11 @@ + struct task_struct *thread; + struct sched_attr attr = { + .size = sizeof(struct sched_attr), ++#ifdef CONFIG_SCHED_MUQSS ++ .sched_policy = SCHED_RR, ++#else + .sched_policy = SCHED_DEADLINE, ++#endif + .sched_flags = SCHED_FLAG_SUGOV, + .sched_nice = 0, + .sched_priority = 0, +diff -Nur a/kernel/sched/cpupri.h b/kernel/sched/cpupri.h +--- a/kernel/sched/cpupri.h 2019-02-06 16:30:16.000000000 +0000 ++++ b/kernel/sched/cpupri.h 2019-02-09 17:46:12.001297867 +0000 +@@ -17,9 +17,11 @@ + int *cpu_to_pri; + }; + ++#ifndef CONFIG_SCHED_MUQSS + #ifdef CONFIG_SMP + int cpupri_find(struct cpupri *cp, struct task_struct *p, struct cpumask *lowest_mask); + void cpupri_set(struct cpupri *cp, int cpu, int pri); + int cpupri_init(struct cpupri *cp); + void cpupri_cleanup(struct cpupri *cp); + #endif ++#endif +diff -Nur a/kernel/sched/cputime.c b/kernel/sched/cputime.c +--- a/kernel/sched/cputime.c 2019-02-06 16:30:16.000000000 +0000 ++++ b/kernel/sched/cputime.c 2019-02-09 17:46:12.001297867 +0000 +@@ -265,26 +265,6 @@ + return accounted; + } + +-#ifdef CONFIG_64BIT +-static inline u64 read_sum_exec_runtime(struct task_struct *t) +-{ +- return t->se.sum_exec_runtime; +-} +-#else +-static u64 read_sum_exec_runtime(struct task_struct *t) +-{ +- u64 ns; +- struct rq_flags rf; +- struct rq *rq; +- +- rq = task_rq_lock(t, &rf); +- ns = t->se.sum_exec_runtime; +- task_rq_unlock(rq, t, &rf); +- +- return ns; +-} +-#endif +- + /* + * Accumulate raw cputime values of dead tasks (sig->[us]time) and live + * tasks (sum on group iteration) belonging to @tsk's group. +@@ -662,7 +642,7 @@ + void task_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st) + { + struct task_cputime cputime = { +- .sum_exec_runtime = p->se.sum_exec_runtime, ++ .sum_exec_runtime = tsk_seruntime(p), + }; + + task_cputime(p, &cputime.utime, &cputime.stime); +diff -Nur a/kernel/sched/idle.c b/kernel/sched/idle.c +--- a/kernel/sched/idle.c 2019-02-06 16:30:16.000000000 +0000 ++++ b/kernel/sched/idle.c 2019-02-09 17:46:12.001297867 +0000 +@@ -224,6 +224,8 @@ + static void do_idle(void) + { + int cpu = smp_processor_id(); ++ bool pending = false; ++ + /* + * If the arch has a polling bit, we maintain an invariant: + * +@@ -234,7 +236,10 @@ + */ + + __current_set_polling(); +- tick_nohz_idle_enter(); ++ if (unlikely(softirq_pending(cpu))) ++ pending = true; ++ else ++ tick_nohz_idle_enter(); + + while (!need_resched()) { + check_pgt_cache(); +@@ -272,7 +277,8 @@ + * an IPI to fold the state for us. + */ + preempt_set_need_resched(); +- tick_nohz_idle_exit(); ++ if (!pending) ++ tick_nohz_idle_exit(); + __current_clr_polling(); + + /* +@@ -368,6 +374,7 @@ + do_idle(); + } + ++#ifndef CONFIG_SCHED_MUQSS + /* + * idle-task scheduling class. + */ +@@ -480,3 +487,4 @@ + .switched_to = switched_to_idle, + .update_curr = update_curr_idle, + }; ++#endif /* CONFIG_SCHED_MUQSS */ +diff -Nur a/kernel/sched/Makefile b/kernel/sched/Makefile +--- a/kernel/sched/Makefile 2019-02-06 16:30:16.000000000 +0000 ++++ b/kernel/sched/Makefile 2019-02-09 17:46:11.991297545 +0000 +@@ -16,6 +16,17 @@ + CFLAGS_core.o := $(PROFILING) -fno-omit-frame-pointer + endif + ++ifdef CONFIG_SCHED_MUQSS ++obj-y += MuQSS.o clock.o cputime.o ++obj-y += idle.o ++obj-y += wait.o wait_bit.o swait.o completion.o ++ ++obj-$(CONFIG_SMP) += topology.o ++obj-$(CONFIG_SCHEDSTATS) += stats.o ++obj-$(CONFIG_CPU_FREQ) += cpufreq.o ++obj-$(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) += cpufreq_schedutil.o ++obj-$(CONFIG_CPU_ISOLATION) += isolation.o ++else + obj-y += core.o loadavg.o clock.o cputime.o + obj-y += idle.o fair.o rt.o deadline.o + obj-y += wait.o wait_bit.o swait.o completion.o +@@ -29,3 +40,4 @@ + obj-$(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) += cpufreq_schedutil.o + obj-$(CONFIG_MEMBARRIER) += membarrier.o + obj-$(CONFIG_CPU_ISOLATION) += isolation.o ++endif +diff -Nur a/kernel/sched/MuQSS.c b/kernel/sched/MuQSS.c +--- a/kernel/sched/MuQSS.c 1970-01-01 01:00:00.000000000 +0100 ++++ b/kernel/sched/MuQSS.c 2019-02-09 17:46:12.001297867 +0000 +@@ -0,0 +1,7366 @@ ++// SPDX-License-Identifier: GPL-2.0 ++/* ++ * kernel/sched/MuQSS.c, was kernel/sched.c ++ * ++ * Kernel scheduler and related syscalls ++ * ++ * Copyright (C) 1991-2002 Linus Torvalds ++ * ++ * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and ++ * make semaphores SMP safe ++ * 1998-11-19 Implemented schedule_timeout() and related stuff ++ * by Andrea Arcangeli ++ * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar: ++ * hybrid priority-list and round-robin design with ++ * an array-switch method of distributing timeslices ++ * and per-CPU runqueues. Cleanups and useful suggestions ++ * by Davide Libenzi, preemptible kernel bits by Robert Love. ++ * 2003-09-03 Interactivity tuning by Con Kolivas. ++ * 2004-04-02 Scheduler domains code by Nick Piggin ++ * 2007-04-15 Work begun on replacing all interactivity tuning with a ++ * fair scheduling design by Con Kolivas. ++ * 2007-05-05 Load balancing (smp-nice) and other improvements ++ * by Peter Williams ++ * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith ++ * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri ++ * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins, ++ * Thomas Gleixner, Mike Kravetz ++ * 2009-08-13 Brainfuck deadline scheduling policy by Con Kolivas deletes ++ * a whole lot of those previous things. ++ * 2016-10-01 Multiple Queue Skiplist Scheduler scalable evolution of BFS ++ * scheduler by Con Kolivas. ++ */ ++ ++#include <linux/sched/isolation.h> ++#include <linux/sched/loadavg.h> ++ ++#include <linux/binfmts.h> ++#include <linux/blkdev.h> ++#include <linux/compat.h> ++#include <linux/context_tracking.h> ++#include <linux/cpuset.h> ++#include <linux/delayacct.h> ++#include <linux/init_task.h> ++#include <linux/kcov.h> ++#include <linux/kprobes.h> ++#include <linux/mmu_context.h> ++#include <linux/module.h> ++#include <linux/nmi.h> ++#include <linux/prefetch.h> ++#include <linux/profile.h> ++#include <linux/rcupdate_wait.h> ++#include <linux/sched.h> ++#include <linux/security.h> ++#include <linux/skip_list.h> ++#include <linux/syscalls.h> ++#include <linux/tick.h> ++#include <linux/wait_bit.h> ++ ++#include <asm/irq_regs.h> ++#include <asm/switch_to.h> ++#include <asm/tlb.h> ++ ++#include "../workqueue_internal.h" ++#include "../smpboot.h" ++ ++#define CREATE_TRACE_POINTS ++#include <trace/events/sched.h> ++ ++#include "MuQSS.h" ++ ++#define rt_prio(prio) unlikely((prio) < MAX_RT_PRIO) ++#define rt_task(p) rt_prio((p)->prio) ++#define batch_task(p) (unlikely((p)->policy == SCHED_BATCH)) ++#define is_rt_policy(policy) ((policy) == SCHED_FIFO || \ ++ (policy) == SCHED_RR) ++#define has_rt_policy(p) unlikely(is_rt_policy((p)->policy)) ++ ++#define is_idle_policy(policy) ((policy) == SCHED_IDLEPRIO) ++#define idleprio_task(p) unlikely(is_idle_policy((p)->policy)) ++#define task_running_idle(p) unlikely((p)->prio == IDLE_PRIO) ++ ++#define is_iso_policy(policy) ((policy) == SCHED_ISO) ++#define iso_task(p) unlikely(is_iso_policy((p)->policy)) ++#define task_running_iso(p) unlikely((p)->prio == ISO_PRIO) ++ ++#define rq_idle(rq) ((rq)->rq_prio == PRIO_LIMIT) ++ ++#define ISO_PERIOD (5 * HZ) ++ ++#define STOP_PRIO (MAX_RT_PRIO - 1) ++ ++/* ++ * Some helpers for converting to/from various scales. Use shifts to get ++ * approximate multiples of ten for less overhead. ++ */ ++#define APPROX_NS_PS (1073741824) /* Approximate ns per second */ ++#define JIFFIES_TO_NS(TIME) ((TIME) * (APPROX_NS_PS / HZ)) ++#define JIFFY_NS (APPROX_NS_PS / HZ) ++#define JIFFY_US (1048576 / HZ) ++#define NS_TO_JIFFIES(TIME) ((TIME) / JIFFY_NS) ++#define HALF_JIFFY_NS (APPROX_NS_PS / HZ / 2) ++#define HALF_JIFFY_US (1048576 / HZ / 2) ++#define MS_TO_NS(TIME) ((TIME) << 20) ++#define MS_TO_US(TIME) ((TIME) << 10) ++#define NS_TO_MS(TIME) ((TIME) >> 20) ++#define NS_TO_US(TIME) ((TIME) >> 10) ++#define US_TO_NS(TIME) ((TIME) << 10) ++#define TICK_APPROX_NS ((APPROX_NS_PS+HZ/2)/HZ) ++ ++#define RESCHED_US (100) /* Reschedule if less than this many μs left */ ++ ++void print_scheduler_version(void) ++{ ++ printk(KERN_INFO "MuQSS CPU scheduler v0.180 by Con Kolivas.\n"); ++} ++ ++#define RQSHARE_NONE 0 ++#define RQSHARE_SMT 1 ++#define RQSHARE_MC 2 ++#define RQSHARE_SMP 3 ++ ++/* ++ * This determines what level of runqueue sharing will be done and is ++ * configurable at boot time with the bootparam rqshare = ++ */ ++static int rqshare __read_mostly = CONFIG_SHARERQ; /* Default RQSHARE_MC */ ++ ++static int __init set_rqshare(char *str) ++{ ++ if (!strncmp(str, "none", 4)) { ++ rqshare = RQSHARE_NONE; ++ return 0; ++ } ++ if (!strncmp(str, "smt", 3)) { ++ rqshare = RQSHARE_SMT; ++ return 0; ++ } ++ if (!strncmp(str, "mc", 2)) { ++ rqshare = RQSHARE_MC; ++ return 0; ++ } ++ if (!strncmp(str, "smp", 2)) { ++ rqshare = RQSHARE_SMP; ++ return 0; ++ } ++ return 1; ++} ++__setup("rqshare=", set_rqshare); ++ ++/* ++ * This is the time all tasks within the same priority round robin. ++ * Value is in ms and set to a minimum of 6ms. ++ * Tunable via /proc interface. ++ */ ++int rr_interval __read_mostly = 6; ++ ++/* ++ * Tunable to choose whether to prioritise latency or throughput, simple ++ * binary yes or no ++ */ ++int sched_interactive __read_mostly = 1; ++ ++/* ++ * sched_iso_cpu - sysctl which determines the cpu percentage SCHED_ISO tasks ++ * are allowed to run five seconds as real time tasks. This is the total over ++ * all online cpus. ++ */ ++int sched_iso_cpu __read_mostly = 70; ++ ++/* ++ * sched_yield_type - Choose what sort of yield sched_yield will perform. ++ * 0: No yield. ++ * 1: Yield only to better priority/deadline tasks. (default) ++ * 2: Expire timeslice and recalculate deadline. ++ */ ++int sched_yield_type __read_mostly = 1; ++ ++/* ++ * The relative length of deadline for each priority(nice) level. ++ */ ++static int prio_ratios[NICE_WIDTH] __read_mostly; ++ ++ ++/* ++ * The quota handed out to tasks of all priority levels when refilling their ++ * time_slice. ++ */ ++static inline int timeslice(void) ++{ ++ return MS_TO_US(rr_interval); ++} ++ ++DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); ++ ++#ifdef CONFIG_SMP ++/* ++ * Total number of runqueues. Equals number of CPUs when there is no runqueue ++ * sharing but is usually less with SMT/MC sharing of runqueues. ++ */ ++static int total_runqueues __read_mostly = 1; ++ ++static cpumask_t cpu_idle_map ____cacheline_aligned_in_smp; ++ ++struct rq *cpu_rq(int cpu) ++{ ++ return &per_cpu(runqueues, (cpu)); ++} ++#define cpu_curr(cpu) (cpu_rq(cpu)->curr) ++ ++/* ++ * For asym packing, by default the lower numbered cpu has higher priority. ++ */ ++int __weak arch_asym_cpu_priority(int cpu) ++{ ++ return -cpu; ++} ++ ++int __weak arch_sd_sibling_asym_packing(void) ++{ ++ return 0*SD_ASYM_PACKING; ++} ++#else ++struct rq *uprq; ++#endif /* CONFIG_SMP */ ++ ++#include "stats.h" ++ ++/* ++ * All common locking functions performed on rq->lock. rq->clock is local to ++ * the CPU accessing it so it can be modified just with interrupts disabled ++ * when we're not updating niffies. ++ * Looking up task_rq must be done under rq->lock to be safe. ++ */ ++ ++/* ++ * RQ-clock updating methods: ++ */ ++ ++#ifdef HAVE_SCHED_AVG_IRQ ++static void update_irq_load_avg(struct rq *rq, long delta); ++#else ++static inline void update_irq_load_avg(struct rq *rq, long delta) {} ++#endif ++ ++static void update_rq_clock_task(struct rq *rq, s64 delta) ++{ ++/* ++ * In theory, the compile should just see 0 here, and optimize out the call ++ * to sched_rt_avg_update. But I don't trust it... ++ */ ++#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) ++ s64 steal = 0, irq_delta = 0; ++#endif ++#ifdef CONFIG_IRQ_TIME_ACCOUNTING ++ irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time; ++ ++ /* ++ * Since irq_time is only updated on {soft,}irq_exit, we might run into ++ * this case when a previous update_rq_clock() happened inside a ++ * {soft,}irq region. ++ * ++ * When this happens, we stop ->clock_task and only update the ++ * prev_irq_time stamp to account for the part that fit, so that a next ++ * update will consume the rest. This ensures ->clock_task is ++ * monotonic. ++ * ++ * It does however cause some slight miss-attribution of {soft,}irq ++ * time, a more accurate solution would be to update the irq_time using ++ * the current rq->clock timestamp, except that would require using ++ * atomic ops. ++ */ ++ if (irq_delta > delta) ++ irq_delta = delta; ++ ++ rq->prev_irq_time += irq_delta; ++ delta -= irq_delta; ++#endif ++#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING ++ if (static_key_false((¶virt_steal_rq_enabled))) { ++ steal = paravirt_steal_clock(cpu_of(rq)); ++ steal -= rq->prev_steal_time_rq; ++ ++ if (unlikely(steal > delta)) ++ steal = delta; ++ ++ rq->prev_steal_time_rq += steal; ++ delta -= steal; ++ } ++#endif ++ rq->clock_task += delta; ++ ++#ifdef HAVE_SCHED_AVG_IRQ ++ if (irq_delta + steal) ++ update_irq_load_avg(rq, irq_delta + steal); ++#endif ++} ++ ++static inline void update_rq_clock(struct rq *rq) ++{ ++ s64 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock; ++ ++ if (unlikely(delta < 0)) ++ return; ++ rq->clock += delta; ++ update_rq_clock_task(rq, delta); ++} ++ ++/* ++ * Niffies are a globally increasing nanosecond counter. They're only used by ++ * update_load_avg and time_slice_expired, however deadlines are based on them ++ * across CPUs. Update them whenever we will call one of those functions, and ++ * synchronise them across CPUs whenever we hold both runqueue locks. ++ */ ++static inline void update_clocks(struct rq *rq) ++{ ++ s64 ndiff, minndiff; ++ long jdiff; ++ ++ update_rq_clock(rq); ++ ndiff = rq->clock - rq->old_clock; ++ rq->old_clock = rq->clock; ++ jdiff = jiffies - rq->last_jiffy; ++ ++ /* Subtract any niffies added by balancing with other rqs */ ++ ndiff -= rq->niffies - rq->last_niffy; ++ minndiff = JIFFIES_TO_NS(jdiff) - rq->niffies + rq->last_jiffy_niffies; ++ if (minndiff < 0) ++ minndiff = 0; ++ ndiff = max(ndiff, minndiff); ++ rq->niffies += ndiff; ++ rq->last_niffy = rq->niffies; ++ if (jdiff) { ++ rq->last_jiffy += jdiff; ++ rq->last_jiffy_niffies = rq->niffies; ++ } ++} ++ ++static inline int task_on_rq_queued(struct task_struct *p) ++{ ++ return p->on_rq == TASK_ON_RQ_QUEUED; ++} ++ ++static inline int task_on_rq_migrating(struct task_struct *p) ++{ ++ return p->on_rq == TASK_ON_RQ_MIGRATING; ++} ++ ++/* ++ * Any time we have two runqueues locked we use that as an opportunity to ++ * synchronise niffies to the highest value as idle ticks may have artificially ++ * kept niffies low on one CPU and the truth can only be later. ++ */ ++static inline void synchronise_niffies(struct rq *rq1, struct rq *rq2) ++{ ++ if (rq1->niffies > rq2->niffies) ++ rq2->niffies = rq1->niffies; ++ else ++ rq1->niffies = rq2->niffies; ++} ++ ++/* ++ * double_rq_lock - safely lock two runqueues ++ * ++ * Note this does not disable interrupts like task_rq_lock, ++ * you need to do so manually before calling. ++ */ ++ ++/* For when we know rq1 != rq2 */ ++static inline void __double_rq_lock(struct rq *rq1, struct rq *rq2) ++ __acquires(rq1->lock) ++ __acquires(rq2->lock) ++{ ++ if (rq1 < rq2) { ++ raw_spin_lock(rq1->lock); ++ raw_spin_lock_nested(rq2->lock, SINGLE_DEPTH_NESTING); ++ } else { ++ raw_spin_lock(rq2->lock); ++ raw_spin_lock_nested(rq1->lock, SINGLE_DEPTH_NESTING); ++ } ++} ++ ++static inline void double_rq_lock(struct rq *rq1, struct rq *rq2) ++ __acquires(rq1->lock) ++ __acquires(rq2->lock) ++{ ++ BUG_ON(!irqs_disabled()); ++ if (rq1->lock == rq2->lock) { ++ raw_spin_lock(rq1->lock); ++ __acquire(rq2->lock); /* Fake it out ;) */ ++ } else ++ __double_rq_lock(rq1, rq2); ++ synchronise_niffies(rq1, rq2); ++} ++ ++/* ++ * double_rq_unlock - safely unlock two runqueues ++ * ++ * Note this does not restore interrupts like task_rq_unlock, ++ * you need to do so manually after calling. ++ */ ++static inline void double_rq_unlock(struct rq *rq1, struct rq *rq2) ++ __releases(rq1->lock) ++ __releases(rq2->lock) ++{ ++ raw_spin_unlock(rq1->lock); ++ if (rq1->lock != rq2->lock) ++ raw_spin_unlock(rq2->lock); ++ else ++ __release(rq2->lock); ++} ++ ++static inline void lock_all_rqs(void) ++{ ++ int cpu; ++ ++ preempt_disable(); ++ for_each_possible_cpu(cpu) { ++ struct rq *rq = cpu_rq(cpu); ++ ++ do_raw_spin_lock(rq->lock); ++ } ++} ++ ++static inline void unlock_all_rqs(void) ++{ ++ int cpu; ++ ++ for_each_possible_cpu(cpu) { ++ struct rq *rq = cpu_rq(cpu); ++ ++ do_raw_spin_unlock(rq->lock); ++ } ++ preempt_enable(); ++} ++ ++/* Specially nest trylock an rq */ ++static inline bool trylock_rq(struct rq *this_rq, struct rq *rq) ++{ ++ if (unlikely(!do_raw_spin_trylock(rq->lock))) ++ return false; ++ spin_acquire(rq->lock.dep_map, SINGLE_DEPTH_NESTING, 1, _RET_IP_); ++ synchronise_niffies(this_rq, rq); ++ return true; ++} ++ ++/* Unlock a specially nested trylocked rq */ ++static inline void unlock_rq(struct rq *rq) ++{ ++ spin_release(rq->lock.dep_map, 1, _RET_IP_); ++ do_raw_spin_unlock(rq->lock); ++} ++ ++/* ++ * cmpxchg based fetch_or, macro so it works for different integer types ++ */ ++#define fetch_or(ptr, mask) \ ++ ({ \ ++ typeof(ptr) _ptr = (ptr); \ ++ typeof(mask) _mask = (mask); \ ++ typeof(*_ptr) _old, _val = *_ptr; \ ++ \ ++ for (;;) { \ ++ _old = cmpxchg(_ptr, _val, _val | _mask); \ ++ if (_old == _val) \ ++ break; \ ++ _val = _old; \ ++ } \ ++ _old; \ ++}) ++ ++#if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG) ++/* ++ * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG, ++ * this avoids any races wrt polling state changes and thereby avoids ++ * spurious IPIs. ++ */ ++static bool set_nr_and_not_polling(struct task_struct *p) ++{ ++ struct thread_info *ti = task_thread_info(p); ++ return !(fetch_or(&ti->flags, _TIF_NEED_RESCHED) & _TIF_POLLING_NRFLAG); ++} ++ ++/* ++ * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set. ++ * ++ * If this returns true, then the idle task promises to call ++ * sched_ttwu_pending() and reschedule soon. ++ */ ++static bool set_nr_if_polling(struct task_struct *p) ++{ ++ struct thread_info *ti = task_thread_info(p); ++ typeof(ti->flags) old, val = READ_ONCE(ti->flags); ++ ++ for (;;) { ++ if (!(val & _TIF_POLLING_NRFLAG)) ++ return false; ++ if (val & _TIF_NEED_RESCHED) ++ return true; ++ old = cmpxchg(&ti->flags, val, val | _TIF_NEED_RESCHED); ++ if (old == val) ++ break; ++ val = old; ++ } ++ return true; ++} ++ ++#else ++static bool set_nr_and_not_polling(struct task_struct *p) ++{ ++ set_tsk_need_resched(p); ++ return true; ++} ++ ++#ifdef CONFIG_SMP ++static bool set_nr_if_polling(struct task_struct *p) ++{ ++ return false; ++} ++#endif ++#endif ++ ++void wake_q_add(struct wake_q_head *head, struct task_struct *task) ++{ ++ struct wake_q_node *node = &task->wake_q; ++ ++ /* ++ * Atomically grab the task, if ->wake_q is !nil already it means ++ * its already queued (either by us or someone else) and will get the ++ * wakeup due to that. ++ * ++ * This cmpxchg() executes a full barrier, which pairs with the full ++ * barrier executed by the wakeup in wake_up_q(). ++ */ ++ if (cmpxchg(&node->next, NULL, WAKE_Q_TAIL)) ++ return; ++ ++ get_task_struct(task); ++ ++ /* ++ * The head is context local, there can be no concurrency. ++ */ ++ *head->lastp = node; ++ head->lastp = &node->next; ++} ++ ++void wake_up_q(struct wake_q_head *head) ++{ ++ struct wake_q_node *node = head->first; ++ ++ while (node != WAKE_Q_TAIL) { ++ struct task_struct *task; ++ ++ task = container_of(node, struct task_struct, wake_q); ++ BUG_ON(!task); ++ /* Task can safely be re-inserted now */ ++ node = node->next; ++ task->wake_q.next = NULL; ++ ++ /* ++ * wake_up_process() executes a full barrier, which pairs with ++ * the queueing in wake_q_add() so as not to miss wakeups. ++ */ ++ wake_up_process(task); ++ put_task_struct(task); ++ } ++} ++ ++static inline void smp_sched_reschedule(int cpu) ++{ ++ if (likely(cpu_online(cpu))) ++ smp_send_reschedule(cpu); ++} ++ ++/* ++ * resched_task - mark a task 'to be rescheduled now'. ++ * ++ * On UP this means the setting of the need_resched flag, on SMP it ++ * might also involve a cross-CPU call to trigger the scheduler on ++ * the target CPU. ++ */ ++void resched_task(struct task_struct *p) ++{ ++ int cpu; ++#ifdef CONFIG_LOCKDEP ++ /* Kernel threads call this when creating workqueues while still ++ * inactive from __kthread_bind_mask, holding only the pi_lock */ ++ if (!(p->flags & PF_KTHREAD)) { ++ struct rq *rq = task_rq(p); ++ ++ lockdep_assert_held(rq->lock); ++ } ++#endif ++ if (test_tsk_need_resched(p)) ++ return; ++ ++ cpu = task_cpu(p); ++ if (cpu == smp_processor_id()) { ++ set_tsk_need_resched(p); ++ set_preempt_need_resched(); ++ return; ++ } ++ ++ if (set_nr_and_not_polling(p)) ++ smp_sched_reschedule(cpu); ++ else ++ trace_sched_wake_idle_without_ipi(cpu); ++} ++ ++/* ++ * A task that is not running or queued will not have a node set. ++ * A task that is queued but not running will have a node set. ++ * A task that is currently running will have ->on_cpu set but no node set. ++ */ ++static inline bool task_queued(struct task_struct *p) ++{ ++ return !skiplist_node_empty(&p->node); ++} ++ ++static void enqueue_task(struct rq *rq, struct task_struct *p, int flags); ++static inline void resched_if_idle(struct rq *rq); ++ ++/* Dodgy workaround till we figure out where the softirqs are going */ ++static inline void do_pending_softirq(struct rq *rq, struct task_struct *next) ++{ ++ if (unlikely(next == rq->idle && local_softirq_pending() && !in_interrupt())) ++ do_softirq_own_stack(); ++} ++ ++static inline bool deadline_before(u64 deadline, u64 time) ++{ ++ return (deadline < time); ++} ++ ++/* ++ * Deadline is "now" in niffies + (offset by priority). Setting the deadline ++ * is the key to everything. It distributes cpu fairly amongst tasks of the ++ * same nice value, it proportions cpu according to nice level, it means the ++ * task that last woke up the longest ago has the earliest deadline, thus ++ * ensuring that interactive tasks get low latency on wake up. The CPU ++ * proportion works out to the square of the virtual deadline difference, so ++ * this equation will give nice 19 3% CPU compared to nice 0. ++ */ ++static inline u64 prio_deadline_diff(int user_prio) ++{ ++ return (prio_ratios[user_prio] * rr_interval * (MS_TO_NS(1) / 128)); ++} ++ ++static inline u64 task_deadline_diff(struct task_struct *p) ++{ ++ return prio_deadline_diff(TASK_USER_PRIO(p)); ++} ++ ++static inline u64 static_deadline_diff(int static_prio) ++{ ++ return prio_deadline_diff(USER_PRIO(static_prio)); ++} ++ ++static inline int longest_deadline_diff(void) ++{ ++ return prio_deadline_diff(39); ++} ++ ++static inline int ms_longest_deadline_diff(void) ++{ ++ return NS_TO_MS(longest_deadline_diff()); ++} ++ ++static inline bool rq_local(struct rq *rq); ++ ++#ifndef SCHED_CAPACITY_SCALE ++#define SCHED_CAPACITY_SCALE 1024 ++#endif ++ ++static inline int rq_load(struct rq *rq) ++{ ++ return rq->nr_running; ++} ++ ++/* ++ * Update the load average for feeding into cpu frequency governors. Use a ++ * rough estimate of a rolling average with ~ time constant of 32ms. ++ * 80/128 ~ 0.63. * 80 / 32768 / 128 == * 5 / 262144 ++ * Make sure a call to update_clocks has been made before calling this to get ++ * an updated rq->niffies. ++ */ ++static void update_load_avg(struct rq *rq, unsigned int flags) ++{ ++ long us_interval, load; ++ unsigned long curload; ++ ++ us_interval = NS_TO_US(rq->niffies - rq->load_update); ++ if (unlikely(us_interval <= 0)) ++ return; ++ ++ curload = rq_load(rq); ++ load = rq->load_avg - (rq->load_avg * us_interval * 5 / 262144); ++ if (unlikely(load < 0)) ++ load = 0; ++ load += curload * curload * SCHED_CAPACITY_SCALE * us_interval * 5 / 262144; ++ rq->load_avg = load; ++ ++ rq->load_update = rq->niffies; ++ update_irq_load_avg(rq, 0); ++ if (likely(rq_local(rq))) ++ cpufreq_trigger(rq, flags); ++} ++ ++#ifdef HAVE_SCHED_AVG_IRQ ++/* ++ * IRQ variant of update_load_avg below. delta is actually time in nanoseconds ++ * here so we scale curload to how long it's been since the last update. ++ */ ++static void update_irq_load_avg(struct rq *rq, long delta) ++{ ++ long us_interval, load; ++ unsigned long curload; ++ ++ us_interval = NS_TO_US(rq->niffies - rq->irq_load_update); ++ if (unlikely(us_interval <= 0)) ++ return; ++ ++ curload = NS_TO_US(delta) / us_interval; ++ load = rq->irq_load_avg - (rq->irq_load_avg * us_interval * 5 / 262144); ++ if (unlikely(load < 0)) ++ load = 0; ++ load += curload * curload * SCHED_CAPACITY_SCALE * us_interval * 5 / 262144; ++ rq->irq_load_avg = load; ++ ++ rq->irq_load_update = rq->niffies; ++} ++#endif ++ ++/* ++ * Removing from the runqueue. Enter with rq locked. Deleting a task ++ * from the skip list is done via the stored node reference in the task struct ++ * and does not require a full look up. Thus it occurs in O(k) time where k ++ * is the "level" of the list the task was stored at - usually < 4, max 8. ++ */ ++static void dequeue_task(struct rq *rq, struct task_struct *p, int flags) ++{ ++ skiplist_delete(rq->sl, &p->node); ++ rq->best_key = rq->node->next[0]->key; ++ update_clocks(rq); ++ ++ if (!(flags & DEQUEUE_SAVE)) ++ sched_info_dequeued(task_rq(p), p); ++ rq->nr_running--; ++ if (rt_task(p)) ++ rq->rt_nr_running--; ++ update_load_avg(rq, flags); ++} ++ ++#ifdef CONFIG_PREEMPT_RCU ++static bool rcu_read_critical(struct task_struct *p) ++{ ++ return p->rcu_read_unlock_special.b.blocked; ++} ++#else /* CONFIG_PREEMPT_RCU */ ++#define rcu_read_critical(p) (false) ++#endif /* CONFIG_PREEMPT_RCU */ ++ ++/* ++ * To determine if it's safe for a task of SCHED_IDLEPRIO to actually run as ++ * an idle task, we ensure none of the following conditions are met. ++ */ ++static bool idleprio_suitable(struct task_struct *p) ++{ ++ return (!(task_contributes_to_load(p)) && !(p->flags & (PF_EXITING)) && ++ !signal_pending(p) && !rcu_read_critical(p) && !freezing(p)); ++} ++ ++/* ++ * To determine if a task of SCHED_ISO can run in pseudo-realtime, we check ++ * that the iso_refractory flag is not set. ++ */ ++static inline bool isoprio_suitable(struct rq *rq) ++{ ++ return !rq->iso_refractory; ++} ++ ++/* ++ * Adding to the runqueue. Enter with rq locked. ++ */ ++static void enqueue_task(struct rq *rq, struct task_struct *p, int flags) ++{ ++ unsigned int randseed, cflags = 0; ++ u64 sl_id; ++ ++ if (!rt_task(p)) { ++ /* Check it hasn't gotten rt from PI */ ++ if ((idleprio_task(p) && idleprio_suitable(p)) || ++ (iso_task(p) && isoprio_suitable(rq))) ++ p->prio = p->normal_prio; ++ else ++ p->prio = NORMAL_PRIO; ++ } else ++ rq->rt_nr_running++; ++ /* ++ * The sl_id key passed to the skiplist generates a sorted list. ++ * Realtime and sched iso tasks run FIFO so they only need be sorted ++ * according to priority. The skiplist will put tasks of the same ++ * key inserted later in FIFO order. Tasks of sched normal, batch ++ * and idleprio are sorted according to their deadlines. Idleprio ++ * tasks are offset by an impossibly large deadline value ensuring ++ * they get sorted into last positions, but still according to their ++ * own deadlines. This creates a "landscape" of skiplists running ++ * from priority 0 realtime in first place to the lowest priority ++ * idleprio tasks last. Skiplist insertion is an O(log n) process. ++ */ ++ if (p->prio <= ISO_PRIO) { ++ sl_id = p->prio; ++ } else { ++ sl_id = p->deadline; ++ if (idleprio_task(p)) { ++ if (p->prio == IDLE_PRIO) ++ sl_id |= 0xF000000000000000; ++ else ++ sl_id += longest_deadline_diff(); ++ } ++ } ++ /* ++ * Some architectures don't have better than microsecond resolution ++ * so mask out ~microseconds as the random seed for skiplist insertion. ++ */ ++ update_clocks(rq); ++ if (!(flags & ENQUEUE_RESTORE)) ++ sched_info_queued(rq, p); ++ randseed = (rq->niffies >> 10) & 0xFFFFFFFF; ++ skiplist_insert(rq->sl, &p->node, sl_id, p, randseed); ++ rq->best_key = rq->node->next[0]->key; ++ if (p->in_iowait) ++ cflags |= SCHED_CPUFREQ_IOWAIT; ++ rq->nr_running++; ++ update_load_avg(rq, cflags); ++} ++ ++/* ++ * Returns the relative length of deadline all compared to the shortest ++ * deadline which is that of nice -20. ++ */ ++static inline int task_prio_ratio(struct task_struct *p) ++{ ++ return prio_ratios[TASK_USER_PRIO(p)]; ++} ++ ++/* ++ * task_timeslice - all tasks of all priorities get the exact same timeslice ++ * length. CPU distribution is handled by giving different deadlines to ++ * tasks of different priorities. Use 128 as the base value for fast shifts. ++ */ ++static inline int task_timeslice(struct task_struct *p) ++{ ++ return (rr_interval * task_prio_ratio(p) / 128); ++} ++ ++#ifdef CONFIG_SMP ++/* Entered with rq locked */ ++static inline void resched_if_idle(struct rq *rq) ++{ ++ if (rq_idle(rq)) ++ resched_task(rq->curr); ++} ++ ++static inline bool rq_local(struct rq *rq) ++{ ++ return (rq->cpu == smp_processor_id()); ++} ++#ifdef CONFIG_SMT_NICE ++static const cpumask_t *thread_cpumask(int cpu); ++ ++/* Find the best real time priority running on any SMT siblings of cpu and if ++ * none are running, the static priority of the best deadline task running. ++ * The lookups to the other runqueues is done lockless as the occasional wrong ++ * value would be harmless. */ ++static int best_smt_bias(struct rq *this_rq) ++{ ++ int other_cpu, best_bias = 0; ++ ++ for_each_cpu(other_cpu, &this_rq->thread_mask) { ++ struct rq *rq = cpu_rq(other_cpu); ++ ++ if (rq_idle(rq)) ++ continue; ++ if (unlikely(!rq->online)) ++ continue; ++ if (!rq->rq_mm) ++ continue; ++ if (likely(rq->rq_smt_bias > best_bias)) ++ best_bias = rq->rq_smt_bias; ++ } ++ return best_bias; ++} ++ ++static int task_prio_bias(struct task_struct *p) ++{ ++ if (rt_task(p)) ++ return 1 << 30; ++ else if (task_running_iso(p)) ++ return 1 << 29; ++ else if (task_running_idle(p)) ++ return 0; ++ return MAX_PRIO - p->static_prio; ++} ++ ++static bool smt_always_schedule(struct task_struct __maybe_unused *p, struct rq __maybe_unused *this_rq) ++{ ++ return true; ++} ++ ++static bool (*smt_schedule)(struct task_struct *p, struct rq *this_rq) = &smt_always_schedule; ++ ++/* We've already decided p can run on CPU, now test if it shouldn't for SMT ++ * nice reasons. */ ++static bool smt_should_schedule(struct task_struct *p, struct rq *this_rq) ++{ ++ int best_bias, task_bias; ++ ++ /* Kernel threads always run */ ++ if (unlikely(!p->mm)) ++ return true; ++ if (rt_task(p)) ++ return true; ++ if (!idleprio_suitable(p)) ++ return true; ++ best_bias = best_smt_bias(this_rq); ++ /* The smt siblings are all idle or running IDLEPRIO */ ++ if (best_bias < 1) ++ return true; ++ task_bias = task_prio_bias(p); ++ if (task_bias < 1) ++ return false; ++ if (task_bias >= best_bias) ++ return true; ++ /* Dither 25% cpu of normal tasks regardless of nice difference */ ++ if (best_bias % 4 == 1) ++ return true; ++ /* Sorry, you lose */ ++ return false; ++} ++#else /* CONFIG_SMT_NICE */ ++#define smt_schedule(p, this_rq) (true) ++#endif /* CONFIG_SMT_NICE */ ++ ++static inline void atomic_set_cpu(int cpu, cpumask_t *cpumask) ++{ ++ set_bit(cpu, (volatile unsigned long *)cpumask); ++} ++ ++/* ++ * The cpu_idle_map stores a bitmap of all the CPUs currently idle to ++ * allow easy lookup of whether any suitable idle CPUs are available. ++ * It's cheaper to maintain a binary yes/no if there are any idle CPUs on the ++ * idle_cpus variable than to do a full bitmask check when we are busy. The ++ * bits are set atomically but read locklessly as occasional false positive / ++ * negative is harmless. ++ */ ++static inline void set_cpuidle_map(int cpu) ++{ ++ if (likely(cpu_online(cpu))) ++ atomic_set_cpu(cpu, &cpu_idle_map); ++} ++ ++static inline void atomic_clear_cpu(int cpu, cpumask_t *cpumask) ++{ ++ clear_bit(cpu, (volatile unsigned long *)cpumask); ++} ++ ++static inline void clear_cpuidle_map(int cpu) ++{ ++ atomic_clear_cpu(cpu, &cpu_idle_map); ++} ++ ++static bool suitable_idle_cpus(struct task_struct *p) ++{ ++ return (cpumask_intersects(&p->cpus_allowed, &cpu_idle_map)); ++} ++ ++/* ++ * Resched current on rq. We don't know if rq is local to this CPU nor if it ++ * is locked so we do not use an intermediate variable for the task to avoid ++ * having it dereferenced. ++ */ ++static void resched_curr(struct rq *rq) ++{ ++ int cpu; ++ ++ if (test_tsk_need_resched(rq->curr)) ++ return; ++ ++ rq->preempt = rq->curr; ++ cpu = rq->cpu; ++ ++ /* We're doing this without holding the rq lock if it's not task_rq */ ++ ++ if (cpu == smp_processor_id()) { ++ set_tsk_need_resched(rq->curr); ++ set_preempt_need_resched(); ++ return; ++ } ++ ++ if (set_nr_and_not_polling(rq->curr)) ++ smp_sched_reschedule(cpu); ++ else ++ trace_sched_wake_idle_without_ipi(cpu); ++} ++ ++#define CPUIDLE_DIFF_THREAD (1) ++#define CPUIDLE_DIFF_CORE (2) ++#define CPUIDLE_CACHE_BUSY (4) ++#define CPUIDLE_DIFF_CPU (8) ++#define CPUIDLE_THREAD_BUSY (16) ++#define CPUIDLE_DIFF_NODE (32) ++ ++/* ++ * The best idle CPU is chosen according to the CPUIDLE ranking above where the ++ * lowest value would give the most suitable CPU to schedule p onto next. The ++ * order works out to be the following: ++ * ++ * Same thread, idle or busy cache, idle or busy threads ++ * Other core, same cache, idle or busy cache, idle threads. ++ * Same node, other CPU, idle cache, idle threads. ++ * Same node, other CPU, busy cache, idle threads. ++ * Other core, same cache, busy threads. ++ * Same node, other CPU, busy threads. ++ * Other node, other CPU, idle cache, idle threads. ++ * Other node, other CPU, busy cache, idle threads. ++ * Other node, other CPU, busy threads. ++ */ ++static int best_mask_cpu(int best_cpu, struct rq *rq, cpumask_t *tmpmask) ++{ ++ int best_ranking = CPUIDLE_DIFF_NODE | CPUIDLE_THREAD_BUSY | ++ CPUIDLE_DIFF_CPU | CPUIDLE_CACHE_BUSY | CPUIDLE_DIFF_CORE | ++ CPUIDLE_DIFF_THREAD; ++ int cpu_tmp; ++ ++ if (cpumask_test_cpu(best_cpu, tmpmask)) ++ goto out; ++ ++ for_each_cpu(cpu_tmp, tmpmask) { ++ int ranking, locality; ++ struct rq *tmp_rq; ++ ++ ranking = 0; ++ tmp_rq = cpu_rq(cpu_tmp); ++ ++ locality = rq->cpu_locality[cpu_tmp]; ++#ifdef CONFIG_NUMA ++ if (locality > 3) ++ ranking |= CPUIDLE_DIFF_NODE; ++ else ++#endif ++ if (locality > 2) ++ ranking |= CPUIDLE_DIFF_CPU; ++#ifdef CONFIG_SCHED_MC ++ else if (locality == 2) ++ ranking |= CPUIDLE_DIFF_CORE; ++ else if (!(tmp_rq->cache_idle(tmp_rq))) ++ ranking |= CPUIDLE_CACHE_BUSY; ++#endif ++#ifdef CONFIG_SCHED_SMT ++ if (locality == 1) ++ ranking |= CPUIDLE_DIFF_THREAD; ++ if (!(tmp_rq->siblings_idle(tmp_rq))) ++ ranking |= CPUIDLE_THREAD_BUSY; ++#endif ++ if (ranking < best_ranking) { ++ best_cpu = cpu_tmp; ++ best_ranking = ranking; ++ } ++ } ++out: ++ return best_cpu; ++} ++ ++bool cpus_share_cache(int this_cpu, int that_cpu) ++{ ++ struct rq *this_rq = cpu_rq(this_cpu); ++ ++ return (this_rq->cpu_locality[that_cpu] < 3); ++} ++ ++/* As per resched_curr but only will resched idle task */ ++static inline void resched_idle(struct rq *rq) ++{ ++ if (test_tsk_need_resched(rq->idle)) ++ return; ++ ++ rq->preempt = rq->idle; ++ ++ set_tsk_need_resched(rq->idle); ++ ++ if (rq_local(rq)) { ++ set_preempt_need_resched(); ++ return; ++ } ++ ++ smp_sched_reschedule(rq->cpu); ++} ++ ++static struct rq *resched_best_idle(struct task_struct *p, int cpu) ++{ ++ cpumask_t tmpmask; ++ struct rq *rq; ++ int best_cpu; ++ ++ cpumask_and(&tmpmask, &p->cpus_allowed, &cpu_idle_map); ++ best_cpu = best_mask_cpu(cpu, task_rq(p), &tmpmask); ++ rq = cpu_rq(best_cpu); ++ if (!smt_schedule(p, rq)) ++ return NULL; ++ rq->preempt = p; ++ resched_idle(rq); ++ return rq; ++} ++ ++static inline void resched_suitable_idle(struct task_struct *p) ++{ ++ if (suitable_idle_cpus(p)) ++ resched_best_idle(p, task_cpu(p)); ++} ++ ++static inline struct rq *rq_order(struct rq *rq, int cpu) ++{ ++ return rq->rq_order[cpu]; ++} ++#else /* CONFIG_SMP */ ++static inline void set_cpuidle_map(int cpu) ++{ ++} ++ ++static inline void clear_cpuidle_map(int cpu) ++{ ++} ++ ++static inline bool suitable_idle_cpus(struct task_struct *p) ++{ ++ return uprq->curr == uprq->idle; ++} ++ ++static inline void resched_suitable_idle(struct task_struct *p) ++{ ++} ++ ++static inline void resched_curr(struct rq *rq) ++{ ++ resched_task(rq->curr); ++} ++ ++static inline void resched_if_idle(struct rq *rq) ++{ ++} ++ ++static inline bool rq_local(struct rq *rq) ++{ ++ return true; ++} ++ ++static inline struct rq *rq_order(struct rq *rq, int cpu) ++{ ++ return rq; ++} ++ ++static inline bool smt_schedule(struct task_struct *p, struct rq *rq) ++{ ++ return true; ++} ++#endif /* CONFIG_SMP */ ++ ++static inline int normal_prio(struct task_struct *p) ++{ ++ if (has_rt_policy(p)) ++ return MAX_RT_PRIO - 1 - p->rt_priority; ++ if (idleprio_task(p)) ++ return IDLE_PRIO; ++ if (iso_task(p)) ++ return ISO_PRIO; ++ return NORMAL_PRIO; ++} ++ ++/* ++ * Calculate the current priority, i.e. the priority ++ * taken into account by the scheduler. This value might ++ * be boosted by RT tasks as it will be RT if the task got ++ * RT-boosted. If not then it returns p->normal_prio. ++ */ ++static int effective_prio(struct task_struct *p) ++{ ++ p->normal_prio = normal_prio(p); ++ /* ++ * If we are RT tasks or we were boosted to RT priority, ++ * keep the priority unchanged. Otherwise, update priority ++ * to the normal priority: ++ */ ++ if (!rt_prio(p->prio)) ++ return p->normal_prio; ++ return p->prio; ++} ++ ++/* ++ * activate_task - move a task to the runqueue. Enter with rq locked. ++ */ ++static void activate_task(struct task_struct *p, struct rq *rq) ++{ ++ resched_if_idle(rq); ++ ++ /* ++ * Sleep time is in units of nanosecs, so shift by 20 to get a ++ * milliseconds-range estimation of the amount of time that the task ++ * spent sleeping: ++ */ ++ if (unlikely(prof_on == SLEEP_PROFILING)) { ++ if (p->state == TASK_UNINTERRUPTIBLE) ++ profile_hits(SLEEP_PROFILING, (void *)get_wchan(p), ++ (rq->niffies - p->last_ran) >> 20); ++ } ++ ++ p->prio = effective_prio(p); ++ if (task_contributes_to_load(p)) ++ rq->nr_uninterruptible--; ++ ++ enqueue_task(rq, p, 0); ++ p->on_rq = TASK_ON_RQ_QUEUED; ++} ++ ++/* ++ * deactivate_task - If it's running, it's not on the runqueue and we can just ++ * decrement the nr_running. Enter with rq locked. ++ */ ++static inline void deactivate_task(struct task_struct *p, struct rq *rq) ++{ ++ if (task_contributes_to_load(p)) ++ rq->nr_uninterruptible++; ++ ++ p->on_rq = 0; ++ sched_info_dequeued(rq, p); ++} ++ ++#ifdef CONFIG_SMP ++void set_task_cpu(struct task_struct *p, unsigned int new_cpu) ++{ ++ struct rq *rq; ++ ++ if (task_cpu(p) == new_cpu) ++ return; ++ ++ /* Do NOT call set_task_cpu on a currently queued task as we will not ++ * be reliably holding the rq lock after changing CPU. */ ++ BUG_ON(task_queued(p)); ++ rq = task_rq(p); ++ ++#ifdef CONFIG_LOCKDEP ++ /* ++ * The caller should hold either p->pi_lock or rq->lock, when changing ++ * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks. ++ * ++ * Furthermore, all task_rq users should acquire both locks, see ++ * task_rq_lock(). ++ */ ++ WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || ++ lockdep_is_held(rq->lock))); ++#endif ++ ++ trace_sched_migrate_task(p, new_cpu); ++ rseq_migrate(p); ++ perf_event_task_migrate(p); ++ ++ /* ++ * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be ++ * successfully executed on another CPU. We must ensure that updates of ++ * per-task data have been completed by this moment. ++ */ ++ smp_wmb(); ++ ++ p->wake_cpu = new_cpu; ++ ++ if (task_running(rq, p)) { ++ /* ++ * We should only be calling this on a running task if we're ++ * holding rq lock. ++ */ ++ lockdep_assert_held(rq->lock); ++ ++ /* ++ * We can't change the task_thread_info CPU on a running task ++ * as p will still be protected by the rq lock of the CPU it ++ * is still running on so we only set the wake_cpu for it to be ++ * lazily updated once off the CPU. ++ */ ++ return; ++ } ++ ++#ifdef CONFIG_THREAD_INFO_IN_TASK ++ p->cpu = new_cpu; ++#else ++ task_thread_info(p)->cpu = new_cpu; ++#endif ++ /* We're no longer protecting p after this point since we're holding ++ * the wrong runqueue lock. */ ++} ++#endif /* CONFIG_SMP */ ++ ++/* ++ * Move a task off the runqueue and take it to a cpu for it will ++ * become the running task. ++ */ ++static inline void take_task(struct rq *rq, int cpu, struct task_struct *p) ++{ ++ struct rq *p_rq = task_rq(p); ++ ++ dequeue_task(p_rq, p, DEQUEUE_SAVE); ++ if (p_rq != rq) { ++ sched_info_dequeued(p_rq, p); ++ sched_info_queued(rq, p); ++ } ++ set_task_cpu(p, cpu); ++} ++ ++/* ++ * Returns a descheduling task to the runqueue unless it is being ++ * deactivated. ++ */ ++static inline void return_task(struct task_struct *p, struct rq *rq, ++ int cpu, bool deactivate) ++{ ++ if (deactivate) ++ deactivate_task(p, rq); ++ else { ++#ifdef CONFIG_SMP ++ /* ++ * set_task_cpu was called on the running task that doesn't ++ * want to deactivate so it has to be enqueued to a different ++ * CPU and we need its lock. Tag it to be moved with as the ++ * lock is dropped in finish_lock_switch. ++ */ ++ if (unlikely(p->wake_cpu != cpu)) ++ p->on_rq = TASK_ON_RQ_MIGRATING; ++ else ++#endif ++ enqueue_task(rq, p, ENQUEUE_RESTORE); ++ } ++} ++ ++/* Enter with rq lock held. We know p is on the local cpu */ ++static inline void __set_tsk_resched(struct task_struct *p) ++{ ++ set_tsk_need_resched(p); ++ set_preempt_need_resched(); ++} ++ ++/** ++ * task_curr - is this task currently executing on a CPU? ++ * @p: the task in question. ++ * ++ * Return: 1 if the task is currently executing. 0 otherwise. ++ */ ++inline int task_curr(const struct task_struct *p) ++{ ++ return cpu_curr(task_cpu(p)) == p; ++} ++ ++#ifdef CONFIG_SMP ++/* ++ * wait_task_inactive - wait for a thread to unschedule. ++ * ++ * If @match_state is nonzero, it's the @p->state value just checked and ++ * not expected to change. If it changes, i.e. @p might have woken up, ++ * then return zero. When we succeed in waiting for @p to be off its CPU, ++ * we return a positive number (its total switch count). If a second call ++ * a short while later returns the same number, the caller can be sure that ++ * @p has remained unscheduled the whole time. ++ * ++ * The caller must ensure that the task *will* unschedule sometime soon, ++ * else this function might spin for a *long* time. This function can't ++ * be called with interrupts off, or it may introduce deadlock with ++ * smp_call_function() if an IPI is sent by the same process we are ++ * waiting to become inactive. ++ */ ++unsigned long wait_task_inactive(struct task_struct *p, long match_state) ++{ ++ int running, queued; ++ unsigned long flags; ++ unsigned long ncsw; ++ struct rq *rq; ++ ++ for (;;) { ++ rq = task_rq(p); ++ ++ /* ++ * If the task is actively running on another CPU ++ * still, just relax and busy-wait without holding ++ * any locks. ++ * ++ * NOTE! Since we don't hold any locks, it's not ++ * even sure that "rq" stays as the right runqueue! ++ * But we don't care, since this will return false ++ * if the runqueue has changed and p is actually now ++ * running somewhere else! ++ */ ++ while (task_running(rq, p)) { ++ if (match_state && unlikely(p->state != match_state)) ++ return 0; ++ cpu_relax(); ++ } ++ ++ /* ++ * Ok, time to look more closely! We need the rq ++ * lock now, to be *sure*. If we're wrong, we'll ++ * just go back and repeat. ++ */ ++ rq = task_rq_lock(p, &flags); ++ trace_sched_wait_task(p); ++ running = task_running(rq, p); ++ queued = task_on_rq_queued(p); ++ ncsw = 0; ++ if (!match_state || p->state == match_state) ++ ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ ++ task_rq_unlock(rq, p, &flags); ++ ++ /* ++ * If it changed from the expected state, bail out now. ++ */ ++ if (unlikely(!ncsw)) ++ break; ++ ++ /* ++ * Was it really running after all now that we ++ * checked with the proper locks actually held? ++ * ++ * Oops. Go back and try again.. ++ */ ++ if (unlikely(running)) { ++ cpu_relax(); ++ continue; ++ } ++ ++ /* ++ * It's not enough that it's not actively running, ++ * it must be off the runqueue _entirely_, and not ++ * preempted! ++ * ++ * So if it was still runnable (but just not actively ++ * running right now), it's preempted, and we should ++ * yield - it could be a while. ++ */ ++ if (unlikely(queued)) { ++ ktime_t to = NSEC_PER_SEC / HZ; ++ ++ set_current_state(TASK_UNINTERRUPTIBLE); ++ schedule_hrtimeout(&to, HRTIMER_MODE_REL); ++ continue; ++ } ++ ++ /* ++ * Ahh, all good. It wasn't running, and it wasn't ++ * runnable, which means that it will never become ++ * running in the future either. We're all done! ++ */ ++ break; ++ } ++ ++ return ncsw; ++} ++ ++/*** ++ * kick_process - kick a running thread to enter/exit the kernel ++ * @p: the to-be-kicked thread ++ * ++ * Cause a process which is running on another CPU to enter ++ * kernel-mode, without any delay. (to get signals handled.) ++ * ++ * NOTE: this function doesn't have to take the runqueue lock, ++ * because all it wants to ensure is that the remote task enters ++ * the kernel. If the IPI races and the task has been migrated ++ * to another CPU then no harm is done and the purpose has been ++ * achieved as well. ++ */ ++void kick_process(struct task_struct *p) ++{ ++ int cpu; ++ ++ preempt_disable(); ++ cpu = task_cpu(p); ++ if ((cpu != smp_processor_id()) && task_curr(p)) ++ smp_sched_reschedule(cpu); ++ preempt_enable(); ++} ++EXPORT_SYMBOL_GPL(kick_process); ++#endif ++ ++/* ++ * RT tasks preempt purely on priority. SCHED_NORMAL tasks preempt on the ++ * basis of earlier deadlines. SCHED_IDLEPRIO don't preempt anything else or ++ * between themselves, they cooperatively multitask. An idle rq scores as ++ * prio PRIO_LIMIT so it is always preempted. ++ */ ++static inline bool ++can_preempt(struct task_struct *p, int prio, u64 deadline) ++{ ++ /* Better static priority RT task or better policy preemption */ ++ if (p->prio < prio) ++ return true; ++ if (p->prio > prio) ++ return false; ++ if (p->policy == SCHED_BATCH) ++ return false; ++ /* SCHED_NORMAL and ISO will preempt based on deadline */ ++ if (!deadline_before(p->deadline, deadline)) ++ return false; ++ return true; ++} ++ ++#ifdef CONFIG_SMP ++ ++static inline bool is_per_cpu_kthread(struct task_struct *p) ++{ ++ if (!(p->flags & PF_KTHREAD)) ++ return false; ++ ++ if (p->nr_cpus_allowed != 1) ++ return false; ++ ++ return true; ++} ++ ++/* ++ * Per-CPU kthreads are allowed to run on !active && online CPUs, see ++ * __set_cpus_allowed_ptr(). ++ */ ++static inline bool is_cpu_allowed(struct task_struct *p, int cpu) ++{ ++ if (!cpumask_test_cpu(cpu, &p->cpus_allowed)) ++ return false; ++ ++ if (is_per_cpu_kthread(p)) ++ return cpu_online(cpu); ++ ++ return cpu_active(cpu); ++} ++ ++/* ++ * Check to see if p can run on cpu, and if not, whether there are any online ++ * CPUs it can run on instead. This only happens with the hotplug threads that ++ * bring up the CPUs. ++ */ ++static inline bool sched_other_cpu(struct task_struct *p, int cpu) ++{ ++ if (likely(cpumask_test_cpu(cpu, &p->cpus_allowed))) ++ return false; ++ if (p->nr_cpus_allowed == 1) { ++ cpumask_t valid_mask; ++ ++ cpumask_and(&valid_mask, &p->cpus_allowed, cpu_online_mask); ++ if (unlikely(cpumask_empty(&valid_mask))) ++ return false; ++ } ++ return true; ++} ++ ++static inline bool needs_other_cpu(struct task_struct *p, int cpu) ++{ ++ if (cpumask_test_cpu(cpu, &p->cpus_allowed)) ++ return false; ++ return true; ++} ++ ++#define cpu_online_map (*(cpumask_t *)cpu_online_mask) ++ ++static void try_preempt(struct task_struct *p, struct rq *this_rq) ++{ ++ int i, this_entries = rq_load(this_rq); ++ cpumask_t tmp; ++ ++ if (suitable_idle_cpus(p) && resched_best_idle(p, task_cpu(p))) ++ return; ++ ++ /* IDLEPRIO tasks never preempt anything but idle */ ++ if (p->policy == SCHED_IDLEPRIO) ++ return; ++ ++ cpumask_and(&tmp, &cpu_online_map, &p->cpus_allowed); ++ ++ for (i = 0; i < num_possible_cpus(); i++) { ++ struct rq *rq = this_rq->cpu_order[i]; ++ ++ if (!cpumask_test_cpu(rq->cpu, &tmp)) ++ continue; ++ ++ if (!sched_interactive && rq != this_rq && rq_load(rq) <= this_entries) ++ continue; ++ if (smt_schedule(p, rq) && can_preempt(p, rq->rq_prio, rq->rq_deadline)) { ++ /* We set rq->preempting lockless, it's a hint only */ ++ rq->preempting = p; ++ resched_curr(rq); ++ return; ++ } ++ } ++} ++ ++static int __set_cpus_allowed_ptr(struct task_struct *p, ++ const struct cpumask *new_mask, bool check); ++#else /* CONFIG_SMP */ ++static inline bool needs_other_cpu(struct task_struct *p, int cpu) ++{ ++ return false; ++} ++ ++static void try_preempt(struct task_struct *p, struct rq *this_rq) ++{ ++ if (p->policy == SCHED_IDLEPRIO) ++ return; ++ if (can_preempt(p, uprq->rq_prio, uprq->rq_deadline)) ++ resched_curr(uprq); ++} ++ ++static inline int __set_cpus_allowed_ptr(struct task_struct *p, ++ const struct cpumask *new_mask, bool check) ++{ ++ return set_cpus_allowed_ptr(p, new_mask); ++} ++#endif /* CONFIG_SMP */ ++ ++/* ++ * wake flags ++ */ ++#define WF_SYNC 0x01 /* waker goes to sleep after wakeup */ ++#define WF_FORK 0x02 /* child wakeup after fork */ ++#define WF_MIGRATED 0x04 /* internal use, task got migrated */ ++ ++static void ++ttwu_stat(struct task_struct *p, int cpu, int wake_flags) ++{ ++ struct rq *rq; ++ ++ if (!schedstat_enabled()) ++ return; ++ ++ rq = this_rq(); ++ ++#ifdef CONFIG_SMP ++ if (cpu == rq->cpu) { ++ __schedstat_inc(rq->ttwu_local); ++ } else { ++ struct sched_domain *sd; ++ ++ rcu_read_lock(); ++ for_each_domain(rq->cpu, sd) { ++ if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { ++ __schedstat_inc(sd->ttwu_wake_remote); ++ break; ++ } ++ } ++ rcu_read_unlock(); ++ } ++ ++#endif /* CONFIG_SMP */ ++ ++ __schedstat_inc(rq->ttwu_count); ++} ++ ++static inline void ttwu_activate(struct rq *rq, struct task_struct *p) ++{ ++ activate_task(p, rq); ++ ++ /* if a worker is waking up, notify the workqueue */ ++ if (p->flags & PF_WQ_WORKER) ++ wq_worker_waking_up(p, cpu_of(rq)); ++} ++ ++/* ++ * Mark the task runnable and perform wakeup-preemption. ++ */ ++static void ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) ++{ ++ /* ++ * Sync wakeups (i.e. those types of wakeups where the waker ++ * has indicated that it will leave the CPU in short order) ++ * don't trigger a preemption if there are no idle cpus, ++ * instead waiting for current to deschedule. ++ */ ++ if (wake_flags & WF_SYNC) ++ resched_suitable_idle(p); ++ else ++ try_preempt(p, rq); ++ p->state = TASK_RUNNING; ++ trace_sched_wakeup(p); ++} ++ ++static void ++ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags) ++{ ++ lockdep_assert_held(rq->lock); ++ ++#ifdef CONFIG_SMP ++ if (p->sched_contributes_to_load) ++ rq->nr_uninterruptible--; ++#endif ++ ++ ttwu_activate(rq, p); ++ ttwu_do_wakeup(rq, p, wake_flags); ++} ++ ++/* ++ * Called in case the task @p isn't fully descheduled from its runqueue, ++ * in this case we must do a remote wakeup. Its a 'light' wakeup though, ++ * since all we need to do is flip p->state to TASK_RUNNING, since ++ * the task is still ->on_rq. ++ */ ++static int ttwu_remote(struct task_struct *p, int wake_flags) ++{ ++ struct rq *rq; ++ int ret = 0; ++ ++ rq = __task_rq_lock(p); ++ if (likely(task_on_rq_queued(p))) { ++ ttwu_do_wakeup(rq, p, wake_flags); ++ ret = 1; ++ } ++ __task_rq_unlock(rq); ++ ++ return ret; ++} ++ ++#ifdef CONFIG_SMP ++void sched_ttwu_pending(void) ++{ ++ struct rq *rq = this_rq(); ++ struct llist_node *llist = llist_del_all(&rq->wake_list); ++ struct task_struct *p, *t; ++ unsigned long flags; ++ ++ if (!llist) ++ return; ++ ++ rq_lock_irqsave(rq, &flags); ++ ++ llist_for_each_entry_safe(p, t, llist, wake_entry) ++ ttwu_do_activate(rq, p, 0); ++ ++ rq_unlock_irqrestore(rq, &flags); ++} ++ ++void scheduler_ipi(void) ++{ ++ /* ++ * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting ++ * TIF_NEED_RESCHED remotely (for the first time) will also send ++ * this IPI. ++ */ ++ preempt_fold_need_resched(); ++ ++ if (llist_empty(&this_rq()->wake_list) && (!idle_cpu(smp_processor_id()) || need_resched())) ++ return; ++ ++ /* ++ * Not all reschedule IPI handlers call irq_enter/irq_exit, since ++ * traditionally all their work was done from the interrupt return ++ * path. Now that we actually do some work, we need to make sure ++ * we do call them. ++ * ++ * Some archs already do call them, luckily irq_enter/exit nest ++ * properly. ++ * ++ * Arguably we should visit all archs and update all handlers, ++ * however a fair share of IPIs are still resched only so this would ++ * somewhat pessimize the simple resched case. ++ */ ++ irq_enter(); ++ sched_ttwu_pending(); ++ irq_exit(); ++} ++ ++static void ttwu_queue_remote(struct task_struct *p, int cpu, int wake_flags) ++{ ++ struct rq *rq = cpu_rq(cpu); ++ ++ if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) { ++ if (!set_nr_if_polling(rq->idle)) ++ smp_sched_reschedule(cpu); ++ else ++ trace_sched_wake_idle_without_ipi(cpu); ++ } ++} ++ ++void wake_up_if_idle(int cpu) ++{ ++ struct rq *rq = cpu_rq(cpu); ++ unsigned long flags; ++ ++ rcu_read_lock(); ++ ++ if (!is_idle_task(rcu_dereference(rq->curr))) ++ goto out; ++ ++ if (set_nr_if_polling(rq->idle)) { ++ trace_sched_wake_idle_without_ipi(cpu); ++ } else { ++ rq_lock_irqsave(rq, &flags); ++ if (likely(is_idle_task(rq->curr))) ++ smp_sched_reschedule(cpu); ++ /* Else cpu is not in idle, do nothing here */ ++ rq_unlock_irqrestore(rq, &flags); ++ } ++ ++out: ++ rcu_read_unlock(); ++} ++ ++static int valid_task_cpu(struct task_struct *p) ++{ ++ cpumask_t valid_mask; ++ ++ if (p->flags & PF_KTHREAD) ++ cpumask_and(&valid_mask, &p->cpus_allowed, cpu_all_mask); ++ else ++ cpumask_and(&valid_mask, &p->cpus_allowed, cpu_active_mask); ++ ++ if (unlikely(!cpumask_weight(&valid_mask))) { ++ /* We shouldn't be hitting this any more */ ++ printk(KERN_WARNING "SCHED: No cpumask for %s/%d weight %d\n", p->comm, ++ p->pid, cpumask_weight(&p->cpus_allowed)); ++ return cpumask_any(&p->cpus_allowed); ++ } ++ return cpumask_any(&valid_mask); ++} ++ ++/* ++ * For a task that's just being woken up we have a valuable balancing ++ * opportunity so choose the nearest cache most lightly loaded runqueue. ++ * Entered with rq locked and returns with the chosen runqueue locked. ++ */ ++static inline int select_best_cpu(struct task_struct *p) ++{ ++ unsigned int idlest = ~0U; ++ struct rq *rq = NULL; ++ int i; ++ ++ if (suitable_idle_cpus(p)) { ++ int cpu = task_cpu(p); ++ ++ if (unlikely(needs_other_cpu(p, cpu))) ++ cpu = valid_task_cpu(p); ++ rq = resched_best_idle(p, cpu); ++ if (likely(rq)) ++ return rq->cpu; ++ } ++ ++ for (i = 0; i < num_possible_cpus(); i++) { ++ struct rq *other_rq = task_rq(p)->cpu_order[i]; ++ int entries; ++ ++ if (!other_rq->online) ++ continue; ++ if (needs_other_cpu(p, other_rq->cpu)) ++ continue; ++ entries = rq_load(other_rq); ++ if (entries >= idlest) ++ continue; ++ idlest = entries; ++ rq = other_rq; ++ } ++ if (unlikely(!rq)) ++ return task_cpu(p); ++ return rq->cpu; ++} ++#else /* CONFIG_SMP */ ++static int valid_task_cpu(struct task_struct *p) ++{ ++ return 0; ++} ++ ++static inline int select_best_cpu(struct task_struct *p) ++{ ++ return 0; ++} ++ ++static struct rq *resched_best_idle(struct task_struct *p, int cpu) ++{ ++ return NULL; ++} ++#endif /* CONFIG_SMP */ ++ ++static void ttwu_queue(struct task_struct *p, int cpu, int wake_flags) ++{ ++ struct rq *rq = cpu_rq(cpu); ++ ++#if defined(CONFIG_SMP) ++ if (!cpus_share_cache(smp_processor_id(), cpu)) { ++ sched_clock_cpu(cpu); /* Sync clocks across CPUs */ ++ ttwu_queue_remote(p, cpu, wake_flags); ++ return; ++ } ++#endif ++ rq_lock(rq); ++ ttwu_do_activate(rq, p, wake_flags); ++ rq_unlock(rq); ++} ++ ++/*** ++ * try_to_wake_up - wake up a thread ++ * @p: the thread to be awakened ++ * @state: the mask of task states that can be woken ++ * @wake_flags: wake modifier flags (WF_*) ++ * ++ * Put it on the run-queue if it's not already there. The "current" ++ * thread is always on the run-queue (except when the actual ++ * re-schedule is in progress), and as such you're allowed to do ++ * the simpler "current->state = TASK_RUNNING" to mark yourself ++ * runnable without the overhead of this. ++ * ++ * Return: %true if @p was woken up, %false if it was already running. ++ * or @state didn't match @p's state. ++ */ ++static int ++try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) ++{ ++ unsigned long flags; ++ int cpu, success = 0; ++ ++ /* ++ * If we are going to wake up a thread waiting for CONDITION we ++ * need to ensure that CONDITION=1 done by the caller can not be ++ * reordered with p->state check below. This pairs with mb() in ++ * set_current_state() the waiting thread does. ++ */ ++ raw_spin_lock_irqsave(&p->pi_lock, flags); ++ smp_mb__after_spinlock(); ++ /* state is a volatile long, どうして、分からない */ ++ if (!((unsigned int)p->state & state)) ++ goto out; ++ ++ trace_sched_waking(p); ++ ++ /* We're going to change ->state: */ ++ success = 1; ++ cpu = task_cpu(p); ++ ++ /* ++ * Ensure we load p->on_rq _after_ p->state, otherwise it would ++ * be possible to, falsely, observe p->on_rq == 0 and get stuck ++ * in smp_cond_load_acquire() below. ++ * ++ * sched_ttwu_pending() try_to_wake_up() ++ * STORE p->on_rq = 1 LOAD p->state ++ * UNLOCK rq->lock ++ * ++ * __schedule() (switch to task 'p') ++ * LOCK rq->lock smp_rmb(); ++ * smp_mb__after_spinlock(); ++ * UNLOCK rq->lock ++ * ++ * [task p] ++ * STORE p->state = UNINTERRUPTIBLE LOAD p->on_rq ++ * ++ * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in ++ * __schedule(). See the comment for smp_mb__after_spinlock(). ++ */ ++ smp_rmb(); ++ if (p->on_rq && ttwu_remote(p, wake_flags)) ++ goto stat; ++ ++#ifdef CONFIG_SMP ++ /* ++ * Ensure we load p->on_cpu _after_ p->on_rq, otherwise it would be ++ * possible to, falsely, observe p->on_cpu == 0. ++ * ++ * One must be running (->on_cpu == 1) in order to remove oneself ++ * from the runqueue. ++ * ++ * __schedule() (switch to task 'p') try_to_wake_up() ++ * STORE p->on_cpu = 1 LOAD p->on_rq ++ * UNLOCK rq->lock ++ * ++ * __schedule() (put 'p' to sleep) ++ * LOCK rq->lock smp_rmb(); ++ * smp_mb__after_spinlock(); ++ * STORE p->on_rq = 0 LOAD p->on_cpu ++ * ++ * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in ++ * __schedule(). See the comment for smp_mb__after_spinlock(). ++ */ ++ smp_rmb(); ++ ++ /* ++ * If the owning (remote) CPU is still in the middle of schedule() with ++ * this task as prev, wait until its done referencing the task. ++ * ++ * Pairs with the smp_store_release() in finish_task(). ++ * ++ * This ensures that tasks getting woken will be fully ordered against ++ * their previous state and preserve Program Order. ++ */ ++ smp_cond_load_acquire(&p->on_cpu, !VAL); ++ ++ p->sched_contributes_to_load = !!task_contributes_to_load(p); ++ p->state = TASK_WAKING; ++ ++ if (p->in_iowait) { ++ delayacct_blkio_end(p); ++ atomic_dec(&task_rq(p)->nr_iowait); ++ } ++ ++ cpu = select_best_cpu(p); ++ if (task_cpu(p) != cpu) ++ set_task_cpu(p, cpu); ++ ++#else /* CONFIG_SMP */ ++ ++ if (p->in_iowait) { ++ delayacct_blkio_end(p); ++ atomic_dec(&task_rq(p)->nr_iowait); ++ } ++ ++#endif /* CONFIG_SMP */ ++ ++ ttwu_queue(p, cpu, wake_flags); ++stat: ++ ttwu_stat(p, cpu, wake_flags); ++out: ++ raw_spin_unlock_irqrestore(&p->pi_lock, flags); ++ ++ return success; ++} ++ ++/** ++ * try_to_wake_up_local - try to wake up a local task with rq lock held ++ * @p: the thread to be awakened ++ * ++ * Put @p on the run-queue if it's not already there. The caller must ++ * ensure that rq is locked and, @p is not the current task. ++ * rq stays locked over invocation. ++ */ ++static void try_to_wake_up_local(struct task_struct *p) ++{ ++ struct rq *rq = task_rq(p); ++ ++ if (WARN_ON_ONCE(rq != this_rq()) || ++ WARN_ON_ONCE(p == current)) ++ return; ++ ++ lockdep_assert_held(rq->lock); ++ ++ if (!raw_spin_trylock(&p->pi_lock)) { ++ /* ++ * This is OK, because current is on_cpu, which avoids it being ++ * picked for load-balance and preemption/IRQs are still ++ * disabled avoiding further scheduler activity on it and we've ++ * not yet picked a replacement task. ++ */ ++ rq_unlock(rq); ++ raw_spin_lock(&p->pi_lock); ++ rq_lock(rq); ++ } ++ ++ if (!(p->state & TASK_NORMAL)) ++ goto out; ++ ++ trace_sched_waking(p); ++ ++ if (!task_on_rq_queued(p)) { ++ if (p->in_iowait) { ++ delayacct_blkio_end(p); ++ atomic_dec(&rq->nr_iowait); ++ } ++ ttwu_activate(rq, p); ++ } ++ ++ ttwu_do_wakeup(rq, p, 0); ++ ttwu_stat(p, smp_processor_id(), 0); ++out: ++ raw_spin_unlock(&p->pi_lock); ++} ++ ++/** ++ * wake_up_process - Wake up a specific process ++ * @p: The process to be woken up. ++ * ++ * Attempt to wake up the nominated process and move it to the set of runnable ++ * processes. ++ * ++ * Return: 1 if the process was woken up, 0 if it was already running. ++ * ++ * This function executes a full memory barrier before accessing the task state. ++ */ ++int wake_up_process(struct task_struct *p) ++{ ++ return try_to_wake_up(p, TASK_NORMAL, 0); ++} ++EXPORT_SYMBOL(wake_up_process); ++ ++int wake_up_state(struct task_struct *p, unsigned int state) ++{ ++ return try_to_wake_up(p, state, 0); ++} ++ ++static void time_slice_expired(struct task_struct *p, struct rq *rq); ++ ++/* ++ * Perform scheduler related setup for a newly forked process p. ++ * p is forked by current. ++ */ ++int sched_fork(unsigned long __maybe_unused clone_flags, struct task_struct *p) ++{ ++ unsigned long flags; ++ ++#ifdef CONFIG_PREEMPT_NOTIFIERS ++ INIT_HLIST_HEAD(&p->preempt_notifiers); ++#endif ++ /* ++ * We mark the process as NEW here. This guarantees that ++ * nobody will actually run it, and a signal or other external ++ * event cannot wake it up and insert it on the runqueue either. ++ */ ++ p->state = TASK_NEW; ++ ++ /* ++ * The process state is set to the same value of the process executing ++ * do_fork() code. That is running. This guarantees that nobody will ++ * actually run it, and a signal or other external event cannot wake ++ * it up and insert it on the runqueue either. ++ */ ++ ++ /* Should be reset in fork.c but done here for ease of MuQSS patching */ ++ p->on_cpu = ++ p->on_rq = ++ p->utime = ++ p->stime = ++ p->sched_time = ++ p->stime_ns = ++ p->utime_ns = 0; ++ skiplist_node_init(&p->node); ++ ++ /* ++ * Revert to default priority/policy on fork if requested. ++ */ ++ if (unlikely(p->sched_reset_on_fork)) { ++ if (p->policy == SCHED_FIFO || p->policy == SCHED_RR) { ++ p->policy = SCHED_NORMAL; ++ p->normal_prio = normal_prio(p); ++ } ++ ++ if (PRIO_TO_NICE(p->static_prio) < 0) { ++ p->static_prio = NICE_TO_PRIO(0); ++ p->normal_prio = p->static_prio; ++ } ++ ++ /* ++ * We don't need the reset flag anymore after the fork. It has ++ * fulfilled its duty: ++ */ ++ p->sched_reset_on_fork = 0; ++ } ++ ++ /* ++ * Silence PROVE_RCU. ++ */ ++ raw_spin_lock_irqsave(&p->pi_lock, flags); ++ set_task_cpu(p, smp_processor_id()); ++ raw_spin_unlock_irqrestore(&p->pi_lock, flags); ++ ++#ifdef CONFIG_SCHED_INFO ++ if (unlikely(sched_info_on())) ++ memset(&p->sched_info, 0, sizeof(p->sched_info)); ++#endif ++ init_task_preempt_count(p); ++ ++ return 0; ++} ++ ++#ifdef CONFIG_SCHEDSTATS ++ ++DEFINE_STATIC_KEY_FALSE(sched_schedstats); ++static bool __initdata __sched_schedstats = false; ++ ++static void set_schedstats(bool enabled) ++{ ++ if (enabled) ++ static_branch_enable(&sched_schedstats); ++ else ++ static_branch_disable(&sched_schedstats); ++} ++ ++void force_schedstat_enabled(void) ++{ ++ if (!schedstat_enabled()) { ++ pr_info("kernel profiling enabled schedstats, disable via kernel.sched_schedstats.\n"); ++ static_branch_enable(&sched_schedstats); ++ } ++} ++ ++static int __init setup_schedstats(char *str) ++{ ++ int ret = 0; ++ if (!str) ++ goto out; ++ ++ /* ++ * This code is called before jump labels have been set up, so we can't ++ * change the static branch directly just yet. Instead set a temporary ++ * variable so init_schedstats() can do it later. ++ */ ++ if (!strcmp(str, "enable")) { ++ __sched_schedstats = true; ++ ret = 1; ++ } else if (!strcmp(str, "disable")) { ++ __sched_schedstats = false; ++ ret = 1; ++ } ++out: ++ if (!ret) ++ pr_warn("Unable to parse schedstats=\n"); ++ ++ return ret; ++} ++__setup("schedstats=", setup_schedstats); ++ ++static void __init init_schedstats(void) ++{ ++ set_schedstats(__sched_schedstats); ++} ++ ++#ifdef CONFIG_PROC_SYSCTL ++int sysctl_schedstats(struct ctl_table *table, int write, ++ void __user *buffer, size_t *lenp, loff_t *ppos) ++{ ++ struct ctl_table t; ++ int err; ++ int state = static_branch_likely(&sched_schedstats); ++ ++ if (write && !capable(CAP_SYS_ADMIN)) ++ return -EPERM; ++ ++ t = *table; ++ t.data = &state; ++ err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); ++ if (err < 0) ++ return err; ++ if (write) ++ set_schedstats(state); ++ return err; ++} ++#endif /* CONFIG_PROC_SYSCTL */ ++#else /* !CONFIG_SCHEDSTATS */ ++static inline void init_schedstats(void) {} ++#endif /* CONFIG_SCHEDSTATS */ ++ ++static void update_cpu_clock_switch(struct rq *rq, struct task_struct *p); ++ ++static void account_task_cpu(struct rq *rq, struct task_struct *p) ++{ ++ update_clocks(rq); ++ /* This isn't really a context switch but accounting is the same */ ++ update_cpu_clock_switch(rq, p); ++ p->last_ran = rq->niffies; ++} ++ ++bool sched_smp_initialized __read_mostly; ++ ++static inline int hrexpiry_enabled(struct rq *rq) ++{ ++ if (unlikely(!cpu_active(cpu_of(rq)) || !sched_smp_initialized)) ++ return 0; ++ return hrtimer_is_hres_active(&rq->hrexpiry_timer); ++} ++ ++/* ++ * Use HR-timers to deliver accurate preemption points. ++ */ ++static inline void hrexpiry_clear(struct rq *rq) ++{ ++ if (!hrexpiry_enabled(rq)) ++ return; ++ if (hrtimer_active(&rq->hrexpiry_timer)) ++ hrtimer_cancel(&rq->hrexpiry_timer); ++} ++ ++/* ++ * High-resolution time_slice expiry. ++ * Runs from hardirq context with interrupts disabled. ++ */ ++static enum hrtimer_restart hrexpiry(struct hrtimer *timer) ++{ ++ struct rq *rq = container_of(timer, struct rq, hrexpiry_timer); ++ struct task_struct *p; ++ ++ /* This can happen during CPU hotplug / resume */ ++ if (unlikely(cpu_of(rq) != smp_processor_id())) ++ goto out; ++ ++ /* ++ * We're doing this without the runqueue lock but this should always ++ * be run on the local CPU. Time slice should run out in __schedule ++ * but we set it to zero here in case niffies is slightly less. ++ */ ++ p = rq->curr; ++ p->time_slice = 0; ++ __set_tsk_resched(p); ++out: ++ return HRTIMER_NORESTART; ++} ++ ++/* ++ * Called to set the hrexpiry timer state. ++ * ++ * called with irqs disabled from the local CPU only ++ */ ++static void hrexpiry_start(struct rq *rq, u64 delay) ++{ ++ if (!hrexpiry_enabled(rq)) ++ return; ++ ++ hrtimer_start(&rq->hrexpiry_timer, ns_to_ktime(delay), ++ HRTIMER_MODE_REL_PINNED); ++} ++ ++static void init_rq_hrexpiry(struct rq *rq) ++{ ++ hrtimer_init(&rq->hrexpiry_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); ++ rq->hrexpiry_timer.function = hrexpiry; ++} ++ ++static inline int rq_dither(struct rq *rq) ++{ ++ if (!hrexpiry_enabled(rq)) ++ return HALF_JIFFY_US; ++ return 0; ++} ++ ++/* ++ * wake_up_new_task - wake up a newly created task for the first time. ++ * ++ * This function will do some initial scheduler statistics housekeeping ++ * that must be done for every newly created context, then puts the task ++ * on the runqueue and wakes it. ++ */ ++void wake_up_new_task(struct task_struct *p) ++{ ++ struct task_struct *parent, *rq_curr; ++ struct rq *rq, *new_rq; ++ unsigned long flags; ++ ++ parent = p->parent; ++ ++ raw_spin_lock_irqsave(&p->pi_lock, flags); ++ p->state = TASK_RUNNING; ++ /* Task_rq can't change yet on a new task */ ++ new_rq = rq = task_rq(p); ++ if (unlikely(needs_other_cpu(p, task_cpu(p)))) { ++ set_task_cpu(p, valid_task_cpu(p)); ++ new_rq = task_rq(p); ++ } ++ ++ double_rq_lock(rq, new_rq); ++ rq_curr = rq->curr; ++ ++ /* ++ * Make sure we do not leak PI boosting priority to the child. ++ */ ++ p->prio = rq_curr->normal_prio; ++ ++ trace_sched_wakeup_new(p); ++ ++ /* ++ * Share the timeslice between parent and child, thus the ++ * total amount of pending timeslices in the system doesn't change, ++ * resulting in more scheduling fairness. If it's negative, it won't ++ * matter since that's the same as being 0. rq->rq_deadline is only ++ * modified within schedule() so it is always equal to ++ * current->deadline. ++ */ ++ account_task_cpu(rq, rq_curr); ++ p->last_ran = rq_curr->last_ran; ++ if (likely(rq_curr->policy != SCHED_FIFO)) { ++ rq_curr->time_slice /= 2; ++ if (rq_curr->time_slice < RESCHED_US) { ++ /* ++ * Forking task has run out of timeslice. Reschedule it and ++ * start its child with a new time slice and deadline. The ++ * child will end up running first because its deadline will ++ * be slightly earlier. ++ */ ++ __set_tsk_resched(rq_curr); ++ time_slice_expired(p, new_rq); ++ if (suitable_idle_cpus(p)) ++ resched_best_idle(p, task_cpu(p)); ++ else if (unlikely(rq != new_rq)) ++ try_preempt(p, new_rq); ++ } else { ++ p->time_slice = rq_curr->time_slice; ++ if (rq_curr == parent && rq == new_rq && !suitable_idle_cpus(p)) { ++ /* ++ * The VM isn't cloned, so we're in a good position to ++ * do child-runs-first in anticipation of an exec. This ++ * usually avoids a lot of COW overhead. ++ */ ++ __set_tsk_resched(rq_curr); ++ } else { ++ /* ++ * Adjust the hrexpiry since rq_curr will keep ++ * running and its timeslice has been shortened. ++ */ ++ hrexpiry_start(rq, US_TO_NS(rq_curr->time_slice)); ++ try_preempt(p, new_rq); ++ } ++ } ++ } else { ++ time_slice_expired(p, new_rq); ++ try_preempt(p, new_rq); ++ } ++ activate_task(p, new_rq); ++ double_rq_unlock(rq, new_rq); ++ raw_spin_unlock_irqrestore(&p->pi_lock, flags); ++} ++ ++#ifdef CONFIG_PREEMPT_NOTIFIERS ++ ++static DEFINE_STATIC_KEY_FALSE(preempt_notifier_key); ++ ++void preempt_notifier_inc(void) ++{ ++ static_branch_inc(&preempt_notifier_key); ++} ++EXPORT_SYMBOL_GPL(preempt_notifier_inc); ++ ++void preempt_notifier_dec(void) ++{ ++ static_branch_dec(&preempt_notifier_key); ++} ++EXPORT_SYMBOL_GPL(preempt_notifier_dec); ++ ++/** ++ * preempt_notifier_register - tell me when current is being preempted & rescheduled ++ * @notifier: notifier struct to register ++ */ ++void preempt_notifier_register(struct preempt_notifier *notifier) ++{ ++ if (!static_branch_unlikely(&preempt_notifier_key)) ++ WARN(1, "registering preempt_notifier while notifiers disabled\n"); ++ ++ hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); ++} ++EXPORT_SYMBOL_GPL(preempt_notifier_register); ++ ++/** ++ * preempt_notifier_unregister - no longer interested in preemption notifications ++ * @notifier: notifier struct to unregister ++ * ++ * This is *not* safe to call from within a preemption notifier. ++ */ ++void preempt_notifier_unregister(struct preempt_notifier *notifier) ++{ ++ hlist_del(¬ifier->link); ++} ++EXPORT_SYMBOL_GPL(preempt_notifier_unregister); ++ ++static void __fire_sched_in_preempt_notifiers(struct task_struct *curr) ++{ ++ struct preempt_notifier *notifier; ++ ++ hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) ++ notifier->ops->sched_in(notifier, raw_smp_processor_id()); ++} ++ ++static __always_inline void fire_sched_in_preempt_notifiers(struct task_struct *curr) ++{ ++ if (static_branch_unlikely(&preempt_notifier_key)) ++ __fire_sched_in_preempt_notifiers(curr); ++} ++ ++static void ++__fire_sched_out_preempt_notifiers(struct task_struct *curr, ++ struct task_struct *next) ++{ ++ struct preempt_notifier *notifier; ++ ++ hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) ++ notifier->ops->sched_out(notifier, next); ++} ++ ++static __always_inline void ++fire_sched_out_preempt_notifiers(struct task_struct *curr, ++ struct task_struct *next) ++{ ++ if (static_branch_unlikely(&preempt_notifier_key)) ++ __fire_sched_out_preempt_notifiers(curr, next); ++} ++ ++#else /* !CONFIG_PREEMPT_NOTIFIERS */ ++ ++static inline void fire_sched_in_preempt_notifiers(struct task_struct *curr) ++{ ++} ++ ++static inline void ++fire_sched_out_preempt_notifiers(struct task_struct *curr, ++ struct task_struct *next) ++{ ++} ++ ++#endif /* CONFIG_PREEMPT_NOTIFIERS */ ++ ++static inline void prepare_task(struct task_struct *next) ++{ ++ /* ++ * Claim the task as running, we do this before switching to it ++ * such that any running task will have this set. ++ */ ++ next->on_cpu = 1; ++} ++ ++static inline void finish_task(struct task_struct *prev) ++{ ++#ifdef CONFIG_SMP ++ /* ++ * After ->on_cpu is cleared, the task can be moved to a different CPU. ++ * We must ensure this doesn't happen until the switch is completely ++ * finished. ++ * ++ * In particular, the load of prev->state in finish_task_switch() must ++ * happen before this. ++ * ++ * Pairs with the smp_cond_load_acquire() in try_to_wake_up(). ++ */ ++ smp_store_release(&prev->on_cpu, 0); ++#endif ++} ++ ++static inline void ++prepare_lock_switch(struct rq *rq, struct task_struct *next) ++{ ++ /* ++ * Since the runqueue lock will be released by the next ++ * task (which is an invalid locking op but in the case ++ * of the scheduler it's an obvious special-case), so we ++ * do an early lockdep release here: ++ */ ++ spin_release(&rq->lock.dep_map, 1, _THIS_IP_); ++#ifdef CONFIG_DEBUG_SPINLOCK ++ /* this is a valid case when another task releases the spinlock */ ++ rq->lock.owner = next; ++#endif ++} ++ ++static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) ++{ ++ /* ++ * If we are tracking spinlock dependencies then we have to ++ * fix up the runqueue lock - which gets 'carried over' from ++ * prev into current: ++ */ ++ spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_); ++ ++#ifdef CONFIG_SMP ++ /* ++ * If prev was marked as migrating to another CPU in return_task, drop ++ * the local runqueue lock but leave interrupts disabled and grab the ++ * remote lock we're migrating it to before enabling them. ++ */ ++ if (unlikely(task_on_rq_migrating(prev))) { ++ sched_info_dequeued(rq, prev); ++ /* ++ * We move the ownership of prev to the new cpu now. ttwu can't ++ * activate prev to the wrong cpu since it has to grab this ++ * runqueue in ttwu_remote. ++ */ ++#ifdef CONFIG_THREAD_INFO_IN_TASK ++ prev->cpu = prev->wake_cpu; ++#else ++ task_thread_info(prev)->cpu = prev->wake_cpu; ++#endif ++ raw_spin_unlock(rq->lock); ++ ++ raw_spin_lock(&prev->pi_lock); ++ rq = __task_rq_lock(prev); ++ /* Check that someone else hasn't already queued prev */ ++ if (likely(!task_queued(prev))) { ++ enqueue_task(rq, prev, 0); ++ prev->on_rq = TASK_ON_RQ_QUEUED; ++ /* Wake up the CPU if it's not already running */ ++ resched_if_idle(rq); ++ } ++ raw_spin_unlock(&prev->pi_lock); ++ } ++#endif ++ rq_unlock(rq); ++ ++ do_pending_softirq(rq, current); ++ ++ local_irq_enable(); ++} ++ ++#ifndef prepare_arch_switch ++# define prepare_arch_switch(next) do { } while (0) ++#endif ++#ifndef finish_arch_switch ++# define finish_arch_switch(prev) do { } while (0) ++#endif ++#ifndef finish_arch_post_lock_switch ++# define finish_arch_post_lock_switch() do { } while (0) ++#endif ++ ++/** ++ * prepare_task_switch - prepare to switch tasks ++ * @rq: the runqueue preparing to switch ++ * @next: the task we are going to switch to. ++ * ++ * This is called with the rq lock held and interrupts off. It must ++ * be paired with a subsequent finish_task_switch after the context ++ * switch. ++ * ++ * prepare_task_switch sets up locking and calls architecture specific ++ * hooks. ++ */ ++static inline void ++prepare_task_switch(struct rq *rq, struct task_struct *prev, ++ struct task_struct *next) ++{ ++ kcov_prepare_switch(prev); ++ sched_info_switch(rq, prev, next); ++ perf_event_task_sched_out(prev, next); ++ rseq_preempt(prev); ++ fire_sched_out_preempt_notifiers(prev, next); ++ prepare_task(next); ++ prepare_arch_switch(next); ++} ++ ++/** ++ * finish_task_switch - clean up after a task-switch ++ * @rq: runqueue associated with task-switch ++ * @prev: the thread we just switched away from. ++ * ++ * finish_task_switch must be called after the context switch, paired ++ * with a prepare_task_switch call before the context switch. ++ * finish_task_switch will reconcile locking set up by prepare_task_switch, ++ * and do any other architecture-specific cleanup actions. ++ * ++ * Note that we may have delayed dropping an mm in context_switch(). If ++ * so, we finish that here outside of the runqueue lock. (Doing it ++ * with the lock held can cause deadlocks; see schedule() for ++ * details.) ++ * ++ * The context switch have flipped the stack from under us and restored the ++ * local variables which were saved when this task called schedule() in the ++ * past. prev == current is still correct but we need to recalculate this_rq ++ * because prev may have moved to another CPU. ++ */ ++static void finish_task_switch(struct task_struct *prev) ++ __releases(rq->lock) ++{ ++ struct rq *rq = this_rq(); ++ struct mm_struct *mm = rq->prev_mm; ++ long prev_state; ++ ++ /* ++ * The previous task will have left us with a preempt_count of 2 ++ * because it left us after: ++ * ++ * schedule() ++ * preempt_disable(); // 1 ++ * __schedule() ++ * raw_spin_lock_irq(rq->lock) // 2 ++ * ++ * Also, see FORK_PREEMPT_COUNT. ++ */ ++ if (WARN_ONCE(preempt_count() != 2*PREEMPT_DISABLE_OFFSET, ++ "corrupted preempt_count: %s/%d/0x%x\n", ++ current->comm, current->pid, preempt_count())) ++ preempt_count_set(FORK_PREEMPT_COUNT); ++ ++ rq->prev_mm = NULL; ++ ++ /* ++ * A task struct has one reference for the use as "current". ++ * If a task dies, then it sets TASK_DEAD in tsk->state and calls ++ * schedule one last time. The schedule call will never return, and ++ * the scheduled task must drop that reference. ++ * ++ * We must observe prev->state before clearing prev->on_cpu (in ++ * finish_task), otherwise a concurrent wakeup can get prev ++ * running on another CPU and we could rave with its RUNNING -> DEAD ++ * transition, resulting in a double drop. ++ */ ++ prev_state = prev->state; ++ vtime_task_switch(prev); ++ perf_event_task_sched_in(prev, current); ++ finish_task(prev); ++ finish_lock_switch(rq, prev); ++ finish_arch_post_lock_switch(); ++ kcov_finish_switch(current); ++ ++ fire_sched_in_preempt_notifiers(current); ++ /* ++ * When switching through a kernel thread, the loop in ++ * membarrier_{private,global}_expedited() may have observed that ++ * kernel thread and not issued an IPI. It is therefore possible to ++ * schedule between user->kernel->user threads without passing though ++ * switch_mm(). Membarrier requires a barrier after storing to ++ * rq->curr, before returning to userspace, so provide them here: ++ * ++ * - a full memory barrier for {PRIVATE,GLOBAL}_EXPEDITED, implicitly ++ * provided by mmdrop(), ++ * - a sync_core for SYNC_CORE. ++ */ ++ if (mm) { ++ membarrier_mm_sync_core_before_usermode(mm); ++ mmdrop(mm); ++ } ++ if (unlikely(prev_state == TASK_DEAD)) { ++ /* ++ * Remove function-return probe instances associated with this ++ * task and put them back on the free list. ++ */ ++ kprobe_flush_task(prev); ++ ++ /* Task is done with its stack. */ ++ put_task_stack(prev); ++ ++ put_task_struct(prev); ++ } ++} ++ ++/** ++ * schedule_tail - first thing a freshly forked thread must call. ++ * @prev: the thread we just switched away from. ++ */ ++asmlinkage __visible void schedule_tail(struct task_struct *prev) ++{ ++ /* ++ * New tasks start with FORK_PREEMPT_COUNT, see there and ++ * finish_task_switch() for details. ++ * ++ * finish_task_switch() will drop rq->lock() and lower preempt_count ++ * and the preempt_enable() will end up enabling preemption (on ++ * PREEMPT_COUNT kernels). ++ */ ++ ++ finish_task_switch(prev); ++ preempt_enable(); ++ ++ if (current->set_child_tid) ++ put_user(task_pid_vnr(current), current->set_child_tid); ++ ++ calculate_sigpending(); ++} ++ ++/* ++ * context_switch - switch to the new MM and the new thread's register state. ++ */ ++static __always_inline void ++context_switch(struct rq *rq, struct task_struct *prev, ++ struct task_struct *next) ++{ ++ struct mm_struct *mm, *oldmm; ++ ++ prepare_task_switch(rq, prev, next); ++ ++ mm = next->mm; ++ oldmm = prev->active_mm; ++ /* ++ * For paravirt, this is coupled with an exit in switch_to to ++ * combine the page table reload and the switch backend into ++ * one hypercall. ++ */ ++ arch_start_context_switch(prev); ++ ++ /* ++ * If mm is non-NULL, we pass through switch_mm(). If mm is ++ * NULL, we will pass through mmdrop() in finish_task_switch(). ++ * Both of these contain the full memory barrier required by ++ * membarrier after storing to rq->curr, before returning to ++ * user-space. ++ */ ++ if (!mm) { ++ next->active_mm = oldmm; ++ mmgrab(oldmm); ++ enter_lazy_tlb(oldmm, next); ++ } else ++ switch_mm_irqs_off(oldmm, mm, next); ++ ++ if (!prev->mm) { ++ prev->active_mm = NULL; ++ rq->prev_mm = oldmm; ++ } ++ prepare_lock_switch(rq, next); ++ ++ /* Here we just switch the register state and the stack. */ ++ switch_to(prev, next, prev); ++ barrier(); ++ ++ finish_task_switch(prev); ++} ++ ++/* ++ * nr_running, nr_uninterruptible and nr_context_switches: ++ * ++ * externally visible scheduler statistics: current number of runnable ++ * threads, total number of context switches performed since bootup. ++ */ ++unsigned long nr_running(void) ++{ ++ unsigned long i, sum = 0; ++ ++ for_each_online_cpu(i) ++ sum += cpu_rq(i)->nr_running; ++ ++ return sum; ++} ++ ++static unsigned long nr_uninterruptible(void) ++{ ++ unsigned long i, sum = 0; ++ ++ for_each_online_cpu(i) ++ sum += cpu_rq(i)->nr_uninterruptible; ++ ++ return sum; ++} ++ ++/* ++ * Check if only the current task is running on the CPU. ++ * ++ * Caution: this function does not check that the caller has disabled ++ * preemption, thus the result might have a time-of-check-to-time-of-use ++ * race. The caller is responsible to use it correctly, for example: ++ * ++ * - from a non-preemptable section (of course) ++ * ++ * - from a thread that is bound to a single CPU ++ * ++ * - in a loop with very short iterations (e.g. a polling loop) ++ */ ++bool single_task_running(void) ++{ ++ struct rq *rq = cpu_rq(smp_processor_id()); ++ ++ if (rq_load(rq) == 1) ++ return true; ++ else ++ return false; ++} ++EXPORT_SYMBOL(single_task_running); ++ ++unsigned long long nr_context_switches(void) ++{ ++ int i; ++ unsigned long long sum = 0; ++ ++ for_each_possible_cpu(i) ++ sum += cpu_rq(i)->nr_switches; ++ ++ return sum; ++} ++ ++/* ++ * IO-wait accounting, and how its mostly bollocks (on SMP). ++ * ++ * The idea behind IO-wait account is to account the idle time that we could ++ * have spend running if it were not for IO. That is, if we were to improve the ++ * storage performance, we'd have a proportional reduction in IO-wait time. ++ * ++ * This all works nicely on UP, where, when a task blocks on IO, we account ++ * idle time as IO-wait, because if the storage were faster, it could've been ++ * running and we'd not be idle. ++ * ++ * This has been extended to SMP, by doing the same for each CPU. This however ++ * is broken. ++ * ++ * Imagine for instance the case where two tasks block on one CPU, only the one ++ * CPU will have IO-wait accounted, while the other has regular idle. Even ++ * though, if the storage were faster, both could've ran at the same time, ++ * utilising both CPUs. ++ * ++ * This means, that when looking globally, the current IO-wait accounting on ++ * SMP is a lower bound, by reason of under accounting. ++ * ++ * Worse, since the numbers are provided per CPU, they are sometimes ++ * interpreted per CPU, and that is nonsensical. A blocked task isn't strictly ++ * associated with any one particular CPU, it can wake to another CPU than it ++ * blocked on. This means the per CPU IO-wait number is meaningless. ++ * ++ * Task CPU affinities can make all that even more 'interesting'. ++ */ ++ ++unsigned long nr_iowait(void) ++{ ++ unsigned long i, sum = 0; ++ ++ for_each_possible_cpu(i) ++ sum += atomic_read(&cpu_rq(i)->nr_iowait); ++ ++ return sum; ++} ++ ++/* ++ * Consumers of these two interfaces, like for example the cpufreq menu ++ * governor are using nonsensical data. Boosting frequency for a CPU that has ++ * IO-wait which might not even end up running the task when it does become ++ * runnable. ++ */ ++ ++unsigned long nr_iowait_cpu(int cpu) ++{ ++ struct rq *this = cpu_rq(cpu); ++ return atomic_read(&this->nr_iowait); ++} ++ ++unsigned long nr_active(void) ++{ ++ return nr_running() + nr_uninterruptible(); ++} ++ ++/* ++ * I/O wait is the number of running or queued tasks with their ->rq pointer ++ * set to this cpu as being the CPU they're more likely to run on. ++ */ ++void get_iowait_load(unsigned long *nr_waiters, unsigned long *load) ++{ ++ struct rq *rq = this_rq(); ++ ++ *nr_waiters = atomic_read(&rq->nr_iowait); ++ *load = rq_load(rq); ++} ++ ++/* Variables and functions for calc_load */ ++static unsigned long calc_load_update; ++unsigned long avenrun[3]; ++EXPORT_SYMBOL(avenrun); ++ ++/** ++ * get_avenrun - get the load average array ++ * @loads: pointer to dest load array ++ * @offset: offset to add ++ * @shift: shift count to shift the result left ++ * ++ * These values are estimates at best, so no need for locking. ++ */ ++void get_avenrun(unsigned long *loads, unsigned long offset, int shift) ++{ ++ loads[0] = (avenrun[0] + offset) << shift; ++ loads[1] = (avenrun[1] + offset) << shift; ++ loads[2] = (avenrun[2] + offset) << shift; ++} ++ ++static unsigned long ++calc_load(unsigned long load, unsigned long exp, unsigned long active) ++{ ++ unsigned long newload; ++ ++ newload = load * exp + active * (FIXED_1 - exp); ++ if (active >= load) ++ newload += FIXED_1-1; ++ ++ return newload / FIXED_1; ++} ++ ++/* ++ * calc_load - update the avenrun load estimates every LOAD_FREQ seconds. ++ */ ++void calc_global_load(unsigned long ticks) ++{ ++ long active; ++ ++ if (time_before(jiffies, READ_ONCE(calc_load_update))) ++ return; ++ active = nr_active() * FIXED_1; ++ ++ avenrun[0] = calc_load(avenrun[0], EXP_1, active); ++ avenrun[1] = calc_load(avenrun[1], EXP_5, active); ++ avenrun[2] = calc_load(avenrun[2], EXP_15, active); ++ ++ calc_load_update = jiffies + LOAD_FREQ; ++} ++ ++DEFINE_PER_CPU(struct kernel_stat, kstat); ++DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat); ++ ++EXPORT_PER_CPU_SYMBOL(kstat); ++EXPORT_PER_CPU_SYMBOL(kernel_cpustat); ++ ++#ifdef CONFIG_PARAVIRT ++static inline u64 steal_ticks(u64 steal) ++{ ++ if (unlikely(steal > NSEC_PER_SEC)) ++ return div_u64(steal, TICK_NSEC); ++ ++ return __iter_div_u64_rem(steal, TICK_NSEC, &steal); ++} ++#endif ++ ++#ifndef nsecs_to_cputime ++# define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs) ++#endif ++ ++/* ++ * On each tick, add the number of nanoseconds to the unbanked variables and ++ * once one tick's worth has accumulated, account it allowing for accurate ++ * sub-tick accounting and totals. Use the TICK_APPROX_NS to match the way we ++ * deduct nanoseconds. ++ */ ++static void pc_idle_time(struct rq *rq, struct task_struct *idle, unsigned long ns) ++{ ++ u64 *cpustat = kcpustat_this_cpu->cpustat; ++ unsigned long ticks; ++ ++ if (atomic_read(&rq->nr_iowait) > 0) { ++ rq->iowait_ns += ns; ++ if (rq->iowait_ns >= JIFFY_NS) { ++ ticks = NS_TO_JIFFIES(rq->iowait_ns); ++ cpustat[CPUTIME_IOWAIT] += (__force u64)TICK_APPROX_NS * ticks; ++ rq->iowait_ns %= JIFFY_NS; ++ } ++ } else { ++ rq->idle_ns += ns; ++ if (rq->idle_ns >= JIFFY_NS) { ++ ticks = NS_TO_JIFFIES(rq->idle_ns); ++ cpustat[CPUTIME_IDLE] += (__force u64)TICK_APPROX_NS * ticks; ++ rq->idle_ns %= JIFFY_NS; ++ } ++ } ++ acct_update_integrals(idle); ++} ++ ++static void pc_system_time(struct rq *rq, struct task_struct *p, ++ int hardirq_offset, unsigned long ns) ++{ ++ u64 *cpustat = kcpustat_this_cpu->cpustat; ++ unsigned long ticks; ++ ++ p->stime_ns += ns; ++ if (p->stime_ns >= JIFFY_NS) { ++ ticks = NS_TO_JIFFIES(p->stime_ns); ++ p->stime_ns %= JIFFY_NS; ++ p->stime += (__force u64)TICK_APPROX_NS * ticks; ++ account_group_system_time(p, TICK_APPROX_NS * ticks); ++ } ++ p->sched_time += ns; ++ account_group_exec_runtime(p, ns); ++ ++ if (hardirq_count() - hardirq_offset) { ++ rq->irq_ns += ns; ++ if (rq->irq_ns >= JIFFY_NS) { ++ ticks = NS_TO_JIFFIES(rq->irq_ns); ++ cpustat[CPUTIME_IRQ] += (__force u64)TICK_APPROX_NS * ticks; ++ rq->irq_ns %= JIFFY_NS; ++ } ++ } else if (in_serving_softirq()) { ++ rq->softirq_ns += ns; ++ if (rq->softirq_ns >= JIFFY_NS) { ++ ticks = NS_TO_JIFFIES(rq->softirq_ns); ++ cpustat[CPUTIME_SOFTIRQ] += (__force u64)TICK_APPROX_NS * ticks; ++ rq->softirq_ns %= JIFFY_NS; ++ } ++ } else { ++ rq->system_ns += ns; ++ if (rq->system_ns >= JIFFY_NS) { ++ ticks = NS_TO_JIFFIES(rq->system_ns); ++ cpustat[CPUTIME_SYSTEM] += (__force u64)TICK_APPROX_NS * ticks; ++ rq->system_ns %= JIFFY_NS; ++ } ++ } ++ acct_update_integrals(p); ++} ++ ++static void pc_user_time(struct rq *rq, struct task_struct *p, unsigned long ns) ++{ ++ u64 *cpustat = kcpustat_this_cpu->cpustat; ++ unsigned long ticks; ++ ++ p->utime_ns += ns; ++ if (p->utime_ns >= JIFFY_NS) { ++ ticks = NS_TO_JIFFIES(p->utime_ns); ++ p->utime_ns %= JIFFY_NS; ++ p->utime += (__force u64)TICK_APPROX_NS * ticks; ++ account_group_user_time(p, TICK_APPROX_NS * ticks); ++ } ++ p->sched_time += ns; ++ account_group_exec_runtime(p, ns); ++ ++ if (this_cpu_ksoftirqd() == p) { ++ /* ++ * ksoftirqd time do not get accounted in cpu_softirq_time. ++ * So, we have to handle it separately here. ++ */ ++ rq->softirq_ns += ns; ++ if (rq->softirq_ns >= JIFFY_NS) { ++ ticks = NS_TO_JIFFIES(rq->softirq_ns); ++ cpustat[CPUTIME_SOFTIRQ] += (__force u64)TICK_APPROX_NS * ticks; ++ rq->softirq_ns %= JIFFY_NS; ++ } ++ } ++ ++ if (task_nice(p) > 0 || idleprio_task(p)) { ++ rq->nice_ns += ns; ++ if (rq->nice_ns >= JIFFY_NS) { ++ ticks = NS_TO_JIFFIES(rq->nice_ns); ++ cpustat[CPUTIME_NICE] += (__force u64)TICK_APPROX_NS * ticks; ++ rq->nice_ns %= JIFFY_NS; ++ } ++ } else { ++ rq->user_ns += ns; ++ if (rq->user_ns >= JIFFY_NS) { ++ ticks = NS_TO_JIFFIES(rq->user_ns); ++ cpustat[CPUTIME_USER] += (__force u64)TICK_APPROX_NS * ticks; ++ rq->user_ns %= JIFFY_NS; ++ } ++ } ++ acct_update_integrals(p); ++} ++ ++/* ++ * This is called on clock ticks. ++ * Bank in p->sched_time the ns elapsed since the last tick or switch. ++ * CPU scheduler quota accounting is also performed here in microseconds. ++ */ ++static void update_cpu_clock_tick(struct rq *rq, struct task_struct *p) ++{ ++ s64 account_ns = rq->niffies - p->last_ran; ++ struct task_struct *idle = rq->idle; ++ ++ /* Accurate tick timekeeping */ ++ if (user_mode(get_irq_regs())) ++ pc_user_time(rq, p, account_ns); ++ else if (p != idle || (irq_count() != HARDIRQ_OFFSET)) { ++ pc_system_time(rq, p, HARDIRQ_OFFSET, account_ns); ++ } else ++ pc_idle_time(rq, idle, account_ns); ++ ++ /* time_slice accounting is done in usecs to avoid overflow on 32bit */ ++ if (p->policy != SCHED_FIFO && p != idle) ++ p->time_slice -= NS_TO_US(account_ns); ++ ++ p->last_ran = rq->niffies; ++} ++ ++/* ++ * This is called on context switches. ++ * Bank in p->sched_time the ns elapsed since the last tick or switch. ++ * CPU scheduler quota accounting is also performed here in microseconds. ++ */ ++static void update_cpu_clock_switch(struct rq *rq, struct task_struct *p) ++{ ++ s64 account_ns = rq->niffies - p->last_ran; ++ struct task_struct *idle = rq->idle; ++ ++ /* Accurate subtick timekeeping */ ++ if (p != idle) ++ pc_user_time(rq, p, account_ns); ++ else ++ pc_idle_time(rq, idle, account_ns); ++ ++ /* time_slice accounting is done in usecs to avoid overflow on 32bit */ ++ if (p->policy != SCHED_FIFO && p != idle) ++ p->time_slice -= NS_TO_US(account_ns); ++} ++ ++/* ++ * Return any ns on the sched_clock that have not yet been accounted in ++ * @p in case that task is currently running. ++ * ++ * Called with task_rq_lock(p) held. ++ */ ++static inline u64 do_task_delta_exec(struct task_struct *p, struct rq *rq) ++{ ++ u64 ns = 0; ++ ++ /* ++ * Must be ->curr _and_ ->on_rq. If dequeued, we would ++ * project cycles that may never be accounted to this ++ * thread, breaking clock_gettime(). ++ */ ++ if (p == rq->curr && task_on_rq_queued(p)) { ++ update_clocks(rq); ++ ns = rq->niffies - p->last_ran; ++ } ++ ++ return ns; ++} ++ ++/* ++ * Return accounted runtime for the task. ++ * Return separately the current's pending runtime that have not been ++ * accounted yet. ++ * ++ */ ++unsigned long long task_sched_runtime(struct task_struct *p) ++{ ++ unsigned long flags; ++ struct rq *rq; ++ u64 ns; ++ ++#if defined(CONFIG_64BIT) && defined(CONFIG_SMP) ++ /* ++ * 64-bit doesn't need locks to atomically read a 64-bit value. ++ * So we have a optimisation chance when the task's delta_exec is 0. ++ * Reading ->on_cpu is racy, but this is ok. ++ * ++ * If we race with it leaving CPU, we'll take a lock. So we're correct. ++ * If we race with it entering CPU, unaccounted time is 0. This is ++ * indistinguishable from the read occurring a few cycles earlier. ++ * If we see ->on_cpu without ->on_rq, the task is leaving, and has ++ * been accounted, so we're correct here as well. ++ */ ++ if (!p->on_cpu || !task_on_rq_queued(p)) ++ return tsk_seruntime(p); ++#endif ++ ++ rq = task_rq_lock(p, &flags); ++ ns = p->sched_time + do_task_delta_exec(p, rq); ++ task_rq_unlock(rq, p, &flags); ++ ++ return ns; ++} ++ ++/* ++ * Functions to test for when SCHED_ISO tasks have used their allocated ++ * quota as real time scheduling and convert them back to SCHED_NORMAL. All ++ * data is modified only by the local runqueue during scheduler_tick with ++ * interrupts disabled. ++ */ ++ ++/* ++ * Test if SCHED_ISO tasks have run longer than their alloted period as RT ++ * tasks and set the refractory flag if necessary. There is 10% hysteresis ++ * for unsetting the flag. 115/128 is ~90/100 as a fast shift instead of a ++ * slow division. ++ */ ++static inline void iso_tick(struct rq *rq) ++{ ++ rq->iso_ticks = rq->iso_ticks * (ISO_PERIOD - 1) / ISO_PERIOD; ++ rq->iso_ticks += 100; ++ if (rq->iso_ticks > ISO_PERIOD * sched_iso_cpu) { ++ rq->iso_refractory = true; ++ if (unlikely(rq->iso_ticks > ISO_PERIOD * 100)) ++ rq->iso_ticks = ISO_PERIOD * 100; ++ } ++} ++ ++/* No SCHED_ISO task was running so decrease rq->iso_ticks */ ++static inline void no_iso_tick(struct rq *rq, int ticks) ++{ ++ if (rq->iso_ticks > 0 || rq->iso_refractory) { ++ rq->iso_ticks = rq->iso_ticks * (ISO_PERIOD - ticks) / ISO_PERIOD; ++ if (rq->iso_ticks < ISO_PERIOD * (sched_iso_cpu * 115 / 128)) { ++ rq->iso_refractory = false; ++ if (unlikely(rq->iso_ticks < 0)) ++ rq->iso_ticks = 0; ++ } ++ } ++} ++ ++/* This manages tasks that have run out of timeslice during a scheduler_tick */ ++static void task_running_tick(struct rq *rq) ++{ ++ struct task_struct *p = rq->curr; ++ ++ /* ++ * If a SCHED_ISO task is running we increment the iso_ticks. In ++ * order to prevent SCHED_ISO tasks from causing starvation in the ++ * presence of true RT tasks we account those as iso_ticks as well. ++ */ ++ if (rt_task(p) || task_running_iso(p)) ++ iso_tick(rq); ++ else ++ no_iso_tick(rq, 1); ++ ++ /* SCHED_FIFO tasks never run out of timeslice. */ ++ if (p->policy == SCHED_FIFO) ++ return; ++ ++ if (iso_task(p)) { ++ if (task_running_iso(p)) { ++ if (rq->iso_refractory) { ++ /* ++ * SCHED_ISO task is running as RT and limit ++ * has been hit. Force it to reschedule as ++ * SCHED_NORMAL by zeroing its time_slice ++ */ ++ p->time_slice = 0; ++ } ++ } else if (!rq->iso_refractory) { ++ /* Can now run again ISO. Reschedule to pick up prio */ ++ goto out_resched; ++ } ++ } ++ ++ /* ++ * Tasks that were scheduled in the first half of a tick are not ++ * allowed to run into the 2nd half of the next tick if they will ++ * run out of time slice in the interim. Otherwise, if they have ++ * less than RESCHED_US μs of time slice left they will be rescheduled. ++ * Dither is used as a backup for when hrexpiry is disabled or high res ++ * timers not configured in. ++ */ ++ if (p->time_slice - rq->dither >= RESCHED_US) ++ return; ++out_resched: ++ rq_lock(rq); ++ __set_tsk_resched(p); ++ rq_unlock(rq); ++} ++ ++static inline void task_tick(struct rq *rq) ++{ ++ if (!rq_idle(rq)) ++ task_running_tick(rq); ++ else if (rq->last_jiffy > rq->last_scheduler_tick) ++ no_iso_tick(rq, rq->last_jiffy - rq->last_scheduler_tick); ++} ++ ++#ifdef CONFIG_NO_HZ_FULL ++/* ++ * We can stop the timer tick any time highres timers are active since ++ * we rely entirely on highres timeouts for task expiry rescheduling. ++ */ ++static void sched_stop_tick(struct rq *rq, int cpu) ++{ ++ if (!hrexpiry_enabled(rq)) ++ return; ++ if (!tick_nohz_full_enabled()) ++ return; ++ if (!tick_nohz_full_cpu(cpu)) ++ return; ++ tick_nohz_dep_clear_cpu(cpu, TICK_DEP_BIT_SCHED); ++} ++ ++static inline void sched_start_tick(struct rq *rq, int cpu) ++{ ++ tick_nohz_dep_set_cpu(cpu, TICK_DEP_BIT_SCHED); ++} ++ ++struct tick_work { ++ int cpu; ++ struct delayed_work work; ++}; ++ ++static struct tick_work __percpu *tick_work_cpu; ++ ++static void sched_tick_remote(struct work_struct *work) ++{ ++ struct delayed_work *dwork = to_delayed_work(work); ++ struct tick_work *twork = container_of(dwork, struct tick_work, work); ++ int cpu = twork->cpu; ++ struct rq *rq = cpu_rq(cpu); ++ struct task_struct *curr; ++ u64 delta; ++ ++ /* ++ * Handle the tick only if it appears the remote CPU is running in full ++ * dynticks mode. The check is racy by nature, but missing a tick or ++ * having one too much is no big deal because the scheduler tick updates ++ * statistics and checks timeslices in a time-independent way, regardless ++ * of when exactly it is running. ++ */ ++ if (idle_cpu(cpu) || !tick_nohz_tick_stopped_cpu(cpu)) ++ goto out_requeue; ++ ++ rq_lock_irq(rq); ++ curr = rq->curr; ++ if (is_idle_task(curr)) ++ goto out_unlock; ++ ++ update_rq_clock(rq); ++ delta = rq_clock_task(rq) - curr->last_ran; ++ ++ /* ++ * Make sure the next tick runs within a reasonable ++ * amount of time. ++ */ ++ WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 3); ++ task_tick(rq); ++ ++out_unlock: ++ rq_unlock_irq(rq); ++ ++out_requeue: ++ /* ++ * Run the remote tick once per second (1Hz). This arbitrary ++ * frequency is large enough to avoid overload but short enough ++ * to keep scheduler internal stats reasonably up to date. ++ */ ++ queue_delayed_work(system_unbound_wq, dwork, HZ); ++} ++ ++static void sched_tick_start(int cpu) ++{ ++ struct tick_work *twork; ++ ++ if (housekeeping_cpu(cpu, HK_FLAG_TICK)) ++ return; ++ ++ WARN_ON_ONCE(!tick_work_cpu); ++ ++ twork = per_cpu_ptr(tick_work_cpu, cpu); ++ twork->cpu = cpu; ++ INIT_DELAYED_WORK(&twork->work, sched_tick_remote); ++ queue_delayed_work(system_unbound_wq, &twork->work, HZ); ++} ++ ++#ifdef CONFIG_HOTPLUG_CPU ++static void sched_tick_stop(int cpu) ++{ ++ struct tick_work *twork; ++ ++ if (housekeeping_cpu(cpu, HK_FLAG_TICK)) ++ return; ++ ++ WARN_ON_ONCE(!tick_work_cpu); ++ ++ twork = per_cpu_ptr(tick_work_cpu, cpu); ++ cancel_delayed_work_sync(&twork->work); ++} ++#endif /* CONFIG_HOTPLUG_CPU */ ++ ++int __init sched_tick_offload_init(void) ++{ ++ tick_work_cpu = alloc_percpu(struct tick_work); ++ BUG_ON(!tick_work_cpu); ++ ++ return 0; ++} ++ ++#else /* !CONFIG_NO_HZ_FULL */ ++static inline void sched_stop_tick(struct rq *rq, int cpu) {} ++static inline void sched_start_tick(struct rq *rq, int cpu) {} ++static inline void sched_tick_start(int cpu) { } ++static inline void sched_tick_stop(int cpu) { } ++#endif ++ ++/* ++ * This function gets called by the timer code, with HZ frequency. ++ * We call it with interrupts disabled. ++ */ ++void scheduler_tick(void) ++{ ++ int cpu __maybe_unused = smp_processor_id(); ++ struct rq *rq = cpu_rq(cpu); ++ ++ sched_clock_tick(); ++ update_clocks(rq); ++ update_load_avg(rq, 0); ++ update_cpu_clock_tick(rq, rq->curr); ++ task_tick(rq); ++ rq->last_scheduler_tick = rq->last_jiffy; ++ rq->last_tick = rq->clock; ++ perf_event_task_tick(); ++ sched_stop_tick(rq, cpu); ++} ++ ++#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ ++ defined(CONFIG_TRACE_PREEMPT_TOGGLE)) ++/* ++ * If the value passed in is equal to the current preempt count ++ * then we just disabled preemption. Start timing the latency. ++ */ ++static inline void preempt_latency_start(int val) ++{ ++ if (preempt_count() == val) { ++ unsigned long ip = get_lock_parent_ip(); ++#ifdef CONFIG_DEBUG_PREEMPT ++ current->preempt_disable_ip = ip; ++#endif ++ trace_preempt_off(CALLER_ADDR0, ip); ++ } ++} ++ ++void preempt_count_add(int val) ++{ ++#ifdef CONFIG_DEBUG_PREEMPT ++ /* ++ * Underflow? ++ */ ++ if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) ++ return; ++#endif ++ __preempt_count_add(val); ++#ifdef CONFIG_DEBUG_PREEMPT ++ /* ++ * Spinlock count overflowing soon? ++ */ ++ DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= ++ PREEMPT_MASK - 10); ++#endif ++ preempt_latency_start(val); ++} ++EXPORT_SYMBOL(preempt_count_add); ++NOKPROBE_SYMBOL(preempt_count_add); ++ ++/* ++ * If the value passed in equals to the current preempt count ++ * then we just enabled preemption. Stop timing the latency. ++ */ ++static inline void preempt_latency_stop(int val) ++{ ++ if (preempt_count() == val) ++ trace_preempt_on(CALLER_ADDR0, get_lock_parent_ip()); ++} ++ ++void preempt_count_sub(int val) ++{ ++#ifdef CONFIG_DEBUG_PREEMPT ++ /* ++ * Underflow? ++ */ ++ if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) ++ return; ++ /* ++ * Is the spinlock portion underflowing? ++ */ ++ if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && ++ !(preempt_count() & PREEMPT_MASK))) ++ return; ++#endif ++ ++ preempt_latency_stop(val); ++ __preempt_count_sub(val); ++} ++EXPORT_SYMBOL(preempt_count_sub); ++NOKPROBE_SYMBOL(preempt_count_sub); ++ ++#else ++static inline void preempt_latency_start(int val) { } ++static inline void preempt_latency_stop(int val) { } ++#endif ++ ++static inline unsigned long get_preempt_disable_ip(struct task_struct *p) ++{ ++#ifdef CONFIG_DEBUG_PREEMPT ++ return p->preempt_disable_ip; ++#else ++ return 0; ++#endif ++} ++ ++/* ++ * The time_slice is only refilled when it is empty and that is when we set a ++ * new deadline. Make sure update_clocks has been called recently to update ++ * rq->niffies. ++ */ ++static void time_slice_expired(struct task_struct *p, struct rq *rq) ++{ ++ p->time_slice = timeslice(); ++ p->deadline = rq->niffies + task_deadline_diff(p); ++#ifdef CONFIG_SMT_NICE ++ if (!p->mm) ++ p->smt_bias = 0; ++ else if (rt_task(p)) ++ p->smt_bias = 1 << 30; ++ else if (task_running_iso(p)) ++ p->smt_bias = 1 << 29; ++ else if (idleprio_task(p)) { ++ if (task_running_idle(p)) ++ p->smt_bias = 0; ++ else ++ p->smt_bias = 1; ++ } else if (--p->smt_bias < 1) ++ p->smt_bias = MAX_PRIO - p->static_prio; ++#endif ++} ++ ++/* ++ * Timeslices below RESCHED_US are considered as good as expired as there's no ++ * point rescheduling when there's so little time left. SCHED_BATCH tasks ++ * have been flagged be not latency sensitive and likely to be fully CPU ++ * bound so every time they're rescheduled they have their time_slice ++ * refilled, but get a new later deadline to have little effect on ++ * SCHED_NORMAL tasks. ++ ++ */ ++static inline void check_deadline(struct task_struct *p, struct rq *rq) ++{ ++ if (p->time_slice < RESCHED_US || batch_task(p)) ++ time_slice_expired(p, rq); ++} ++ ++/* ++ * Task selection with skiplists is a simple matter of picking off the first ++ * task in the sorted list, an O(1) operation. The lookup is amortised O(1) ++ * being bound to the number of processors. ++ * ++ * Runqueues are selectively locked based on their unlocked data and then ++ * unlocked if not needed. At most 3 locks will be held at any time and are ++ * released as soon as they're no longer needed. All balancing between CPUs ++ * is thus done here in an extremely simple first come best fit manner. ++ * ++ * This iterates over runqueues in cache locality order. In interactive mode ++ * it iterates over all CPUs and finds the task with the best key/deadline. ++ * In non-interactive mode it will only take a task if it's from the current ++ * runqueue or a runqueue with more tasks than the current one with a better ++ * key/deadline. ++ */ ++#ifdef CONFIG_SMP ++static inline struct task_struct ++*earliest_deadline_task(struct rq *rq, int cpu, struct task_struct *idle) ++{ ++ struct rq *locked = NULL, *chosen = NULL; ++ struct task_struct *edt = idle; ++ int i, best_entries = 0; ++ u64 best_key = ~0ULL; ++ ++ for (i = 0; i < total_runqueues; i++) { ++ struct rq *other_rq = rq_order(rq, i); ++ skiplist_node *next; ++ int entries; ++ ++ entries = other_rq->sl->entries; ++ /* ++ * Check for queued entres lockless first. The local runqueue ++ * is locked so entries will always be accurate. ++ */ ++ if (!sched_interactive) { ++ /* ++ * Don't reschedule balance across nodes unless the CPU ++ * is idle. ++ */ ++ if (edt != idle && rq->cpu_locality[other_rq->cpu] > 3) ++ break; ++ if (entries <= best_entries) ++ continue; ++ } else if (!entries) ++ continue; ++ ++ /* if (i) implies other_rq != rq */ ++ if (i) { ++ /* Check for best id queued lockless first */ ++ if (other_rq->best_key >= best_key) ++ continue; ++ ++ if (unlikely(!trylock_rq(rq, other_rq))) ++ continue; ++ ++ /* Need to reevaluate entries after locking */ ++ entries = other_rq->sl->entries; ++ if (unlikely(!entries)) { ++ unlock_rq(other_rq); ++ continue; ++ } ++ } ++ ++ next = other_rq->node; ++ /* ++ * In interactive mode we check beyond the best entry on other ++ * runqueues if we can't get the best for smt or affinity ++ * reasons. ++ */ ++ while ((next = next->next[0]) != other_rq->node) { ++ struct task_struct *p; ++ u64 key = next->key; ++ ++ /* Reevaluate key after locking */ ++ if (key >= best_key) ++ break; ++ ++ p = next->value; ++ if (!smt_schedule(p, rq)) { ++ if (i && !sched_interactive) ++ break; ++ continue; ++ } ++ ++ if (sched_other_cpu(p, cpu)) { ++ if (sched_interactive || !i) ++ continue; ++ break; ++ } ++ /* Make sure affinity is ok */ ++ if (i) { ++ /* From this point on p is the best so far */ ++ if (locked) ++ unlock_rq(locked); ++ chosen = locked = other_rq; ++ } ++ best_entries = entries; ++ best_key = key; ++ edt = p; ++ break; ++ } ++ /* rq->preempting is a hint only as the state may have changed ++ * since it was set with the resched call but if we have met ++ * the condition we can break out here. */ ++ if (edt == rq->preempting) ++ break; ++ if (i && other_rq != chosen) ++ unlock_rq(other_rq); ++ } ++ ++ if (likely(edt != idle)) ++ take_task(rq, cpu, edt); ++ ++ if (locked) ++ unlock_rq(locked); ++ ++ rq->preempting = NULL; ++ ++ return edt; ++} ++#else /* CONFIG_SMP */ ++static inline struct task_struct ++*earliest_deadline_task(struct rq *rq, int cpu, struct task_struct *idle) ++{ ++ struct task_struct *edt; ++ ++ if (unlikely(!rq->sl->entries)) ++ return idle; ++ edt = rq->node->next[0]->value; ++ take_task(rq, cpu, edt); ++ return edt; ++} ++#endif /* CONFIG_SMP */ ++ ++/* ++ * Print scheduling while atomic bug: ++ */ ++static noinline void __schedule_bug(struct task_struct *prev) ++{ ++ /* Save this before calling printk(), since that will clobber it */ ++ unsigned long preempt_disable_ip = get_preempt_disable_ip(current); ++ ++ if (oops_in_progress) ++ return; ++ ++ printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", ++ prev->comm, prev->pid, preempt_count()); ++ ++ debug_show_held_locks(prev); ++ print_modules(); ++ if (irqs_disabled()) ++ print_irqtrace_events(prev); ++ if (IS_ENABLED(CONFIG_DEBUG_PREEMPT) ++ && in_atomic_preempt_off()) { ++ pr_err("Preemption disabled at:"); ++ print_ip_sym(preempt_disable_ip); ++ pr_cont("\n"); ++ } ++ dump_stack(); ++ add_taint(TAINT_WARN, LOCKDEP_STILL_OK); ++} ++ ++/* ++ * Various schedule()-time debugging checks and statistics: ++ */ ++static inline void schedule_debug(struct task_struct *prev) ++{ ++#ifdef CONFIG_SCHED_STACK_END_CHECK ++ if (task_stack_end_corrupted(prev)) ++ panic("corrupted stack end detected inside scheduler\n"); ++#endif ++ ++ if (unlikely(in_atomic_preempt_off())) { ++ __schedule_bug(prev); ++ preempt_count_set(PREEMPT_DISABLED); ++ } ++ rcu_sleep_check(); ++ ++ profile_hit(SCHED_PROFILING, __builtin_return_address(0)); ++ ++ schedstat_inc(this_rq()->sched_count); ++} ++ ++/* ++ * The currently running task's information is all stored in rq local data ++ * which is only modified by the local CPU. ++ */ ++static inline void set_rq_task(struct rq *rq, struct task_struct *p) ++{ ++ if (p == rq->idle || p->policy == SCHED_FIFO) ++ hrexpiry_clear(rq); ++ else ++ hrexpiry_start(rq, US_TO_NS(p->time_slice)); ++ if (rq->clock - rq->last_tick > HALF_JIFFY_NS) ++ rq->dither = 0; ++ else ++ rq->dither = rq_dither(rq); ++ ++ rq->rq_deadline = p->deadline; ++ rq->rq_prio = p->prio; ++#ifdef CONFIG_SMT_NICE ++ rq->rq_mm = p->mm; ++ rq->rq_smt_bias = p->smt_bias; ++#endif ++} ++ ++#ifdef CONFIG_SMT_NICE ++static void check_no_siblings(struct rq __maybe_unused *this_rq) {} ++static void wake_no_siblings(struct rq __maybe_unused *this_rq) {} ++static void (*check_siblings)(struct rq *this_rq) = &check_no_siblings; ++static void (*wake_siblings)(struct rq *this_rq) = &wake_no_siblings; ++ ++/* Iterate over smt siblings when we've scheduled a process on cpu and decide ++ * whether they should continue running or be descheduled. */ ++static void check_smt_siblings(struct rq *this_rq) ++{ ++ int other_cpu; ++ ++ for_each_cpu(other_cpu, &this_rq->thread_mask) { ++ struct task_struct *p; ++ struct rq *rq; ++ ++ rq = cpu_rq(other_cpu); ++ if (rq_idle(rq)) ++ continue; ++ p = rq->curr; ++ if (!smt_schedule(p, this_rq)) ++ resched_curr(rq); ++ } ++} ++ ++static void wake_smt_siblings(struct rq *this_rq) ++{ ++ int other_cpu; ++ ++ for_each_cpu(other_cpu, &this_rq->thread_mask) { ++ struct rq *rq; ++ ++ rq = cpu_rq(other_cpu); ++ if (rq_idle(rq)) ++ resched_idle(rq); ++ } ++} ++#else ++static void check_siblings(struct rq __maybe_unused *this_rq) {} ++static void wake_siblings(struct rq __maybe_unused *this_rq) {} ++#endif ++ ++/* ++ * schedule() is the main scheduler function. ++ * ++ * The main means of driving the scheduler and thus entering this function are: ++ * ++ * 1. Explicit blocking: mutex, semaphore, waitqueue, etc. ++ * ++ * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return ++ * paths. For example, see arch/x86/entry_64.S. ++ * ++ * To drive preemption between tasks, the scheduler sets the flag in timer ++ * interrupt handler scheduler_tick(). ++ * ++ * 3. Wakeups don't really cause entry into schedule(). They add a ++ * task to the run-queue and that's it. ++ * ++ * Now, if the new task added to the run-queue preempts the current ++ * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets ++ * called on the nearest possible occasion: ++ * ++ * - If the kernel is preemptible (CONFIG_PREEMPT=y): ++ * ++ * - in syscall or exception context, at the next outmost ++ * preempt_enable(). (this might be as soon as the wake_up()'s ++ * spin_unlock()!) ++ * ++ * - in IRQ context, return from interrupt-handler to ++ * preemptible context ++ * ++ * - If the kernel is not preemptible (CONFIG_PREEMPT is not set) ++ * then at the next: ++ * ++ * - cond_resched() call ++ * - explicit schedule() call ++ * - return from syscall or exception to user-space ++ * - return from interrupt-handler to user-space ++ * ++ * WARNING: must be called with preemption disabled! ++ */ ++static void __sched notrace __schedule(bool preempt) ++{ ++ struct task_struct *prev, *next, *idle; ++ unsigned long *switch_count; ++ bool deactivate = false; ++ struct rq *rq; ++ u64 niffies; ++ int cpu; ++ ++ cpu = smp_processor_id(); ++ rq = cpu_rq(cpu); ++ prev = rq->curr; ++ idle = rq->idle; ++ ++ schedule_debug(prev); ++ ++ local_irq_disable(); ++ rcu_note_context_switch(preempt); ++ ++ /* ++ * Make sure that signal_pending_state()->signal_pending() below ++ * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE) ++ * done by the caller to avoid the race with signal_wake_up(). ++ * ++ * The membarrier system call requires a full memory barrier ++ * after coming from user-space, before storing to rq->curr. ++ */ ++ rq_lock(rq); ++ smp_mb__after_spinlock(); ++#ifdef CONFIG_SMP ++ if (rq->preempt) { ++ /* ++ * Make sure resched_curr hasn't triggered a preemption ++ * locklessly on a task that has since scheduled away. Spurious ++ * wakeup of idle is okay though. ++ */ ++ if (unlikely(preempt && prev != idle && !test_tsk_need_resched(prev))) { ++ rq->preempt = NULL; ++ clear_preempt_need_resched(); ++ rq_unlock_irq(rq); ++ return; ++ } ++ rq->preempt = NULL; ++ } ++#endif ++ ++ switch_count = &prev->nivcsw; ++ if (!preempt && prev->state) { ++ if (unlikely(signal_pending_state(prev->state, prev))) { ++ prev->state = TASK_RUNNING; ++ } else { ++ deactivate = true; ++ prev->on_rq = 0; ++ ++ if (prev->in_iowait) { ++ atomic_inc(&rq->nr_iowait); ++ delayacct_blkio_start(); ++ } ++ ++ /* ++ * If a worker is going to sleep, notify and ++ * ask workqueue whether it wants to wake up a ++ * task to maintain concurrency. If so, wake ++ * up the task. ++ */ ++ if (prev->flags & PF_WQ_WORKER) { ++ struct task_struct *to_wakeup; ++ ++ to_wakeup = wq_worker_sleeping(prev); ++ if (to_wakeup) ++ try_to_wake_up_local(to_wakeup); ++ } ++ } ++ switch_count = &prev->nvcsw; ++ } ++ ++ /* ++ * Store the niffy value here for use by the next task's last_ran ++ * below to avoid losing niffies due to update_clocks being called ++ * again after this point. ++ */ ++ update_clocks(rq); ++ niffies = rq->niffies; ++ update_cpu_clock_switch(rq, prev); ++ ++ clear_tsk_need_resched(prev); ++ clear_preempt_need_resched(); ++ ++ if (idle != prev) { ++ check_deadline(prev, rq); ++ return_task(prev, rq, cpu, deactivate); ++ } ++ ++ next = earliest_deadline_task(rq, cpu, idle); ++ if (likely(next->prio != PRIO_LIMIT)) ++ clear_cpuidle_map(cpu); ++ else { ++ set_cpuidle_map(cpu); ++ update_load_avg(rq, 0); ++ } ++ ++ set_rq_task(rq, next); ++ next->last_ran = niffies; ++ ++ if (likely(prev != next)) { ++ /* ++ * Don't reschedule an idle task or deactivated tasks ++ */ ++ if (prev == idle) { ++ rq->nr_running++; ++ if (rt_task(next)) ++ rq->rt_nr_running++; ++ } else if (!deactivate) ++ resched_suitable_idle(prev); ++ if (unlikely(next == idle)) { ++ rq->nr_running--; ++ if (rt_task(prev)) ++ rq->rt_nr_running--; ++ wake_siblings(rq); ++ } else ++ check_siblings(rq); ++ rq->nr_switches++; ++ rq->curr = next; ++ /* ++ * The membarrier system call requires each architecture ++ * to have a full memory barrier after updating ++ * rq->curr, before returning to user-space. ++ * ++ * Here are the schemes providing that barrier on the ++ * various architectures: ++ * - mm ? switch_mm() : mmdrop() for x86, s390, sparc, PowerPC. ++ * switch_mm() rely on membarrier_arch_switch_mm() on PowerPC. ++ * - finish_lock_switch() for weakly-ordered ++ * architectures where spin_unlock is a full barrier, ++ * - switch_to() for arm64 (weakly-ordered, spin_unlock ++ * is a RELEASE barrier), ++ */ ++ ++*switch_count; ++ ++ trace_sched_switch(preempt, prev, next); ++ context_switch(rq, prev, next); /* unlocks the rq */ ++ } else { ++ check_siblings(rq); ++ rq_unlock(rq); ++ do_pending_softirq(rq, next); ++ local_irq_enable(); ++ } ++} ++ ++void __noreturn do_task_dead(void) ++{ ++ /* Causes final put_task_struct in finish_task_switch(). */ ++ set_special_state(TASK_DEAD); ++ ++ /* Tell freezer to ignore us: */ ++ current->flags |= PF_NOFREEZE; ++ __schedule(false); ++ BUG(); ++ ++ /* Avoid "noreturn function does return" - but don't continue if BUG() is a NOP: */ ++ for (;;) ++ cpu_relax(); ++} ++ ++static inline void sched_submit_work(struct task_struct *tsk) ++{ ++ if (!tsk->state || tsk_is_pi_blocked(tsk) || ++ preempt_count() || ++ signal_pending_state(tsk->state, tsk)) ++ return; ++ ++ /* ++ * If we are going to sleep and we have plugged IO queued, ++ * make sure to submit it to avoid deadlocks. ++ */ ++ if (blk_needs_flush_plug(tsk)) ++ blk_schedule_flush_plug(tsk); ++} ++ ++asmlinkage __visible void __sched schedule(void) ++{ ++ struct task_struct *tsk = current; ++ ++ sched_submit_work(tsk); ++ do { ++ preempt_disable(); ++ __schedule(false); ++ sched_preempt_enable_no_resched(); ++ } while (need_resched()); ++} ++ ++EXPORT_SYMBOL(schedule); ++ ++/* ++ * synchronize_rcu_tasks() makes sure that no task is stuck in preempted ++ * state (have scheduled out non-voluntarily) by making sure that all ++ * tasks have either left the run queue or have gone into user space. ++ * As idle tasks do not do either, they must not ever be preempted ++ * (schedule out non-voluntarily). ++ * ++ * schedule_idle() is similar to schedule_preempt_disable() except that it ++ * never enables preemption because it does not call sched_submit_work(). ++ */ ++void __sched schedule_idle(void) ++{ ++ /* ++ * As this skips calling sched_submit_work(), which the idle task does ++ * regardless because that function is a nop when the task is in a ++ * TASK_RUNNING state, make sure this isn't used someplace that the ++ * current task can be in any other state. Note, idle is always in the ++ * TASK_RUNNING state. ++ */ ++ WARN_ON_ONCE(current->state); ++ do { ++ __schedule(false); ++ } while (need_resched()); ++} ++ ++#ifdef CONFIG_CONTEXT_TRACKING ++asmlinkage __visible void __sched schedule_user(void) ++{ ++ /* ++ * If we come here after a random call to set_need_resched(), ++ * or we have been woken up remotely but the IPI has not yet arrived, ++ * we haven't yet exited the RCU idle mode. Do it here manually until ++ * we find a better solution. ++ * ++ * NB: There are buggy callers of this function. Ideally we ++ * should warn if prev_state != IN_USER, but that will trigger ++ * too frequently to make sense yet. ++ */ ++ enum ctx_state prev_state = exception_enter(); ++ schedule(); ++ exception_exit(prev_state); ++} ++#endif ++ ++/** ++ * schedule_preempt_disabled - called with preemption disabled ++ * ++ * Returns with preemption disabled. Note: preempt_count must be 1 ++ */ ++void __sched schedule_preempt_disabled(void) ++{ ++ sched_preempt_enable_no_resched(); ++ schedule(); ++ preempt_disable(); ++} ++ ++static void __sched notrace preempt_schedule_common(void) ++{ ++ do { ++ /* ++ * Because the function tracer can trace preempt_count_sub() ++ * and it also uses preempt_enable/disable_notrace(), if ++ * NEED_RESCHED is set, the preempt_enable_notrace() called ++ * by the function tracer will call this function again and ++ * cause infinite recursion. ++ * ++ * Preemption must be disabled here before the function ++ * tracer can trace. Break up preempt_disable() into two ++ * calls. One to disable preemption without fear of being ++ * traced. The other to still record the preemption latency, ++ * which can also be traced by the function tracer. ++ */ ++ preempt_disable_notrace(); ++ preempt_latency_start(1); ++ __schedule(true); ++ preempt_latency_stop(1); ++ preempt_enable_no_resched_notrace(); ++ ++ /* ++ * Check again in case we missed a preemption opportunity ++ * between schedule and now. ++ */ ++ } while (need_resched()); ++} ++ ++#ifdef CONFIG_PREEMPT ++/* ++ * this is the entry point to schedule() from in-kernel preemption ++ * off of preempt_enable. Kernel preemptions off return from interrupt ++ * occur there and call schedule directly. ++ */ ++asmlinkage __visible void __sched notrace preempt_schedule(void) ++{ ++ /* ++ * If there is a non-zero preempt_count or interrupts are disabled, ++ * we do not want to preempt the current task. Just return.. ++ */ ++ if (likely(!preemptible())) ++ return; ++ ++ preempt_schedule_common(); ++} ++NOKPROBE_SYMBOL(preempt_schedule); ++EXPORT_SYMBOL(preempt_schedule); ++ ++/** ++ * preempt_schedule_notrace - preempt_schedule called by tracing ++ * ++ * The tracing infrastructure uses preempt_enable_notrace to prevent ++ * recursion and tracing preempt enabling caused by the tracing ++ * infrastructure itself. But as tracing can happen in areas coming ++ * from userspace or just about to enter userspace, a preempt enable ++ * can occur before user_exit() is called. This will cause the scheduler ++ * to be called when the system is still in usermode. ++ * ++ * To prevent this, the preempt_enable_notrace will use this function ++ * instead of preempt_schedule() to exit user context if needed before ++ * calling the scheduler. ++ */ ++asmlinkage __visible void __sched notrace preempt_schedule_notrace(void) ++{ ++ enum ctx_state prev_ctx; ++ ++ if (likely(!preemptible())) ++ return; ++ ++ do { ++ /* ++ * Because the function tracer can trace preempt_count_sub() ++ * and it also uses preempt_enable/disable_notrace(), if ++ * NEED_RESCHED is set, the preempt_enable_notrace() called ++ * by the function tracer will call this function again and ++ * cause infinite recursion. ++ * ++ * Preemption must be disabled here before the function ++ * tracer can trace. Break up preempt_disable() into two ++ * calls. One to disable preemption without fear of being ++ * traced. The other to still record the preemption latency, ++ * which can also be traced by the function tracer. ++ */ ++ preempt_disable_notrace(); ++ preempt_latency_start(1); ++ /* ++ * Needs preempt disabled in case user_exit() is traced ++ * and the tracer calls preempt_enable_notrace() causing ++ * an infinite recursion. ++ */ ++ prev_ctx = exception_enter(); ++ __schedule(true); ++ exception_exit(prev_ctx); ++ ++ preempt_latency_stop(1); ++ preempt_enable_no_resched_notrace(); ++ } while (need_resched()); ++} ++EXPORT_SYMBOL_GPL(preempt_schedule_notrace); ++ ++#endif /* CONFIG_PREEMPT */ ++ ++/* ++ * this is the entry point to schedule() from kernel preemption ++ * off of irq context. ++ * Note, that this is called and return with irqs disabled. This will ++ * protect us against recursive calling from irq. ++ */ ++asmlinkage __visible void __sched preempt_schedule_irq(void) ++{ ++ enum ctx_state prev_state; ++ ++ /* Catch callers which need to be fixed */ ++ BUG_ON(preempt_count() || !irqs_disabled()); ++ ++ prev_state = exception_enter(); ++ ++ do { ++ preempt_disable(); ++ local_irq_enable(); ++ __schedule(true); ++ local_irq_disable(); ++ sched_preempt_enable_no_resched(); ++ } while (need_resched()); ++ ++ exception_exit(prev_state); ++} ++ ++int default_wake_function(wait_queue_entry_t *curr, unsigned mode, int wake_flags, ++ void *key) ++{ ++ return try_to_wake_up(curr->private, mode, wake_flags); ++} ++EXPORT_SYMBOL(default_wake_function); ++ ++#ifdef CONFIG_RT_MUTEXES ++ ++static inline int __rt_effective_prio(struct task_struct *pi_task, int prio) ++{ ++ if (pi_task) ++ prio = min(prio, pi_task->prio); ++ ++ return prio; ++} ++ ++static inline int rt_effective_prio(struct task_struct *p, int prio) ++{ ++ struct task_struct *pi_task = rt_mutex_get_top_task(p); ++ ++ return __rt_effective_prio(pi_task, prio); ++} ++ ++/* ++ * rt_mutex_setprio - set the current priority of a task ++ * @p: task to boost ++ * @pi_task: donor task ++ * ++ * This function changes the 'effective' priority of a task. It does ++ * not touch ->normal_prio like __setscheduler(). ++ * ++ * Used by the rt_mutex code to implement priority inheritance ++ * logic. Call site only calls if the priority of the task changed. ++ */ ++void rt_mutex_setprio(struct task_struct *p, struct task_struct *pi_task) ++{ ++ int prio, oldprio; ++ struct rq *rq; ++ ++ /* XXX used to be waiter->prio, not waiter->task->prio */ ++ prio = __rt_effective_prio(pi_task, p->normal_prio); ++ ++ /* ++ * If nothing changed; bail early. ++ */ ++ if (p->pi_top_task == pi_task && prio == p->prio) ++ return; ++ ++ rq = __task_rq_lock(p); ++ update_rq_clock(rq); ++ /* ++ * Set under pi_lock && rq->lock, such that the value can be used under ++ * either lock. ++ * ++ * Note that there is loads of tricky to make this pointer cache work ++ * right. rt_mutex_slowunlock()+rt_mutex_postunlock() work together to ++ * ensure a task is de-boosted (pi_task is set to NULL) before the ++ * task is allowed to run again (and can exit). This ensures the pointer ++ * points to a blocked task -- which guaratees the task is present. ++ */ ++ p->pi_top_task = pi_task; ++ ++ /* ++ * For FIFO/RR we only need to set prio, if that matches we're done. ++ */ ++ if (prio == p->prio) ++ goto out_unlock; ++ ++ /* ++ * Idle task boosting is a nono in general. There is one ++ * exception, when PREEMPT_RT and NOHZ is active: ++ * ++ * The idle task calls get_next_timer_interrupt() and holds ++ * the timer wheel base->lock on the CPU and another CPU wants ++ * to access the timer (probably to cancel it). We can safely ++ * ignore the boosting request, as the idle CPU runs this code ++ * with interrupts disabled and will complete the lock ++ * protected section without being interrupted. So there is no ++ * real need to boost. ++ */ ++ if (unlikely(p == rq->idle)) { ++ WARN_ON(p != rq->curr); ++ WARN_ON(p->pi_blocked_on); ++ goto out_unlock; ++ } ++ ++ trace_sched_pi_setprio(p, pi_task); ++ oldprio = p->prio; ++ p->prio = prio; ++ if (task_running(rq, p)){ ++ if (prio > oldprio) ++ resched_task(p); ++ } else if (task_queued(p)) { ++ dequeue_task(rq, p, DEQUEUE_SAVE); ++ enqueue_task(rq, p, ENQUEUE_RESTORE); ++ if (prio < oldprio) ++ try_preempt(p, rq); ++ } ++out_unlock: ++ __task_rq_unlock(rq); ++} ++#else ++static inline int rt_effective_prio(struct task_struct *p, int prio) ++{ ++ return prio; ++} ++#endif ++ ++/* ++ * Adjust the deadline for when the priority is to change, before it's ++ * changed. ++ */ ++static inline void adjust_deadline(struct task_struct *p, int new_prio) ++{ ++ p->deadline += static_deadline_diff(new_prio) - task_deadline_diff(p); ++} ++ ++void set_user_nice(struct task_struct *p, long nice) ++{ ++ int new_static, old_static; ++ unsigned long flags; ++ struct rq *rq; ++ ++ if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE) ++ return; ++ new_static = NICE_TO_PRIO(nice); ++ /* ++ * We have to be careful, if called from sys_setpriority(), ++ * the task might be in the middle of scheduling on another CPU. ++ */ ++ rq = task_rq_lock(p, &flags); ++ update_rq_clock(rq); ++ ++ /* ++ * The RT priorities are set via sched_setscheduler(), but we still ++ * allow the 'normal' nice value to be set - but as expected ++ * it wont have any effect on scheduling until the task is ++ * not SCHED_NORMAL/SCHED_BATCH: ++ */ ++ if (has_rt_policy(p)) { ++ p->static_prio = new_static; ++ goto out_unlock; ++ } ++ ++ adjust_deadline(p, new_static); ++ old_static = p->static_prio; ++ p->static_prio = new_static; ++ p->prio = effective_prio(p); ++ ++ if (task_queued(p)) { ++ dequeue_task(rq, p, DEQUEUE_SAVE); ++ enqueue_task(rq, p, ENQUEUE_RESTORE); ++ if (new_static < old_static) ++ try_preempt(p, rq); ++ } else if (task_running(rq, p)) { ++ set_rq_task(rq, p); ++ if (old_static < new_static) ++ resched_task(p); ++ } ++out_unlock: ++ task_rq_unlock(rq, p, &flags); ++} ++EXPORT_SYMBOL(set_user_nice); ++ ++/* ++ * can_nice - check if a task can reduce its nice value ++ * @p: task ++ * @nice: nice value ++ */ ++int can_nice(const struct task_struct *p, const int nice) ++{ ++ /* Convert nice value [19,-20] to rlimit style value [1,40] */ ++ int nice_rlim = nice_to_rlimit(nice); ++ ++ return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || ++ capable(CAP_SYS_NICE)); ++} ++ ++#ifdef __ARCH_WANT_SYS_NICE ++ ++/* ++ * sys_nice - change the priority of the current process. ++ * @increment: priority increment ++ * ++ * sys_setpriority is a more generic, but much slower function that ++ * does similar things. ++ */ ++SYSCALL_DEFINE1(nice, int, increment) ++{ ++ long nice, retval; ++ ++ /* ++ * Setpriority might change our priority at the same moment. ++ * We don't have to worry. Conceptually one call occurs first ++ * and we have a single winner. ++ */ ++ ++ increment = clamp(increment, -NICE_WIDTH, NICE_WIDTH); ++ nice = task_nice(current) + increment; ++ ++ nice = clamp_val(nice, MIN_NICE, MAX_NICE); ++ if (increment < 0 && !can_nice(current, nice)) ++ return -EPERM; ++ ++ retval = security_task_setnice(current, nice); ++ if (retval) ++ return retval; ++ ++ set_user_nice(current, nice); ++ return 0; ++} ++ ++#endif ++ ++/** ++ * task_prio - return the priority value of a given task. ++ * @p: the task in question. ++ * ++ * Return: The priority value as seen by users in /proc. ++ * RT tasks are offset by -100. Normal tasks are centered around 1, value goes ++ * from 0 (SCHED_ISO) up to 82 (nice +19 SCHED_IDLEPRIO). ++ */ ++int task_prio(const struct task_struct *p) ++{ ++ int delta, prio = p->prio - MAX_RT_PRIO; ++ ++ /* rt tasks and iso tasks */ ++ if (prio <= 0) ++ goto out; ++ ++ /* Convert to ms to avoid overflows */ ++ delta = NS_TO_MS(p->deadline - task_rq(p)->niffies); ++ if (unlikely(delta < 0)) ++ delta = 0; ++ delta = delta * 40 / ms_longest_deadline_diff(); ++ if (delta <= 80) ++ prio += delta; ++ if (idleprio_task(p)) ++ prio += 40; ++out: ++ return prio; ++} ++ ++/** ++ * idle_cpu - is a given CPU idle currently? ++ * @cpu: the processor in question. ++ * ++ * Return: 1 if the CPU is currently idle. 0 otherwise. ++ */ ++int idle_cpu(int cpu) ++{ ++ return cpu_curr(cpu) == cpu_rq(cpu)->idle; ++} ++ ++/** ++ * available_idle_cpu - is a given CPU idle for enqueuing work. ++ * @cpu: the CPU in question. ++ * ++ * Return: 1 if the CPU is currently idle. 0 otherwise. ++ */ ++int available_idle_cpu(int cpu) ++{ ++ if (!idle_cpu(cpu)) ++ return 0; ++ ++ if (vcpu_is_preempted(cpu)) ++ return 0; ++ ++ return 1; ++} ++ ++/** ++ * idle_task - return the idle task for a given CPU. ++ * @cpu: the processor in question. ++ * ++ * Return: The idle task for the CPU @cpu. ++ */ ++struct task_struct *idle_task(int cpu) ++{ ++ return cpu_rq(cpu)->idle; ++} ++ ++/** ++ * find_process_by_pid - find a process with a matching PID value. ++ * @pid: the pid in question. ++ * ++ * The task of @pid, if found. %NULL otherwise. ++ */ ++static inline struct task_struct *find_process_by_pid(pid_t pid) ++{ ++ return pid ? find_task_by_vpid(pid) : current; ++} ++ ++/* Actually do priority change: must hold rq lock. */ ++static void __setscheduler(struct task_struct *p, struct rq *rq, int policy, ++ int prio, bool keep_boost) ++{ ++ int oldrtprio, oldprio; ++ ++ p->policy = policy; ++ oldrtprio = p->rt_priority; ++ p->rt_priority = prio; ++ p->normal_prio = normal_prio(p); ++ oldprio = p->prio; ++ /* ++ * Keep a potential priority boosting if called from ++ * sched_setscheduler(). ++ */ ++ p->prio = normal_prio(p); ++ if (keep_boost) ++ p->prio = rt_effective_prio(p, p->prio); ++ ++ if (task_running(rq, p)) { ++ set_rq_task(rq, p); ++ resched_task(p); ++ } else if (task_queued(p)) { ++ dequeue_task(rq, p, DEQUEUE_SAVE); ++ enqueue_task(rq, p, ENQUEUE_RESTORE); ++ if (p->prio < oldprio || p->rt_priority > oldrtprio) ++ try_preempt(p, rq); ++ } ++} ++ ++/* ++ * Check the target process has a UID that matches the current process's ++ */ ++static bool check_same_owner(struct task_struct *p) ++{ ++ const struct cred *cred = current_cred(), *pcred; ++ bool match; ++ ++ rcu_read_lock(); ++ pcred = __task_cred(p); ++ match = (uid_eq(cred->euid, pcred->euid) || ++ uid_eq(cred->euid, pcred->uid)); ++ rcu_read_unlock(); ++ return match; ++} ++ ++static int __sched_setscheduler(struct task_struct *p, ++ const struct sched_attr *attr, ++ bool user, bool pi) ++{ ++ int retval, policy = attr->sched_policy, oldpolicy = -1, priority = attr->sched_priority; ++ unsigned long flags, rlim_rtprio = 0; ++ int reset_on_fork; ++ struct rq *rq; ++ ++ /* The pi code expects interrupts enabled */ ++ BUG_ON(pi && in_interrupt()); ++ ++ if (is_rt_policy(policy) && !capable(CAP_SYS_NICE)) { ++ unsigned long lflags; ++ ++ if (!lock_task_sighand(p, &lflags)) ++ return -ESRCH; ++ rlim_rtprio = task_rlimit(p, RLIMIT_RTPRIO); ++ unlock_task_sighand(p, &lflags); ++ if (rlim_rtprio) ++ goto recheck; ++ /* ++ * If the caller requested an RT policy without having the ++ * necessary rights, we downgrade the policy to SCHED_ISO. ++ * We also set the parameter to zero to pass the checks. ++ */ ++ policy = SCHED_ISO; ++ priority = 0; ++ } ++recheck: ++ /* Double check policy once rq lock held */ ++ if (policy < 0) { ++ reset_on_fork = p->sched_reset_on_fork; ++ policy = oldpolicy = p->policy; ++ } else { ++ reset_on_fork = !!(policy & SCHED_RESET_ON_FORK); ++ policy &= ~SCHED_RESET_ON_FORK; ++ ++ if (!SCHED_RANGE(policy)) ++ return -EINVAL; ++ } ++ ++ if (attr->sched_flags & ~(SCHED_FLAG_ALL | SCHED_FLAG_SUGOV)) ++ return -EINVAL; ++ ++ /* ++ * Valid priorities for SCHED_FIFO and SCHED_RR are ++ * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL and ++ * SCHED_BATCH is 0. ++ */ ++ if (priority < 0 || ++ (p->mm && priority > MAX_USER_RT_PRIO - 1) || ++ (!p->mm && priority > MAX_RT_PRIO - 1)) ++ return -EINVAL; ++ if (is_rt_policy(policy) != (priority != 0)) ++ return -EINVAL; ++ ++ /* ++ * Allow unprivileged RT tasks to decrease priority: ++ */ ++ if (user && !capable(CAP_SYS_NICE)) { ++ if (is_rt_policy(policy)) { ++ unsigned long rlim_rtprio = ++ task_rlimit(p, RLIMIT_RTPRIO); ++ ++ /* Can't set/change the rt policy */ ++ if (policy != p->policy && !rlim_rtprio) ++ return -EPERM; ++ ++ /* Can't increase priority */ ++ if (priority > p->rt_priority && ++ priority > rlim_rtprio) ++ return -EPERM; ++ } else { ++ switch (p->policy) { ++ /* ++ * Can only downgrade policies but not back to ++ * SCHED_NORMAL ++ */ ++ case SCHED_ISO: ++ if (policy == SCHED_ISO) ++ goto out; ++ if (policy != SCHED_NORMAL) ++ return -EPERM; ++ break; ++ case SCHED_BATCH: ++ if (policy == SCHED_BATCH) ++ goto out; ++ if (policy != SCHED_IDLEPRIO) ++ return -EPERM; ++ break; ++ case SCHED_IDLEPRIO: ++ if (policy == SCHED_IDLEPRIO) ++ goto out; ++ return -EPERM; ++ default: ++ break; ++ } ++ } ++ ++ /* Can't change other user's priorities */ ++ if (!check_same_owner(p)) ++ return -EPERM; ++ ++ /* Normal users shall not reset the sched_reset_on_fork flag: */ ++ if (p->sched_reset_on_fork && !reset_on_fork) ++ return -EPERM; ++ } ++ ++ if (user) { ++ retval = security_task_setscheduler(p); ++ if (retval) ++ return retval; ++ } ++ ++ /* ++ * Make sure no PI-waiters arrive (or leave) while we are ++ * changing the priority of the task: ++ * ++ * To be able to change p->policy safely, the runqueue lock must be ++ * held. ++ */ ++ rq = task_rq_lock(p, &flags); ++ update_rq_clock(rq); ++ ++ /* ++ * Changing the policy of the stop threads its a very bad idea: ++ */ ++ if (p == rq->stop) { ++ task_rq_unlock(rq, p, &flags); ++ return -EINVAL; ++ } ++ ++ /* ++ * If not changing anything there's no need to proceed further: ++ */ ++ if (unlikely(policy == p->policy && (!is_rt_policy(policy) || ++ priority == p->rt_priority))) { ++ task_rq_unlock(rq, p, &flags); ++ return 0; ++ } ++ ++ /* Re-check policy now with rq lock held */ ++ if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { ++ policy = oldpolicy = -1; ++ task_rq_unlock(rq, p, &flags); ++ goto recheck; ++ } ++ p->sched_reset_on_fork = reset_on_fork; ++ ++ __setscheduler(p, rq, policy, priority, pi); ++ task_rq_unlock(rq, p, &flags); ++ ++ if (pi) ++ rt_mutex_adjust_pi(p); ++out: ++ return 0; ++} ++ ++static int _sched_setscheduler(struct task_struct *p, int policy, ++ const struct sched_param *param, bool check) ++{ ++ struct sched_attr attr = { ++ .sched_policy = policy, ++ .sched_priority = param->sched_priority, ++ .sched_nice = PRIO_TO_NICE(p->static_prio), ++ }; ++ ++ return __sched_setscheduler(p, &attr, check, true); ++} ++/** ++ * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. ++ * @p: the task in question. ++ * @policy: new policy. ++ * @param: structure containing the new RT priority. ++ * ++ * Return: 0 on success. An error code otherwise. ++ * ++ * NOTE that the task may be already dead. ++ */ ++int sched_setscheduler(struct task_struct *p, int policy, ++ const struct sched_param *param) ++{ ++ return _sched_setscheduler(p, policy, param, true); ++} ++ ++EXPORT_SYMBOL_GPL(sched_setscheduler); ++ ++int sched_setattr(struct task_struct *p, const struct sched_attr *attr) ++{ ++ return __sched_setscheduler(p, attr, true, true); ++} ++EXPORT_SYMBOL_GPL(sched_setattr); ++ ++int sched_setattr_nocheck(struct task_struct *p, const struct sched_attr *attr) ++{ ++ return __sched_setscheduler(p, attr, false, true); ++} ++ ++/** ++ * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. ++ * @p: the task in question. ++ * @policy: new policy. ++ * @param: structure containing the new RT priority. ++ * ++ * Just like sched_setscheduler, only don't bother checking if the ++ * current context has permission. For example, this is needed in ++ * stop_machine(): we create temporary high priority worker threads, ++ * but our caller might not have that capability. ++ * ++ * Return: 0 on success. An error code otherwise. ++ */ ++int sched_setscheduler_nocheck(struct task_struct *p, int policy, ++ const struct sched_param *param) ++{ ++ return _sched_setscheduler(p, policy, param, false); ++} ++EXPORT_SYMBOL_GPL(sched_setscheduler_nocheck); ++ ++static int ++do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) ++{ ++ struct sched_param lparam; ++ struct task_struct *p; ++ int retval; ++ ++ if (!param || pid < 0) ++ return -EINVAL; ++ if (copy_from_user(&lparam, param, sizeof(struct sched_param))) ++ return -EFAULT; ++ ++ rcu_read_lock(); ++ retval = -ESRCH; ++ p = find_process_by_pid(pid); ++ if (p != NULL) ++ retval = sched_setscheduler(p, policy, &lparam); ++ rcu_read_unlock(); ++ ++ return retval; ++} ++ ++/* ++ * Mimics kernel/events/core.c perf_copy_attr(). ++ */ ++static int sched_copy_attr(struct sched_attr __user *uattr, ++ struct sched_attr *attr) ++{ ++ u32 size; ++ int ret; ++ ++ if (!access_ok(VERIFY_WRITE, uattr, SCHED_ATTR_SIZE_VER0)) ++ return -EFAULT; ++ ++ /* Zero the full structure, so that a short copy will be nice: */ ++ memset(attr, 0, sizeof(*attr)); ++ ++ ret = get_user(size, &uattr->size); ++ if (ret) ++ return ret; ++ ++ /* Bail out on silly large: */ ++ if (size > PAGE_SIZE) ++ goto err_size; ++ ++ /* ABI compatibility quirk: */ ++ if (!size) ++ size = SCHED_ATTR_SIZE_VER0; ++ ++ if (size < SCHED_ATTR_SIZE_VER0) ++ goto err_size; ++ ++ /* ++ * If we're handed a bigger struct than we know of, ++ * ensure all the unknown bits are 0 - i.e. new ++ * user-space does not rely on any kernel feature ++ * extensions we dont know about yet. ++ */ ++ if (size > sizeof(*attr)) { ++ unsigned char __user *addr; ++ unsigned char __user *end; ++ unsigned char val; ++ ++ addr = (void __user *)uattr + sizeof(*attr); ++ end = (void __user *)uattr + size; ++ ++ for (; addr < end; addr++) { ++ ret = get_user(val, addr); ++ if (ret) ++ return ret; ++ if (val) ++ goto err_size; ++ } ++ size = sizeof(*attr); ++ } ++ ++ ret = copy_from_user(attr, uattr, size); ++ if (ret) ++ return -EFAULT; ++ ++ /* ++ * XXX: Do we want to be lenient like existing syscalls; or do we want ++ * to be strict and return an error on out-of-bounds values? ++ */ ++ attr->sched_nice = clamp(attr->sched_nice, -20, 19); ++ ++ /* sched/core.c uses zero here but we already know ret is zero */ ++ return 0; ++ ++err_size: ++ put_user(sizeof(*attr), &uattr->size); ++ return -E2BIG; ++} ++ ++/* ++ * sched_setparam() passes in -1 for its policy, to let the functions ++ * it calls know not to change it. ++ */ ++#define SETPARAM_POLICY -1 ++ ++/** ++ * sys_sched_setscheduler - set/change the scheduler policy and RT priority ++ * @pid: the pid in question. ++ * @policy: new policy. ++ * @param: structure containing the new RT priority. ++ * ++ * Return: 0 on success. An error code otherwise. ++ */ ++SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, struct sched_param __user *, param) ++{ ++ if (policy < 0) ++ return -EINVAL; ++ ++ return do_sched_setscheduler(pid, policy, param); ++} ++ ++/** ++ * sys_sched_setparam - set/change the RT priority of a thread ++ * @pid: the pid in question. ++ * @param: structure containing the new RT priority. ++ * ++ * Return: 0 on success. An error code otherwise. ++ */ ++SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) ++{ ++ return do_sched_setscheduler(pid, SETPARAM_POLICY, param); ++} ++ ++/** ++ * sys_sched_setattr - same as above, but with extended sched_attr ++ * @pid: the pid in question. ++ * @uattr: structure containing the extended parameters. ++ */ ++SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr, ++ unsigned int, flags) ++{ ++ struct sched_attr attr; ++ struct task_struct *p; ++ int retval; ++ ++ if (!uattr || pid < 0 || flags) ++ return -EINVAL; ++ ++ retval = sched_copy_attr(uattr, &attr); ++ if (retval) ++ return retval; ++ ++ if ((int)attr.sched_policy < 0) ++ return -EINVAL; ++ ++ rcu_read_lock(); ++ retval = -ESRCH; ++ p = find_process_by_pid(pid); ++ if (p != NULL) ++ retval = sched_setattr(p, &attr); ++ rcu_read_unlock(); ++ ++ return retval; ++} ++ ++/** ++ * sys_sched_getscheduler - get the policy (scheduling class) of a thread ++ * @pid: the pid in question. ++ * ++ * Return: On success, the policy of the thread. Otherwise, a negative error ++ * code. ++ */ ++SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) ++{ ++ struct task_struct *p; ++ int retval = -EINVAL; ++ ++ if (pid < 0) ++ goto out_nounlock; ++ ++ retval = -ESRCH; ++ rcu_read_lock(); ++ p = find_process_by_pid(pid); ++ if (p) { ++ retval = security_task_getscheduler(p); ++ if (!retval) ++ retval = p->policy; ++ } ++ rcu_read_unlock(); ++ ++out_nounlock: ++ return retval; ++} ++ ++/** ++ * sys_sched_getscheduler - get the RT priority of a thread ++ * @pid: the pid in question. ++ * @param: structure containing the RT priority. ++ * ++ * Return: On success, 0 and the RT priority is in @param. Otherwise, an error ++ * code. ++ */ ++SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) ++{ ++ struct sched_param lp = { .sched_priority = 0 }; ++ struct task_struct *p; ++ int retval = -EINVAL; ++ ++ if (!param || pid < 0) ++ goto out_nounlock; ++ ++ rcu_read_lock(); ++ p = find_process_by_pid(pid); ++ retval = -ESRCH; ++ if (!p) ++ goto out_unlock; ++ ++ retval = security_task_getscheduler(p); ++ if (retval) ++ goto out_unlock; ++ ++ if (has_rt_policy(p)) ++ lp.sched_priority = p->rt_priority; ++ rcu_read_unlock(); ++ ++ /* ++ * This one might sleep, we cannot do it with a spinlock held ... ++ */ ++ retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; ++ ++out_nounlock: ++ return retval; ++ ++out_unlock: ++ rcu_read_unlock(); ++ return retval; ++} ++ ++static int sched_read_attr(struct sched_attr __user *uattr, ++ struct sched_attr *attr, ++ unsigned int usize) ++{ ++ int ret; ++ ++ if (!access_ok(VERIFY_WRITE, uattr, usize)) ++ return -EFAULT; ++ ++ /* ++ * If we're handed a smaller struct than we know of, ++ * ensure all the unknown bits are 0 - i.e. old ++ * user-space does not get uncomplete information. ++ */ ++ if (usize < sizeof(*attr)) { ++ unsigned char *addr; ++ unsigned char *end; ++ ++ addr = (void *)attr + usize; ++ end = (void *)attr + sizeof(*attr); ++ ++ for (; addr < end; addr++) { ++ if (*addr) ++ return -EFBIG; ++ } ++ ++ attr->size = usize; ++ } ++ ++ ret = copy_to_user(uattr, attr, attr->size); ++ if (ret) ++ return -EFAULT; ++ ++ /* sched/core.c uses zero here but we already know ret is zero */ ++ return ret; ++} ++ ++/** ++ * sys_sched_getattr - similar to sched_getparam, but with sched_attr ++ * @pid: the pid in question. ++ * @uattr: structure containing the extended parameters. ++ * @size: sizeof(attr) for fwd/bwd comp. ++ * @flags: for future extension. ++ */ ++SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, ++ unsigned int, size, unsigned int, flags) ++{ ++ struct sched_attr attr = { ++ .size = sizeof(struct sched_attr), ++ }; ++ struct task_struct *p; ++ int retval; ++ ++ if (!uattr || pid < 0 || size > PAGE_SIZE || ++ size < SCHED_ATTR_SIZE_VER0 || flags) ++ return -EINVAL; ++ ++ rcu_read_lock(); ++ p = find_process_by_pid(pid); ++ retval = -ESRCH; ++ if (!p) ++ goto out_unlock; ++ ++ retval = security_task_getscheduler(p); ++ if (retval) ++ goto out_unlock; ++ ++ attr.sched_policy = p->policy; ++ if (rt_task(p)) ++ attr.sched_priority = p->rt_priority; ++ else ++ attr.sched_nice = task_nice(p); ++ ++ rcu_read_unlock(); ++ ++ retval = sched_read_attr(uattr, &attr, size); ++ return retval; ++ ++out_unlock: ++ rcu_read_unlock(); ++ return retval; ++} ++ ++long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) ++{ ++ cpumask_var_t cpus_allowed, new_mask; ++ struct task_struct *p; ++ int retval; ++ ++ rcu_read_lock(); ++ ++ p = find_process_by_pid(pid); ++ if (!p) { ++ rcu_read_unlock(); ++ return -ESRCH; ++ } ++ ++ /* Prevent p going away */ ++ get_task_struct(p); ++ rcu_read_unlock(); ++ ++ if (p->flags & PF_NO_SETAFFINITY) { ++ retval = -EINVAL; ++ goto out_put_task; ++ } ++ if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { ++ retval = -ENOMEM; ++ goto out_put_task; ++ } ++ if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { ++ retval = -ENOMEM; ++ goto out_free_cpus_allowed; ++ } ++ retval = -EPERM; ++ if (!check_same_owner(p)) { ++ rcu_read_lock(); ++ if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) { ++ rcu_read_unlock(); ++ goto out_unlock; ++ } ++ rcu_read_unlock(); ++ } ++ ++ retval = security_task_setscheduler(p); ++ if (retval) ++ goto out_unlock; ++ ++ cpuset_cpus_allowed(p, cpus_allowed); ++ cpumask_and(new_mask, in_mask, cpus_allowed); ++again: ++ retval = __set_cpus_allowed_ptr(p, new_mask, true); ++ ++ if (!retval) { ++ cpuset_cpus_allowed(p, cpus_allowed); ++ if (!cpumask_subset(new_mask, cpus_allowed)) { ++ /* ++ * We must have raced with a concurrent cpuset ++ * update. Just reset the cpus_allowed to the ++ * cpuset's cpus_allowed ++ */ ++ cpumask_copy(new_mask, cpus_allowed); ++ goto again; ++ } ++ } ++out_unlock: ++ free_cpumask_var(new_mask); ++out_free_cpus_allowed: ++ free_cpumask_var(cpus_allowed); ++out_put_task: ++ put_task_struct(p); ++ return retval; ++} ++ ++static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, ++ cpumask_t *new_mask) ++{ ++ if (len < cpumask_size()) ++ cpumask_clear(new_mask); ++ else if (len > cpumask_size()) ++ len = cpumask_size(); ++ ++ return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; ++} ++ ++ ++/** ++ * sys_sched_setaffinity - set the CPU affinity of a process ++ * @pid: pid of the process ++ * @len: length in bytes of the bitmask pointed to by user_mask_ptr ++ * @user_mask_ptr: user-space pointer to the new CPU mask ++ * ++ * Return: 0 on success. An error code otherwise. ++ */ ++SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, ++ unsigned long __user *, user_mask_ptr) ++{ ++ cpumask_var_t new_mask; ++ int retval; ++ ++ if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) ++ return -ENOMEM; ++ ++ retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); ++ if (retval == 0) ++ retval = sched_setaffinity(pid, new_mask); ++ free_cpumask_var(new_mask); ++ return retval; ++} ++ ++long sched_getaffinity(pid_t pid, cpumask_t *mask) ++{ ++ struct task_struct *p; ++ unsigned long flags; ++ int retval; ++ ++ get_online_cpus(); ++ rcu_read_lock(); ++ ++ retval = -ESRCH; ++ p = find_process_by_pid(pid); ++ if (!p) ++ goto out_unlock; ++ ++ retval = security_task_getscheduler(p); ++ if (retval) ++ goto out_unlock; ++ ++ raw_spin_lock_irqsave(&p->pi_lock, flags); ++ cpumask_and(mask, &p->cpus_allowed, cpu_active_mask); ++ raw_spin_unlock_irqrestore(&p->pi_lock, flags); ++ ++out_unlock: ++ rcu_read_unlock(); ++ put_online_cpus(); ++ ++ return retval; ++} ++ ++/** ++ * sys_sched_getaffinity - get the CPU affinity of a process ++ * @pid: pid of the process ++ * @len: length in bytes of the bitmask pointed to by user_mask_ptr ++ * @user_mask_ptr: user-space pointer to hold the current CPU mask ++ * ++ * Return: 0 on success. An error code otherwise. ++ */ ++SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, ++ unsigned long __user *, user_mask_ptr) ++{ ++ int ret; ++ cpumask_var_t mask; ++ ++ if ((len * BITS_PER_BYTE) < nr_cpu_ids) ++ return -EINVAL; ++ if (len & (sizeof(unsigned long)-1)) ++ return -EINVAL; ++ ++ if (!alloc_cpumask_var(&mask, GFP_KERNEL)) ++ return -ENOMEM; ++ ++ ret = sched_getaffinity(pid, mask); ++ if (ret == 0) { ++ unsigned int retlen = min(len, cpumask_size()); ++ ++ if (copy_to_user(user_mask_ptr, mask, retlen)) ++ ret = -EFAULT; ++ else ++ ret = retlen; ++ } ++ free_cpumask_var(mask); ++ ++ return ret; ++} ++ ++/** ++ * sys_sched_yield - yield the current processor to other threads. ++ * ++ * This function yields the current CPU to other tasks. It does this by ++ * scheduling away the current task. If it still has the earliest deadline ++ * it will be scheduled again as the next task. ++ * ++ * Return: 0. ++ */ ++static void do_sched_yield(void) ++{ ++ struct rq *rq; ++ ++ if (!sched_yield_type) ++ return; ++ ++ local_irq_disable(); ++ rq = this_rq(); ++ rq_lock(rq); ++ ++ if (sched_yield_type > 1) ++ time_slice_expired(current, rq); ++ schedstat_inc(rq->yld_count); ++ ++ /* ++ * Since we are going to call schedule() anyway, there's ++ * no need to preempt or enable interrupts: ++ */ ++ preempt_disable(); ++ rq_unlock(rq); ++ sched_preempt_enable_no_resched(); ++ ++ schedule(); ++} ++ ++SYSCALL_DEFINE0(sched_yield) ++{ ++ do_sched_yield(); ++ return 0; ++} ++ ++#ifndef CONFIG_PREEMPT ++int __sched _cond_resched(void) ++{ ++ if (should_resched(0)) { ++ preempt_schedule_common(); ++ return 1; ++ } ++ rcu_all_qs(); ++ return 0; ++} ++EXPORT_SYMBOL(_cond_resched); ++#endif ++ ++/* ++ * __cond_resched_lock() - if a reschedule is pending, drop the given lock, ++ * call schedule, and on return reacquire the lock. ++ * ++ * This works OK both with and without CONFIG_PREEMPT. We do strange low-level ++ * operations here to prevent schedule() from being called twice (once via ++ * spin_unlock(), once by hand). ++ */ ++int __cond_resched_lock(spinlock_t *lock) ++{ ++ int resched = should_resched(PREEMPT_LOCK_OFFSET); ++ int ret = 0; ++ ++ lockdep_assert_held(lock); ++ ++ if (spin_needbreak(lock) || resched) { ++ spin_unlock(lock); ++ if (resched) ++ preempt_schedule_common(); ++ else ++ cpu_relax(); ++ ret = 1; ++ spin_lock(lock); ++ } ++ return ret; ++} ++EXPORT_SYMBOL(__cond_resched_lock); ++ ++/** ++ * yield - yield the current processor to other threads. ++ * ++ * Do not ever use this function, there's a 99% chance you're doing it wrong. ++ * ++ * The scheduler is at all times free to pick the calling task as the most ++ * eligible task to run, if removing the yield() call from your code breaks ++ * it, its already broken. ++ * ++ * Typical broken usage is: ++ * ++ * while (!event) ++ * yield(); ++ * ++ * where one assumes that yield() will let 'the other' process run that will ++ * make event true. If the current task is a SCHED_FIFO task that will never ++ * happen. Never use yield() as a progress guarantee!! ++ * ++ * If you want to use yield() to wait for something, use wait_event(). ++ * If you want to use yield() to be 'nice' for others, use cond_resched(). ++ * If you still want to use yield(), do not! ++ */ ++void __sched yield(void) ++{ ++ set_current_state(TASK_RUNNING); ++ do_sched_yield(); ++} ++EXPORT_SYMBOL(yield); ++ ++/** ++ * yield_to - yield the current processor to another thread in ++ * your thread group, or accelerate that thread toward the ++ * processor it's on. ++ * @p: target task ++ * @preempt: whether task preemption is allowed or not ++ * ++ * It's the caller's job to ensure that the target task struct ++ * can't go away on us before we can do any checks. ++ * ++ * Return: ++ * true (>0) if we indeed boosted the target task. ++ * false (0) if we failed to boost the target. ++ * -ESRCH if there's no task to yield to. ++ */ ++int __sched yield_to(struct task_struct *p, bool preempt) ++{ ++ struct task_struct *rq_p; ++ struct rq *rq, *p_rq; ++ unsigned long flags; ++ int yielded = 0; ++ ++ local_irq_save(flags); ++ rq = this_rq(); ++ ++again: ++ p_rq = task_rq(p); ++ /* ++ * If we're the only runnable task on the rq and target rq also ++ * has only one task, there's absolutely no point in yielding. ++ */ ++ if (task_running(p_rq, p) || p->state) { ++ yielded = -ESRCH; ++ goto out_irq; ++ } ++ ++ double_rq_lock(rq, p_rq); ++ if (unlikely(task_rq(p) != p_rq)) { ++ double_rq_unlock(rq, p_rq); ++ goto again; ++ } ++ ++ yielded = 1; ++ schedstat_inc(rq->yld_count); ++ rq_p = rq->curr; ++ if (p->deadline > rq_p->deadline) ++ p->deadline = rq_p->deadline; ++ p->time_slice += rq_p->time_slice; ++ if (p->time_slice > timeslice()) ++ p->time_slice = timeslice(); ++ time_slice_expired(rq_p, rq); ++ if (preempt && rq != p_rq) ++ resched_task(p_rq->curr); ++ double_rq_unlock(rq, p_rq); ++out_irq: ++ local_irq_restore(flags); ++ ++ if (yielded > 0) ++ schedule(); ++ return yielded; ++} ++EXPORT_SYMBOL_GPL(yield_to); ++ ++int io_schedule_prepare(void) ++{ ++ int old_iowait = current->in_iowait; ++ ++ current->in_iowait = 1; ++ blk_schedule_flush_plug(current); ++ ++ return old_iowait; ++} ++ ++void io_schedule_finish(int token) ++{ ++ current->in_iowait = token; ++} ++ ++/* ++ * This task is about to go to sleep on IO. Increment rq->nr_iowait so ++ * that process accounting knows that this is a task in IO wait state. ++ * ++ * But don't do that if it is a deliberate, throttling IO wait (this task ++ * has set its backing_dev_info: the queue against which it should throttle) ++ */ ++ ++long __sched io_schedule_timeout(long timeout) ++{ ++ int token; ++ long ret; ++ ++ token = io_schedule_prepare(); ++ ret = schedule_timeout(timeout); ++ io_schedule_finish(token); ++ ++ return ret; ++} ++EXPORT_SYMBOL(io_schedule_timeout); ++ ++void io_schedule(void) ++{ ++ int token; ++ ++ token = io_schedule_prepare(); ++ schedule(); ++ io_schedule_finish(token); ++} ++EXPORT_SYMBOL(io_schedule); ++ ++/** ++ * sys_sched_get_priority_max - return maximum RT priority. ++ * @policy: scheduling class. ++ * ++ * Return: On success, this syscall returns the maximum ++ * rt_priority that can be used by a given scheduling class. ++ * On failure, a negative error code is returned. ++ */ ++SYSCALL_DEFINE1(sched_get_priority_max, int, policy) ++{ ++ int ret = -EINVAL; ++ ++ switch (policy) { ++ case SCHED_FIFO: ++ case SCHED_RR: ++ ret = MAX_USER_RT_PRIO-1; ++ break; ++ case SCHED_NORMAL: ++ case SCHED_BATCH: ++ case SCHED_ISO: ++ case SCHED_IDLEPRIO: ++ ret = 0; ++ break; ++ } ++ return ret; ++} ++ ++/** ++ * sys_sched_get_priority_min - return minimum RT priority. ++ * @policy: scheduling class. ++ * ++ * Return: On success, this syscall returns the minimum ++ * rt_priority that can be used by a given scheduling class. ++ * On failure, a negative error code is returned. ++ */ ++SYSCALL_DEFINE1(sched_get_priority_min, int, policy) ++{ ++ int ret = -EINVAL; ++ ++ switch (policy) { ++ case SCHED_FIFO: ++ case SCHED_RR: ++ ret = 1; ++ break; ++ case SCHED_NORMAL: ++ case SCHED_BATCH: ++ case SCHED_ISO: ++ case SCHED_IDLEPRIO: ++ ret = 0; ++ break; ++ } ++ return ret; ++} ++ ++static int sched_rr_get_interval(pid_t pid, struct timespec64 *t) ++{ ++ struct task_struct *p; ++ unsigned int time_slice; ++ unsigned long flags; ++ struct rq *rq; ++ int retval; ++ ++ if (pid < 0) ++ return -EINVAL; ++ ++ retval = -ESRCH; ++ rcu_read_lock(); ++ p = find_process_by_pid(pid); ++ if (!p) ++ goto out_unlock; ++ ++ retval = security_task_getscheduler(p); ++ if (retval) ++ goto out_unlock; ++ ++ rq = task_rq_lock(p, &flags); ++ time_slice = p->policy == SCHED_FIFO ? 0 : MS_TO_NS(task_timeslice(p)); ++ task_rq_unlock(rq, p, &flags); ++ ++ rcu_read_unlock(); ++ *t = ns_to_timespec64(time_slice); ++ return 0; ++ ++out_unlock: ++ rcu_read_unlock(); ++ return retval; ++} ++ ++/** ++ * sys_sched_rr_get_interval - return the default timeslice of a process. ++ * @pid: pid of the process. ++ * @interval: userspace pointer to the timeslice value. ++ * ++ * this syscall writes the default timeslice value of a given process ++ * into the user-space timespec buffer. A value of '0' means infinity. ++ * ++ * Return: On success, 0 and the timeslice is in @interval. Otherwise, ++ * an error code. ++ */ ++SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, ++ struct timespec __user *, interval) ++{ ++ struct timespec64 t; ++ int retval = sched_rr_get_interval(pid, &t); ++ ++ if (retval == 0) ++ retval = put_timespec64(&t, interval); ++ ++ return retval; ++} ++ ++#ifdef CONFIG_COMPAT ++COMPAT_SYSCALL_DEFINE2(sched_rr_get_interval, ++ compat_pid_t, pid, ++ struct compat_timespec __user *, interval) ++{ ++ struct timespec64 t; ++ int retval = sched_rr_get_interval(pid, &t); ++ ++ if (retval == 0) ++ retval = compat_put_timespec64(&t, interval); ++ return retval; ++} ++#endif ++ ++void sched_show_task(struct task_struct *p) ++{ ++ unsigned long free = 0; ++ int ppid; ++ ++ if (!try_get_task_stack(p)) ++ return; ++ ++ printk(KERN_INFO "%-15.15s %c", p->comm, task_state_to_char(p)); ++ ++ if (p->state == TASK_RUNNING) ++ printk(KERN_CONT " running task "); ++#ifdef CONFIG_DEBUG_STACK_USAGE ++ free = stack_not_used(p); ++#endif ++ ppid = 0; ++ rcu_read_lock(); ++ if (pid_alive(p)) ++ ppid = task_pid_nr(rcu_dereference(p->real_parent)); ++ rcu_read_unlock(); ++ printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, ++ task_pid_nr(p), ppid, ++ (unsigned long)task_thread_info(p)->flags); ++ ++ print_worker_info(KERN_INFO, p); ++ show_stack(p, NULL); ++ put_task_stack(p); ++} ++EXPORT_SYMBOL_GPL(sched_show_task); ++ ++static inline bool ++state_filter_match(unsigned long state_filter, struct task_struct *p) ++{ ++ /* no filter, everything matches */ ++ if (!state_filter) ++ return true; ++ ++ /* filter, but doesn't match */ ++ if (!(p->state & state_filter)) ++ return false; ++ ++ /* ++ * When looking for TASK_UNINTERRUPTIBLE skip TASK_IDLE (allows ++ * TASK_KILLABLE). ++ */ ++ if (state_filter == TASK_UNINTERRUPTIBLE && p->state == TASK_IDLE) ++ return false; ++ ++ return true; ++} ++ ++void show_state_filter(unsigned long state_filter) ++{ ++ struct task_struct *g, *p; ++ ++#if BITS_PER_LONG == 32 ++ printk(KERN_INFO ++ " task PC stack pid father\n"); ++#else ++ printk(KERN_INFO ++ " task PC stack pid father\n"); ++#endif ++ rcu_read_lock(); ++ for_each_process_thread(g, p) { ++ /* ++ * reset the NMI-timeout, listing all files on a slow ++ * console might take a lot of time: ++ * Also, reset softlockup watchdogs on all CPUs, because ++ * another CPU might be blocked waiting for us to process ++ * an IPI. ++ */ ++ touch_nmi_watchdog(); ++ touch_all_softlockup_watchdogs(); ++ if (state_filter_match(state_filter, p)) ++ sched_show_task(p); ++ } ++ ++ rcu_read_unlock(); ++ /* ++ * Only show locks if all tasks are dumped: ++ */ ++ if (!state_filter) ++ debug_show_all_locks(); ++} ++ ++void dump_cpu_task(int cpu) ++{ ++ pr_info("Task dump for CPU %d:\n", cpu); ++ sched_show_task(cpu_curr(cpu)); ++} ++ ++#ifdef CONFIG_SMP ++void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask) ++{ ++ cpumask_copy(&p->cpus_allowed, new_mask); ++ p->nr_cpus_allowed = cpumask_weight(new_mask); ++} ++ ++void __do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) ++{ ++ struct rq *rq = task_rq(p); ++ ++ lockdep_assert_held(&p->pi_lock); ++ ++ cpumask_copy(&p->cpus_allowed, new_mask); ++ ++ if (task_queued(p)) { ++ /* ++ * Because __kthread_bind() calls this on blocked tasks without ++ * holding rq->lock. ++ */ ++ lockdep_assert_held(rq->lock); ++ } ++} ++ ++/* ++ * Calling do_set_cpus_allowed from outside the scheduler code should not be ++ * called on a running or queued task. We should be holding pi_lock. ++ */ ++void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) ++{ ++ __do_set_cpus_allowed(p, new_mask); ++ if (needs_other_cpu(p, task_cpu(p))) { ++ struct rq *rq; ++ ++ rq = __task_rq_lock(p); ++ set_task_cpu(p, valid_task_cpu(p)); ++ resched_task(p); ++ __task_rq_unlock(rq); ++ } ++} ++#endif ++ ++/** ++ * init_idle - set up an idle thread for a given CPU ++ * @idle: task in question ++ * @cpu: cpu the idle task belongs to ++ * ++ * NOTE: this function does not set the idle thread's NEED_RESCHED ++ * flag, to make booting more robust. ++ */ ++void init_idle(struct task_struct *idle, int cpu) ++{ ++ struct rq *rq = cpu_rq(cpu); ++ unsigned long flags; ++ ++ raw_spin_lock_irqsave(&idle->pi_lock, flags); ++ raw_spin_lock(rq->lock); ++ idle->last_ran = rq->niffies; ++ time_slice_expired(idle, rq); ++ idle->state = TASK_RUNNING; ++ /* Setting prio to illegal value shouldn't matter when never queued */ ++ idle->prio = PRIO_LIMIT; ++ ++ kasan_unpoison_task_stack(idle); ++ ++#ifdef CONFIG_SMP ++ /* ++ * It's possible that init_idle() gets called multiple times on a task, ++ * in that case do_set_cpus_allowed() will not do the right thing. ++ * ++ * And since this is boot we can forgo the serialisation. ++ */ ++ set_cpus_allowed_common(idle, cpumask_of(cpu)); ++#ifdef CONFIG_SMT_NICE ++ idle->smt_bias = 0; ++#endif ++#endif ++ set_rq_task(rq, idle); ++ ++ /* Silence PROVE_RCU */ ++ rcu_read_lock(); ++ set_task_cpu(idle, cpu); ++ rcu_read_unlock(); ++ ++ rq->curr = rq->idle = idle; ++ idle->on_rq = TASK_ON_RQ_QUEUED; ++ raw_spin_unlock(rq->lock); ++ raw_spin_unlock_irqrestore(&idle->pi_lock, flags); ++ ++ /* Set the preempt count _outside_ the spinlocks! */ ++ init_idle_preempt_count(idle, cpu); ++ ++ ftrace_graph_init_idle_task(idle, cpu); ++ vtime_init_idle(idle, cpu); ++#ifdef CONFIG_SMP ++ sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); ++#endif ++} ++ ++int cpuset_cpumask_can_shrink(const struct cpumask __maybe_unused *cur, ++ const struct cpumask __maybe_unused *trial) ++{ ++ return 1; ++} ++ ++int task_can_attach(struct task_struct *p, ++ const struct cpumask *cs_cpus_allowed) ++{ ++ int ret = 0; ++ ++ /* ++ * Kthreads which disallow setaffinity shouldn't be moved ++ * to a new cpuset; we don't want to change their CPU ++ * affinity and isolating such threads by their set of ++ * allowed nodes is unnecessary. Thus, cpusets are not ++ * applicable for such threads. This prevents checking for ++ * success of set_cpus_allowed_ptr() on all attached tasks ++ * before cpus_allowed may be changed. ++ */ ++ if (p->flags & PF_NO_SETAFFINITY) ++ ret = -EINVAL; ++ ++ return ret; ++} ++ ++void resched_cpu(int cpu) ++{ ++ struct rq *rq = cpu_rq(cpu); ++ unsigned long flags; ++ ++ rq_lock_irqsave(rq, &flags); ++ if (cpu_online(cpu) || cpu == smp_processor_id()) ++ resched_curr(rq); ++ rq_unlock_irqrestore(rq, &flags); ++} ++ ++#ifdef CONFIG_SMP ++#ifdef CONFIG_NO_HZ_COMMON ++void nohz_balance_enter_idle(int cpu) ++{ ++} ++ ++void select_nohz_load_balancer(int stop_tick) ++{ ++} ++ ++void set_cpu_sd_state_idle(void) {} ++ ++/* ++ * In the semi idle case, use the nearest busy CPU for migrating timers ++ * from an idle CPU. This is good for power-savings. ++ * ++ * We don't do similar optimization for completely idle system, as ++ * selecting an idle CPU will add more delays to the timers than intended ++ * (as that CPU's timer base may not be uptodate wrt jiffies etc). ++ */ ++int get_nohz_timer_target(void) ++{ ++ int i, cpu = smp_processor_id(); ++ struct sched_domain *sd; ++ ++ if (!idle_cpu(cpu) && housekeeping_cpu(cpu, HK_FLAG_TIMER)) ++ return cpu; ++ ++ rcu_read_lock(); ++ for_each_domain(cpu, sd) { ++ for_each_cpu(i, sched_domain_span(sd)) { ++ if (cpu == i) ++ continue; ++ ++ if (!idle_cpu(i) && housekeeping_cpu(i, HK_FLAG_TIMER)) { ++ cpu = i; ++ cpu = i; ++ goto unlock; ++ } ++ } ++ } ++ ++ if (!housekeeping_cpu(cpu, HK_FLAG_TIMER)) ++ cpu = housekeeping_any_cpu(HK_FLAG_TIMER); ++unlock: ++ rcu_read_unlock(); ++ return cpu; ++} ++ ++/* ++ * When add_timer_on() enqueues a timer into the timer wheel of an ++ * idle CPU then this timer might expire before the next timer event ++ * which is scheduled to wake up that CPU. In case of a completely ++ * idle system the next event might even be infinite time into the ++ * future. wake_up_idle_cpu() ensures that the CPU is woken up and ++ * leaves the inner idle loop so the newly added timer is taken into ++ * account when the CPU goes back to idle and evaluates the timer ++ * wheel for the next timer event. ++ */ ++void wake_up_idle_cpu(int cpu) ++{ ++ if (cpu == smp_processor_id()) ++ return; ++ ++ if (set_nr_and_not_polling(cpu_rq(cpu)->idle)) ++ smp_sched_reschedule(cpu); ++ else ++ trace_sched_wake_idle_without_ipi(cpu); ++} ++ ++static bool wake_up_full_nohz_cpu(int cpu) ++{ ++ /* ++ * We just need the target to call irq_exit() and re-evaluate ++ * the next tick. The nohz full kick at least implies that. ++ * If needed we can still optimize that later with an ++ * empty IRQ. ++ */ ++ if (cpu_is_offline(cpu)) ++ return true; /* Don't try to wake offline CPUs. */ ++ if (tick_nohz_full_cpu(cpu)) { ++ if (cpu != smp_processor_id() || ++ tick_nohz_tick_stopped()) ++ tick_nohz_full_kick_cpu(cpu); ++ return true; ++ } ++ ++ return false; ++} ++ ++/* ++ * Wake up the specified CPU. If the CPU is going offline, it is the ++ * caller's responsibility to deal with the lost wakeup, for example, ++ * by hooking into the CPU_DEAD notifier like timers and hrtimers do. ++ */ ++void wake_up_nohz_cpu(int cpu) ++{ ++ if (!wake_up_full_nohz_cpu(cpu)) ++ wake_up_idle_cpu(cpu); ++} ++#endif /* CONFIG_NO_HZ_COMMON */ ++ ++/* ++ * Change a given task's CPU affinity. Migrate the thread to a ++ * proper CPU and schedule it away if the CPU it's executing on ++ * is removed from the allowed bitmask. ++ * ++ * NOTE: the caller must have a valid reference to the task, the ++ * task must not exit() & deallocate itself prematurely. The ++ * call is not atomic; no spinlocks may be held. ++ */ ++static int __set_cpus_allowed_ptr(struct task_struct *p, ++ const struct cpumask *new_mask, bool check) ++{ ++ const struct cpumask *cpu_valid_mask = cpu_active_mask; ++ bool queued = false, running_wrong = false, kthread; ++ struct cpumask old_mask; ++ unsigned long flags; ++ int cpu, ret = 0; ++ struct rq *rq; ++ ++ rq = task_rq_lock(p, &flags); ++ update_rq_clock(rq); ++ ++ kthread = !!(p->flags & PF_KTHREAD); ++ if (kthread) { ++ /* ++ * Kernel threads are allowed on online && !active CPUs ++ */ ++ cpu_valid_mask = cpu_online_mask; ++ } ++ ++ /* ++ * Must re-check here, to close a race against __kthread_bind(), ++ * sched_setaffinity() is not guaranteed to observe the flag. ++ */ ++ if (check && (p->flags & PF_NO_SETAFFINITY)) { ++ ret = -EINVAL; ++ goto out; ++ } ++ ++ cpumask_copy(&old_mask, &p->cpus_allowed); ++ if (cpumask_equal(&old_mask, new_mask)) ++ goto out; ++ ++ if (!cpumask_intersects(new_mask, cpu_valid_mask)) { ++ ret = -EINVAL; ++ goto out; ++ } ++ ++ queued = task_queued(p); ++ __do_set_cpus_allowed(p, new_mask); ++ ++ if (kthread) { ++ /* ++ * For kernel threads that do indeed end up on online && ++ * !active we want to ensure they are strict per-CPU threads. ++ */ ++ WARN_ON(cpumask_intersects(new_mask, cpu_online_mask) && ++ !cpumask_intersects(new_mask, cpu_active_mask) && ++ p->nr_cpus_allowed != 1); ++ } ++ ++ /* Can the task run on the task's current CPU? If so, we're done */ ++ if (cpumask_test_cpu(task_cpu(p), new_mask)) ++ goto out; ++ ++ if (task_running(rq, p)) { ++ /* Task is running on the wrong cpu now, reschedule it. */ ++ if (rq == this_rq()) { ++ cpu = cpumask_any_and(cpu_valid_mask, new_mask); ++ set_task_cpu(p, cpu); ++ set_tsk_need_resched(p); ++ running_wrong = true; ++ } else ++ resched_task(p); ++ } else { ++ cpu = cpumask_any_and(cpu_valid_mask, new_mask); ++ if (queued) { ++ /* ++ * Switch runqueue locks after dequeueing the task ++ * here while still holding the pi_lock to be holding ++ * the correct lock for enqueueing. ++ */ ++ dequeue_task(rq, p, 0); ++ rq_unlock(rq); ++ ++ rq = cpu_rq(cpu); ++ rq_lock(rq); ++ } ++ set_task_cpu(p, cpu); ++ if (queued) ++ enqueue_task(rq, p, 0); ++ } ++ if (queued) ++ try_preempt(p, rq); ++ if (running_wrong) ++ preempt_disable(); ++out: ++ task_rq_unlock(rq, p, &flags); ++ ++ if (running_wrong) { ++ __schedule(true); ++ preempt_enable(); ++ } ++ ++ return ret; ++} ++ ++int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) ++{ ++ return __set_cpus_allowed_ptr(p, new_mask, false); ++} ++EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); ++ ++#ifdef CONFIG_HOTPLUG_CPU ++/* ++ * Run through task list and find tasks affined to the dead cpu, then remove ++ * that cpu from the list, enable cpu0 and set the zerobound flag. Must hold ++ * cpu 0 and src_cpu's runqueue locks. ++ */ ++static void bind_zero(int src_cpu) ++{ ++ struct task_struct *p, *t; ++ struct rq *rq0; ++ int bound = 0; ++ ++ if (src_cpu == 0) ++ return; ++ ++ rq0 = cpu_rq(0); ++ ++ do_each_thread(t, p) { ++ if (cpumask_test_cpu(src_cpu, &p->cpus_allowed)) { ++ bool local = (task_cpu(p) == src_cpu); ++ struct rq *rq = task_rq(p); ++ ++ /* task_running is the cpu stopper thread */ ++ if (local && task_running(rq, p)) ++ continue; ++ atomic_clear_cpu(src_cpu, &p->cpus_allowed); ++ atomic_set_cpu(0, &p->cpus_allowed); ++ p->zerobound = true; ++ bound++; ++ if (local) { ++ bool queued = task_queued(p); ++ ++ if (queued) ++ dequeue_task(rq, p, 0); ++ set_task_cpu(p, 0); ++ if (queued) ++ enqueue_task(rq0, p, 0); ++ } ++ } ++ } while_each_thread(t, p); ++ ++ if (bound) { ++ printk(KERN_INFO "Removed affinity for %d processes to cpu %d\n", ++ bound, src_cpu); ++ } ++} ++ ++/* Find processes with the zerobound flag and reenable their affinity for the ++ * CPU coming alive. */ ++static void unbind_zero(int src_cpu) ++{ ++ int unbound = 0, zerobound = 0; ++ struct task_struct *p, *t; ++ ++ if (src_cpu == 0) ++ return; ++ ++ do_each_thread(t, p) { ++ if (!p->mm) ++ p->zerobound = false; ++ if (p->zerobound) { ++ unbound++; ++ cpumask_set_cpu(src_cpu, &p->cpus_allowed); ++ /* Once every CPU affinity has been re-enabled, remove ++ * the zerobound flag */ ++ if (cpumask_subset(cpu_possible_mask, &p->cpus_allowed)) { ++ p->zerobound = false; ++ zerobound++; ++ } ++ } ++ } while_each_thread(t, p); ++ ++ if (unbound) { ++ printk(KERN_INFO "Added affinity for %d processes to cpu %d\n", ++ unbound, src_cpu); ++ } ++ if (zerobound) { ++ printk(KERN_INFO "Released forced binding to cpu0 for %d processes\n", ++ zerobound); ++ } ++} ++ ++/* ++ * Ensure that the idle task is using init_mm right before its cpu goes ++ * offline. ++ */ ++void idle_task_exit(void) ++{ ++ struct mm_struct *mm = current->active_mm; ++ ++ BUG_ON(cpu_online(smp_processor_id())); ++ ++ if (mm != &init_mm) { ++ switch_mm(mm, &init_mm, current); ++ current->active_mm = &init_mm; ++ finish_arch_post_lock_switch(); ++ } ++ mmdrop(mm); ++} ++#else /* CONFIG_HOTPLUG_CPU */ ++static void unbind_zero(int src_cpu) {} ++#endif /* CONFIG_HOTPLUG_CPU */ ++ ++void sched_set_stop_task(int cpu, struct task_struct *stop) ++{ ++ struct sched_param stop_param = { .sched_priority = STOP_PRIO }; ++ struct sched_param start_param = { .sched_priority = 0 }; ++ struct task_struct *old_stop = cpu_rq(cpu)->stop; ++ ++ if (stop) { ++ /* ++ * Make it appear like a SCHED_FIFO task, its something ++ * userspace knows about and won't get confused about. ++ * ++ * Also, it will make PI more or less work without too ++ * much confusion -- but then, stop work should not ++ * rely on PI working anyway. ++ */ ++ sched_setscheduler_nocheck(stop, SCHED_FIFO, &stop_param); ++ } ++ ++ cpu_rq(cpu)->stop = stop; ++ ++ if (old_stop) { ++ /* ++ * Reset it back to a normal scheduling policy so that ++ * it can die in pieces. ++ */ ++ sched_setscheduler_nocheck(old_stop, SCHED_NORMAL, &start_param); ++ } ++} ++ ++#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) ++ ++static struct ctl_table sd_ctl_dir[] = { ++ { ++ .procname = "sched_domain", ++ .mode = 0555, ++ }, ++ {} ++}; ++ ++static struct ctl_table sd_ctl_root[] = { ++ { ++ .procname = "kernel", ++ .mode = 0555, ++ .child = sd_ctl_dir, ++ }, ++ {} ++}; ++ ++static struct ctl_table *sd_alloc_ctl_entry(int n) ++{ ++ struct ctl_table *entry = ++ kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); ++ ++ return entry; ++} ++ ++static void sd_free_ctl_entry(struct ctl_table **tablep) ++{ ++ struct ctl_table *entry; ++ ++ /* ++ * In the intermediate directories, both the child directory and ++ * procname are dynamically allocated and could fail but the mode ++ * will always be set. In the lowest directory the names are ++ * static strings and all have proc handlers. ++ */ ++ for (entry = *tablep; entry->mode; entry++) { ++ if (entry->child) ++ sd_free_ctl_entry(&entry->child); ++ if (entry->proc_handler == NULL) ++ kfree(entry->procname); ++ } ++ ++ kfree(*tablep); ++ *tablep = NULL; ++} ++ ++#define CPU_LOAD_IDX_MAX 5 ++static int min_load_idx = 0; ++static int max_load_idx = CPU_LOAD_IDX_MAX-1; ++ ++static void ++set_table_entry(struct ctl_table *entry, ++ const char *procname, void *data, int maxlen, ++ umode_t mode, proc_handler *proc_handler, ++ bool load_idx) ++{ ++ entry->procname = procname; ++ entry->data = data; ++ entry->maxlen = maxlen; ++ entry->mode = mode; ++ entry->proc_handler = proc_handler; ++ ++ if (load_idx) { ++ entry->extra1 = &min_load_idx; ++ entry->extra2 = &max_load_idx; ++ } ++} ++ ++static struct ctl_table * ++sd_alloc_ctl_domain_table(struct sched_domain *sd) ++{ ++ struct ctl_table *table = sd_alloc_ctl_entry(14); ++ ++ if (table == NULL) ++ return NULL; ++ ++ set_table_entry(&table[0], "min_interval", &sd->min_interval, ++ sizeof(long), 0644, proc_doulongvec_minmax, false); ++ set_table_entry(&table[1], "max_interval", &sd->max_interval, ++ sizeof(long), 0644, proc_doulongvec_minmax, false); ++ set_table_entry(&table[2], "busy_idx", &sd->busy_idx, ++ sizeof(int), 0644, proc_dointvec_minmax, true); ++ set_table_entry(&table[3], "idle_idx", &sd->idle_idx, ++ sizeof(int), 0644, proc_dointvec_minmax, true); ++ set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, ++ sizeof(int), 0644, proc_dointvec_minmax, true); ++ set_table_entry(&table[5], "wake_idx", &sd->wake_idx, ++ sizeof(int), 0644, proc_dointvec_minmax, true); ++ set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, ++ sizeof(int), 0644, proc_dointvec_minmax, true); ++ set_table_entry(&table[7], "busy_factor", &sd->busy_factor, ++ sizeof(int), 0644, proc_dointvec_minmax, false); ++ set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, ++ sizeof(int), 0644, proc_dointvec_minmax, false); ++ set_table_entry(&table[9], "cache_nice_tries", ++ &sd->cache_nice_tries, ++ sizeof(int), 0644, proc_dointvec_minmax, false); ++ set_table_entry(&table[10], "flags", &sd->flags, ++ sizeof(int), 0644, proc_dointvec_minmax, false); ++ set_table_entry(&table[11], "max_newidle_lb_cost", ++ &sd->max_newidle_lb_cost, ++ sizeof(long), 0644, proc_doulongvec_minmax, false); ++ set_table_entry(&table[12], "name", sd->name, ++ CORENAME_MAX_SIZE, 0444, proc_dostring, false); ++ /* &table[13] is terminator */ ++ ++ return table; ++} ++ ++static struct ctl_table *sd_alloc_ctl_cpu_table(int cpu) ++{ ++ struct ctl_table *entry, *table; ++ struct sched_domain *sd; ++ int domain_num = 0, i; ++ char buf[32]; ++ ++ for_each_domain(cpu, sd) ++ domain_num++; ++ entry = table = sd_alloc_ctl_entry(domain_num + 1); ++ if (table == NULL) ++ return NULL; ++ ++ i = 0; ++ for_each_domain(cpu, sd) { ++ snprintf(buf, 32, "domain%d", i); ++ entry->procname = kstrdup(buf, GFP_KERNEL); ++ entry->mode = 0555; ++ entry->child = sd_alloc_ctl_domain_table(sd); ++ entry++; ++ i++; ++ } ++ return table; ++} ++ ++static cpumask_var_t sd_sysctl_cpus; ++static struct ctl_table_header *sd_sysctl_header; ++ ++void register_sched_domain_sysctl(void) ++{ ++ static struct ctl_table *cpu_entries; ++ static struct ctl_table **cpu_idx; ++ char buf[32]; ++ int i; ++ ++ if (!cpu_entries) { ++ cpu_entries = sd_alloc_ctl_entry(num_possible_cpus() + 1); ++ if (!cpu_entries) ++ return; ++ ++ WARN_ON(sd_ctl_dir[0].child); ++ sd_ctl_dir[0].child = cpu_entries; ++ } ++ ++ if (!cpu_idx) { ++ struct ctl_table *e = cpu_entries; ++ ++ cpu_idx = kcalloc(nr_cpu_ids, sizeof(struct ctl_table*), GFP_KERNEL); ++ if (!cpu_idx) ++ return; ++ ++ /* deal with sparse possible map */ ++ for_each_possible_cpu(i) { ++ cpu_idx[i] = e; ++ e++; ++ } ++ } ++ ++ if (!cpumask_available(sd_sysctl_cpus)) { ++ if (!alloc_cpumask_var(&sd_sysctl_cpus, GFP_KERNEL)) ++ return; ++ ++ /* init to possible to not have holes in @cpu_entries */ ++ cpumask_copy(sd_sysctl_cpus, cpu_possible_mask); ++ } ++ ++ for_each_cpu(i, sd_sysctl_cpus) { ++ struct ctl_table *e = cpu_idx[i]; ++ ++ if (e->child) ++ sd_free_ctl_entry(&e->child); ++ ++ if (!e->procname) { ++ snprintf(buf, 32, "cpu%d", i); ++ e->procname = kstrdup(buf, GFP_KERNEL); ++ } ++ e->mode = 0555; ++ e->child = sd_alloc_ctl_cpu_table(i); ++ ++ __cpumask_clear_cpu(i, sd_sysctl_cpus); ++ } ++ ++ WARN_ON(sd_sysctl_header); ++ sd_sysctl_header = register_sysctl_table(sd_ctl_root); ++} ++ ++void dirty_sched_domain_sysctl(int cpu) ++{ ++ if (cpumask_available(sd_sysctl_cpus)) ++ __cpumask_set_cpu(cpu, sd_sysctl_cpus); ++} ++ ++/* may be called multiple times per register */ ++void unregister_sched_domain_sysctl(void) ++{ ++ unregister_sysctl_table(sd_sysctl_header); ++ sd_sysctl_header = NULL; ++} ++#endif /* CONFIG_SYSCTL */ ++ ++void set_rq_online(struct rq *rq) ++{ ++ if (!rq->online) { ++ cpumask_set_cpu(cpu_of(rq), rq->rd->online); ++ rq->online = true; ++ } ++} ++ ++void set_rq_offline(struct rq *rq) ++{ ++ if (rq->online) { ++ int cpu = cpu_of(rq); ++ ++ cpumask_clear_cpu(cpu, rq->rd->online); ++ rq->online = false; ++ clear_cpuidle_map(cpu); ++ } ++} ++ ++/* ++ * used to mark begin/end of suspend/resume: ++ */ ++static int num_cpus_frozen; ++ ++/* ++ * Update cpusets according to cpu_active mask. If cpusets are ++ * disabled, cpuset_update_active_cpus() becomes a simple wrapper ++ * around partition_sched_domains(). ++ * ++ * If we come here as part of a suspend/resume, don't touch cpusets because we ++ * want to restore it back to its original state upon resume anyway. ++ */ ++static void cpuset_cpu_active(void) ++{ ++ if (cpuhp_tasks_frozen) { ++ /* ++ * num_cpus_frozen tracks how many CPUs are involved in suspend ++ * resume sequence. As long as this is not the last online ++ * operation in the resume sequence, just build a single sched ++ * domain, ignoring cpusets. ++ */ ++ partition_sched_domains(1, NULL, NULL); ++ if (--num_cpus_frozen) ++ return; ++ /* ++ * This is the last CPU online operation. So fall through and ++ * restore the original sched domains by considering the ++ * cpuset configurations. ++ */ ++ cpuset_force_rebuild(); ++ } ++ ++ cpuset_update_active_cpus(); ++} ++ ++static int cpuset_cpu_inactive(unsigned int cpu) ++{ ++ if (!cpuhp_tasks_frozen) { ++ cpuset_update_active_cpus(); ++ } else { ++ num_cpus_frozen++; ++ partition_sched_domains(1, NULL, NULL); ++ } ++ return 0; ++} ++ ++int sched_cpu_activate(unsigned int cpu) ++{ ++ struct rq *rq = cpu_rq(cpu); ++ unsigned long flags; ++ ++ set_cpu_active(cpu, true); ++ ++ if (sched_smp_initialized) { ++ sched_domains_numa_masks_set(cpu); ++ cpuset_cpu_active(); ++ } ++ ++ /* ++ * Put the rq online, if not already. This happens: ++ * ++ * 1) In the early boot process, because we build the real domains ++ * after all CPUs have been brought up. ++ * ++ * 2) At runtime, if cpuset_cpu_active() fails to rebuild the ++ * domains. ++ */ ++ rq_lock_irqsave(rq, &flags); ++ if (rq->rd) { ++ BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); ++ set_rq_online(rq); ++ } ++ unbind_zero(cpu); ++ rq_unlock_irqrestore(rq, &flags); ++ ++ return 0; ++} ++ ++int sched_cpu_deactivate(unsigned int cpu) ++{ ++ int ret; ++ ++ set_cpu_active(cpu, false); ++ /* ++ * We've cleared cpu_active_mask, wait for all preempt-disabled and RCU ++ * users of this state to go away such that all new such users will ++ * observe it. ++ * ++ * Do sync before park smpboot threads to take care the rcu boost case. ++ */ ++ synchronize_rcu_mult(call_rcu, call_rcu_sched); ++ ++ if (!sched_smp_initialized) ++ return 0; ++ ++ ret = cpuset_cpu_inactive(cpu); ++ if (ret) { ++ set_cpu_active(cpu, true); ++ return ret; ++ } ++ sched_domains_numa_masks_clear(cpu); ++ return 0; ++} ++ ++int sched_cpu_starting(unsigned int cpu) ++{ ++ sched_tick_start(cpu); ++ return 0; ++} ++ ++#ifdef CONFIG_HOTPLUG_CPU ++int sched_cpu_dying(unsigned int cpu) ++{ ++ struct rq *rq = cpu_rq(cpu); ++ unsigned long flags; ++ ++ /* Handle pending wakeups and then migrate everything off */ ++ sched_ttwu_pending(); ++ sched_tick_stop(cpu); ++ ++ local_irq_save(flags); ++ double_rq_lock(rq, cpu_rq(0)); ++ if (rq->rd) { ++ BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); ++ set_rq_offline(rq); ++ } ++ bind_zero(cpu); ++ double_rq_unlock(rq, cpu_rq(0)); ++ sched_start_tick(rq, cpu); ++ hrexpiry_clear(rq); ++ local_irq_restore(flags); ++ ++ return 0; ++} ++#endif ++ ++#if defined(CONFIG_SCHED_SMT) || defined(CONFIG_SCHED_MC) ++/* ++ * Cheaper version of the below functions in case support for SMT and MC is ++ * compiled in but CPUs have no siblings. ++ */ ++static bool sole_cpu_idle(struct rq *rq) ++{ ++ return rq_idle(rq); ++} ++#endif ++#ifdef CONFIG_SCHED_SMT ++static const cpumask_t *thread_cpumask(int cpu) ++{ ++ return topology_sibling_cpumask(cpu); ++} ++/* All this CPU's SMT siblings are idle */ ++static bool siblings_cpu_idle(struct rq *rq) ++{ ++ return cpumask_subset(&rq->thread_mask, &cpu_idle_map); ++} ++#endif ++#ifdef CONFIG_SCHED_MC ++static const cpumask_t *core_cpumask(int cpu) ++{ ++ return topology_core_cpumask(cpu); ++} ++/* All this CPU's shared cache siblings are idle */ ++static bool cache_cpu_idle(struct rq *rq) ++{ ++ return cpumask_subset(&rq->core_mask, &cpu_idle_map); ++} ++#endif ++ ++enum sched_domain_level { ++ SD_LV_NONE = 0, ++ SD_LV_SIBLING, ++ SD_LV_MC, ++ SD_LV_BOOK, ++ SD_LV_CPU, ++ SD_LV_NODE, ++ SD_LV_ALLNODES, ++ SD_LV_MAX ++}; ++ ++void __init sched_init_smp(void) ++{ ++ struct rq *rq, *other_rq, *leader; ++ struct sched_domain *sd; ++ int cpu, other_cpu, i; ++#ifdef CONFIG_SCHED_SMT ++ bool smt_threads = false; ++#endif ++ sched_init_numa(); ++ ++ /* ++ * There's no userspace yet to cause hotplug operations; hence all the ++ * cpu masks are stable and all blatant races in the below code cannot ++ * happen. ++ */ ++ mutex_lock(&sched_domains_mutex); ++ sched_init_domains(cpu_active_mask); ++ mutex_unlock(&sched_domains_mutex); ++ ++ /* Move init over to a non-isolated CPU */ ++ if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_FLAG_DOMAIN)) < 0) ++ BUG(); ++ ++ mutex_lock(&sched_domains_mutex); ++ local_irq_disable(); ++ lock_all_rqs(); ++ /* ++ * Set up the relative cache distance of each online cpu from each ++ * other in a simple array for quick lookup. Locality is determined ++ * by the closest sched_domain that CPUs are separated by. CPUs with ++ * shared cache in SMT and MC are treated as local. Separate CPUs ++ * (within the same package or physically) within the same node are ++ * treated as not local. CPUs not even in the same domain (different ++ * nodes) are treated as very distant. ++ */ ++ for_each_online_cpu(cpu) { ++ rq = cpu_rq(cpu); ++ ++ /* First check if this cpu is in the same node */ ++ for_each_domain(cpu, sd) { ++ if (sd->level > SD_LV_MC) ++ continue; ++ leader = NULL; ++ /* Set locality to local node if not already found lower */ ++ for_each_cpu(other_cpu, sched_domain_span(sd)) { ++ if (rqshare == RQSHARE_SMP) { ++ other_rq = cpu_rq(other_cpu); ++ ++ /* Set the smp_leader to the first CPU */ ++ if (!leader) ++ leader = rq; ++ other_rq->smp_leader = leader; ++ } ++ ++ if (rq->cpu_locality[other_cpu] > 3) ++ rq->cpu_locality[other_cpu] = 3; ++ } ++ } ++ ++ /* ++ * Each runqueue has its own function in case it doesn't have ++ * siblings of its own allowing mixed topologies. ++ */ ++#ifdef CONFIG_SCHED_MC ++ leader = NULL; ++ if (cpumask_weight(core_cpumask(cpu)) > 1) { ++ cpumask_copy(&rq->core_mask, core_cpumask(cpu)); ++ cpumask_clear_cpu(cpu, &rq->core_mask); ++ for_each_cpu(other_cpu, core_cpumask(cpu)) { ++ if (rqshare == RQSHARE_MC) { ++ other_rq = cpu_rq(other_cpu); ++ ++ /* Set the mc_leader to the first CPU */ ++ if (!leader) ++ leader = rq; ++ other_rq->mc_leader = leader; ++ } ++ if (rq->cpu_locality[other_cpu] > 2) ++ rq->cpu_locality[other_cpu] = 2; ++ } ++ rq->cache_idle = cache_cpu_idle; ++ } ++#endif ++#ifdef CONFIG_SCHED_SMT ++ leader = NULL; ++ if (cpumask_weight(thread_cpumask(cpu)) > 1) { ++ cpumask_copy(&rq->thread_mask, thread_cpumask(cpu)); ++ cpumask_clear_cpu(cpu, &rq->thread_mask); ++ for_each_cpu(other_cpu, thread_cpumask(cpu)) { ++ if (rqshare == RQSHARE_SMT) { ++ other_rq = cpu_rq(other_cpu); ++ ++ /* Set the smt_leader to the first CPU */ ++ if (!leader) ++ leader = rq; ++ other_rq->smt_leader = leader; ++ } ++ if (rq->cpu_locality[other_cpu] > 1) ++ rq->cpu_locality[other_cpu] = 1; ++ } ++ rq->siblings_idle = siblings_cpu_idle; ++ smt_threads = true; ++ } ++#endif ++ } ++ ++#ifdef CONFIG_SMT_NICE ++ if (smt_threads) { ++ check_siblings = &check_smt_siblings; ++ wake_siblings = &wake_smt_siblings; ++ smt_schedule = &smt_should_schedule; ++ } ++#endif ++ unlock_all_rqs(); ++ local_irq_enable(); ++ mutex_unlock(&sched_domains_mutex); ++ ++ for_each_online_cpu(cpu) { ++ rq = cpu_rq(cpu); ++ ++ for_each_online_cpu(other_cpu) { ++ if (other_cpu <= cpu) ++ continue; ++ printk(KERN_DEBUG "MuQSS locality CPU %d to %d: %d\n", cpu, other_cpu, rq->cpu_locality[other_cpu]); ++ } ++ } ++ ++ for_each_online_cpu(cpu) { ++ rq = cpu_rq(cpu); ++ leader = rq->smp_leader; ++ ++ rq_lock(rq); ++ if (leader && rq != leader) { ++ printk(KERN_INFO "Sharing SMP runqueue from CPU %d to CPU %d\n", ++ leader->cpu, rq->cpu); ++ kfree(rq->node); ++ kfree(rq->sl); ++ kfree(rq->lock); ++ rq->node = leader->node; ++ rq->sl = leader->sl; ++ rq->lock = leader->lock; ++ barrier(); ++ /* To make up for not unlocking the freed runlock */ ++ preempt_enable(); ++ } else ++ rq_unlock(rq); ++ } ++ ++#ifdef CONFIG_SCHED_MC ++ for_each_online_cpu(cpu) { ++ rq = cpu_rq(cpu); ++ leader = rq->mc_leader; ++ ++ rq_lock(rq); ++ if (leader && rq != leader) { ++ printk(KERN_INFO "Sharing MC runqueue from CPU %d to CPU %d\n", ++ leader->cpu, rq->cpu); ++ kfree(rq->node); ++ kfree(rq->sl); ++ kfree(rq->lock); ++ rq->node = leader->node; ++ rq->sl = leader->sl; ++ rq->lock = leader->lock; ++ barrier(); ++ /* To make up for not unlocking the freed runlock */ ++ preempt_enable(); ++ } else ++ rq_unlock(rq); ++ } ++#endif /* CONFIG_SCHED_MC */ ++ ++#ifdef CONFIG_SCHED_SMT ++ for_each_online_cpu(cpu) { ++ rq = cpu_rq(cpu); ++ ++ leader = rq->smt_leader; ++ ++ rq_lock(rq); ++ if (leader && rq != leader) { ++ printk(KERN_INFO "Sharing SMT runqueue from CPU %d to CPU %d\n", ++ leader->cpu, rq->cpu); ++ kfree(rq->node); ++ kfree(rq->sl); ++ kfree(rq->lock); ++ rq->node = leader->node; ++ rq->sl = leader->sl; ++ rq->lock = leader->lock; ++ barrier(); ++ /* To make up for not unlocking the freed runlock */ ++ preempt_enable(); ++ } else ++ rq_unlock(rq); ++ } ++#endif /* CONFIG_SCHED_SMT */ ++ ++ total_runqueues = 0; ++ for_each_possible_cpu(cpu) { ++ int locality, total_rqs = 0, total_cpus = 0; ++ ++ rq = cpu_rq(cpu); ++ if ( ++#ifdef CONFIG_SCHED_MC ++ (rq->mc_leader == rq) && ++#endif ++#ifdef CONFIG_SCHED_SMT ++ (rq->smt_leader == rq) && ++#endif ++ (rq->smp_leader == rq)) ++ total_runqueues++; ++ ++ for (locality = 0; locality <= 4; locality++) { ++ int test_cpu; ++ ++ for_each_possible_cpu(test_cpu) { ++ /* Work from each CPU up instead of every rq ++ * starting at CPU 0 */ ++ other_cpu = test_cpu + cpu; ++ other_cpu %= num_possible_cpus(); ++ other_rq = cpu_rq(other_cpu); ++ ++ if (rq->cpu_locality[other_cpu] == locality) { ++ rq->cpu_order[total_cpus++] = other_rq; ++ if ( ++ ++#ifdef CONFIG_SCHED_MC ++ (other_rq->mc_leader == other_rq) && ++#endif ++#ifdef CONFIG_SCHED_SMT ++ (other_rq->smt_leader == other_rq) && ++#endif ++ (other_rq->smp_leader == other_rq)) ++ rq->rq_order[total_rqs++] = other_rq; ++ } ++ } ++ } ++ } ++ ++ for_each_possible_cpu(cpu) { ++ rq = cpu_rq(cpu); ++ for (i = 0; i < total_runqueues; i++) { ++ printk(KERN_DEBUG "CPU %d RQ order %d RQ %d\n", cpu, i, ++ rq->rq_order[i]->cpu); ++ } ++ } ++ for_each_possible_cpu(cpu) { ++ rq = cpu_rq(cpu); ++ for (i = 0; i < num_possible_cpus(); i++) { ++ printk(KERN_DEBUG "CPU %d CPU order %d RQ %d\n", cpu, i, ++ rq->cpu_order[i]->cpu); ++ } ++ } ++ switch (rqshare) { ++ case RQSHARE_SMP: ++ printk(KERN_INFO "MuQSS runqueue share type SMP total runqueues: %d\n", ++ total_runqueues); ++ break; ++ case RQSHARE_MC: ++ printk(KERN_INFO "MuQSS runqueue share type MC total runqueues: %d\n", ++ total_runqueues); ++ break; ++ case RQSHARE_SMT: ++ printk(KERN_INFO "MuQSS runqueue share type SMT total runqueues: %d\n", ++ total_runqueues); ++ break; ++ case RQSHARE_NONE: ++ printk(KERN_INFO "MuQSS runqueue share type none total runqueues: %d\n", ++ total_runqueues); ++ break; ++ } ++ ++ sched_smp_initialized = true; ++} ++#else ++void __init sched_init_smp(void) ++{ ++ sched_smp_initialized = true; ++} ++#endif /* CONFIG_SMP */ ++ ++int in_sched_functions(unsigned long addr) ++{ ++ return in_lock_functions(addr) || ++ (addr >= (unsigned long)__sched_text_start ++ && addr < (unsigned long)__sched_text_end); ++} ++ ++#ifdef CONFIG_CGROUP_SCHED ++/* task group related information */ ++struct task_group { ++ struct cgroup_subsys_state css; ++ ++ struct rcu_head rcu; ++ struct list_head list; ++ ++ struct task_group *parent; ++ struct list_head siblings; ++ struct list_head children; ++}; ++ ++/* ++ * Default task group. ++ * Every task in system belongs to this group at bootup. ++ */ ++struct task_group root_task_group; ++LIST_HEAD(task_groups); ++ ++/* Cacheline aligned slab cache for task_group */ ++static struct kmem_cache *task_group_cache __read_mostly; ++#endif /* CONFIG_CGROUP_SCHED */ ++ ++void __init sched_init(void) ++{ ++#ifdef CONFIG_SMP ++ int cpu_ids; ++#endif ++ int i; ++ struct rq *rq; ++ ++ wait_bit_init(); ++ ++ prio_ratios[0] = 128; ++ for (i = 1 ; i < NICE_WIDTH ; i++) ++ prio_ratios[i] = prio_ratios[i - 1] * 11 / 10; ++ ++ skiplist_node_init(&init_task.node); ++ ++#ifdef CONFIG_SMP ++ init_defrootdomain(); ++ cpumask_clear(&cpu_idle_map); ++#else ++ uprq = &per_cpu(runqueues, 0); ++#endif ++ ++#ifdef CONFIG_CGROUP_SCHED ++ task_group_cache = KMEM_CACHE(task_group, 0); ++ ++ list_add(&root_task_group.list, &task_groups); ++ INIT_LIST_HEAD(&root_task_group.children); ++ INIT_LIST_HEAD(&root_task_group.siblings); ++#endif /* CONFIG_CGROUP_SCHED */ ++ for_each_possible_cpu(i) { ++ rq = cpu_rq(i); ++ rq->node = kmalloc(sizeof(skiplist_node), GFP_ATOMIC); ++ skiplist_init(rq->node); ++ rq->sl = new_skiplist(rq->node); ++ rq->lock = kmalloc(sizeof(raw_spinlock_t), GFP_ATOMIC); ++ raw_spin_lock_init(rq->lock); ++ rq->nr_running = 0; ++ rq->nr_uninterruptible = 0; ++ rq->nr_switches = 0; ++ rq->clock = rq->old_clock = rq->last_niffy = rq->niffies = 0; ++ rq->last_jiffy = jiffies; ++ rq->user_ns = rq->nice_ns = rq->softirq_ns = rq->system_ns = ++ rq->iowait_ns = rq->idle_ns = 0; ++ rq->dither = 0; ++ set_rq_task(rq, &init_task); ++ rq->iso_ticks = 0; ++ rq->iso_refractory = false; ++#ifdef CONFIG_SMP ++ rq->smp_leader = rq; ++#ifdef CONFIG_SCHED_MC ++ rq->mc_leader = rq; ++#endif ++#ifdef CONFIG_SCHED_SMT ++ rq->smt_leader = rq; ++#endif ++ rq->sd = NULL; ++ rq->rd = NULL; ++ rq->online = false; ++ rq->cpu = i; ++ rq_attach_root(rq, &def_root_domain); ++#endif ++ init_rq_hrexpiry(rq); ++ atomic_set(&rq->nr_iowait, 0); ++ } ++ ++#ifdef CONFIG_SMP ++ cpu_ids = i; ++ /* ++ * Set the base locality for cpu cache distance calculation to ++ * "distant" (3). Make sure the distance from a CPU to itself is 0. ++ */ ++ for_each_possible_cpu(i) { ++ int j; ++ ++ rq = cpu_rq(i); ++#ifdef CONFIG_SCHED_SMT ++ rq->siblings_idle = sole_cpu_idle; ++#endif ++#ifdef CONFIG_SCHED_MC ++ rq->cache_idle = sole_cpu_idle; ++#endif ++ rq->cpu_locality = kmalloc(cpu_ids * sizeof(int *), GFP_ATOMIC); ++ for_each_possible_cpu(j) { ++ if (i == j) ++ rq->cpu_locality[j] = 0; ++ else ++ rq->cpu_locality[j] = 4; ++ } ++ rq->rq_order = kmalloc(cpu_ids * sizeof(struct rq *), GFP_ATOMIC); ++ rq->cpu_order = kmalloc(cpu_ids * sizeof(struct rq *), GFP_ATOMIC); ++ rq->rq_order[0] = rq->cpu_order[0] = rq; ++ for (j = 1; j < cpu_ids; j++) ++ rq->rq_order[j] = rq->cpu_order[j] = cpu_rq(j); ++ } ++#endif ++ ++ /* ++ * The boot idle thread does lazy MMU switching as well: ++ */ ++ mmgrab(&init_mm); ++ enter_lazy_tlb(&init_mm, current); ++ ++ /* ++ * Make us the idle thread. Technically, schedule() should not be ++ * called from this thread, however somewhere below it might be, ++ * but because we are the idle thread, we just pick up running again ++ * when this runqueue becomes "idle". ++ */ ++ init_idle(current, smp_processor_id()); ++ ++#ifdef CONFIG_SMP ++ idle_thread_set_boot_cpu(); ++#endif /* SMP */ ++ ++ init_schedstats(); ++} ++ ++#ifdef CONFIG_DEBUG_ATOMIC_SLEEP ++static inline int preempt_count_equals(int preempt_offset) ++{ ++ int nested = preempt_count() + rcu_preempt_depth(); ++ ++ return (nested == preempt_offset); ++} ++ ++void __might_sleep(const char *file, int line, int preempt_offset) ++{ ++ /* ++ * Blocking primitives will set (and therefore destroy) current->state, ++ * since we will exit with TASK_RUNNING make sure we enter with it, ++ * otherwise we will destroy state. ++ */ ++ WARN_ONCE(current->state != TASK_RUNNING && current->task_state_change, ++ "do not call blocking ops when !TASK_RUNNING; " ++ "state=%lx set at [<%p>] %pS\n", ++ current->state, ++ (void *)current->task_state_change, ++ (void *)current->task_state_change); ++ ++ ___might_sleep(file, line, preempt_offset); ++} ++EXPORT_SYMBOL(__might_sleep); ++ ++void ___might_sleep(const char *file, int line, int preempt_offset) ++{ ++ /* Ratelimiting timestamp: */ ++ static unsigned long prev_jiffy; ++ ++ unsigned long preempt_disable_ip; ++ ++ /* WARN_ON_ONCE() by default, no rate limit required: */ ++ rcu_sleep_check(); ++ ++ if ((preempt_count_equals(preempt_offset) && !irqs_disabled() && ++ !is_idle_task(current)) || ++ system_state == SYSTEM_BOOTING || system_state > SYSTEM_RUNNING || ++ oops_in_progress) ++ return; ++ ++ if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) ++ return; ++ prev_jiffy = jiffies; ++ ++ /* Save this before calling printk(), since that will clobber it: */ ++ preempt_disable_ip = get_preempt_disable_ip(current); ++ ++ printk(KERN_ERR ++ "BUG: sleeping function called from invalid context at %s:%d\n", ++ file, line); ++ printk(KERN_ERR ++ "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", ++ in_atomic(), irqs_disabled(), ++ current->pid, current->comm); ++ ++ if (task_stack_end_corrupted(current)) ++ printk(KERN_EMERG "Thread overran stack, or stack corrupted\n"); ++ ++ debug_show_held_locks(current); ++ if (irqs_disabled()) ++ print_irqtrace_events(current); ++ if (IS_ENABLED(CONFIG_DEBUG_PREEMPT) ++ && !preempt_count_equals(preempt_offset)) { ++ pr_err("Preemption disabled at:"); ++ print_ip_sym(preempt_disable_ip); ++ pr_cont("\n"); ++ } ++ dump_stack(); ++ add_taint(TAINT_WARN, LOCKDEP_STILL_OK); ++} ++EXPORT_SYMBOL(___might_sleep); ++#endif ++ ++#ifdef CONFIG_MAGIC_SYSRQ ++static inline void normalise_rt_tasks(void) ++{ ++ struct task_struct *g, *p; ++ unsigned long flags; ++ struct rq *rq; ++ ++ read_lock(&tasklist_lock); ++ for_each_process_thread(g, p) { ++ /* ++ * Only normalize user tasks: ++ */ ++ if (p->flags & PF_KTHREAD) ++ continue; ++ ++ if (!rt_task(p) && !iso_task(p)) ++ continue; ++ ++ rq = task_rq_lock(p, &flags); ++ __setscheduler(p, rq, SCHED_NORMAL, 0, false); ++ task_rq_unlock(rq, p, &flags); ++ } ++ read_unlock(&tasklist_lock); ++} ++ ++void normalize_rt_tasks(void) ++{ ++ normalise_rt_tasks(); ++} ++#endif /* CONFIG_MAGIC_SYSRQ */ ++ ++#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) ++/* ++ * These functions are only useful for the IA64 MCA handling, or kdb. ++ * ++ * They can only be called when the whole system has been ++ * stopped - every CPU needs to be quiescent, and no scheduling ++ * activity can take place. Using them for anything else would ++ * be a serious bug, and as a result, they aren't even visible ++ * under any other configuration. ++ */ ++ ++/** ++ * curr_task - return the current task for a given CPU. ++ * @cpu: the processor in question. ++ * ++ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! ++ * ++ * Return: The current task for @cpu. ++ */ ++struct task_struct *curr_task(int cpu) ++{ ++ return cpu_curr(cpu); ++} ++ ++#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ ++ ++#ifdef CONFIG_IA64 ++/** ++ * set_curr_task - set the current task for a given CPU. ++ * @cpu: the processor in question. ++ * @p: the task pointer to set. ++ * ++ * Description: This function must only be used when non-maskable interrupts ++ * are serviced on a separate stack. It allows the architecture to switch the ++ * notion of the current task on a CPU in a non-blocking manner. This function ++ * must be called with all CPU's synchronised, and interrupts disabled, the ++ * and caller must save the original value of the current task (see ++ * curr_task() above) and restore that value before reenabling interrupts and ++ * re-starting the system. ++ * ++ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! ++ */ ++void ia64_set_curr_task(int cpu, struct task_struct *p) ++{ ++ cpu_curr(cpu) = p; ++} ++ ++#endif ++ ++void init_idle_bootup_task(struct task_struct *idle) ++{} ++ ++#ifdef CONFIG_SCHED_DEBUG ++__read_mostly bool sched_debug_enabled; ++ ++void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns, ++ struct seq_file *m) ++{} ++ ++void proc_sched_set_task(struct task_struct *p) ++{} ++#endif ++ ++#ifdef CONFIG_SMP ++#define SCHED_LOAD_SHIFT (10) ++#define SCHED_LOAD_SCALE (1L << SCHED_LOAD_SHIFT) ++ ++unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu) ++{ ++ return SCHED_LOAD_SCALE; ++} ++ ++unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu) ++{ ++ unsigned long weight = cpumask_weight(sched_domain_span(sd)); ++ unsigned long smt_gain = sd->smt_gain; ++ ++ smt_gain /= weight; ++ ++ return smt_gain; ++} ++#endif ++ ++#ifdef CONFIG_CGROUP_SCHED ++static void sched_free_group(struct task_group *tg) ++{ ++ kmem_cache_free(task_group_cache, tg); ++} ++ ++/* allocate runqueue etc for a new task group */ ++struct task_group *sched_create_group(struct task_group *parent) ++{ ++ struct task_group *tg; ++ ++ tg = kmem_cache_alloc(task_group_cache, GFP_KERNEL | __GFP_ZERO); ++ if (!tg) ++ return ERR_PTR(-ENOMEM); ++ ++ return tg; ++} ++ ++void sched_online_group(struct task_group *tg, struct task_group *parent) ++{ ++} ++ ++/* rcu callback to free various structures associated with a task group */ ++static void sched_free_group_rcu(struct rcu_head *rhp) ++{ ++ /* Now it should be safe to free those cfs_rqs */ ++ sched_free_group(container_of(rhp, struct task_group, rcu)); ++} ++ ++void sched_destroy_group(struct task_group *tg) ++{ ++ /* Wait for possible concurrent references to cfs_rqs complete */ ++ call_rcu(&tg->rcu, sched_free_group_rcu); ++} ++ ++void sched_offline_group(struct task_group *tg) ++{ ++} ++ ++static inline struct task_group *css_tg(struct cgroup_subsys_state *css) ++{ ++ return css ? container_of(css, struct task_group, css) : NULL; ++} ++ ++static struct cgroup_subsys_state * ++cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) ++{ ++ struct task_group *parent = css_tg(parent_css); ++ struct task_group *tg; ++ ++ if (!parent) { ++ /* This is early initialization for the top cgroup */ ++ return &root_task_group.css; ++ } ++ ++ tg = sched_create_group(parent); ++ if (IS_ERR(tg)) ++ return ERR_PTR(-ENOMEM); ++ return &tg->css; ++} ++ ++/* Expose task group only after completing cgroup initialization */ ++static int cpu_cgroup_css_online(struct cgroup_subsys_state *css) ++{ ++ struct task_group *tg = css_tg(css); ++ struct task_group *parent = css_tg(css->parent); ++ ++ if (parent) ++ sched_online_group(tg, parent); ++ return 0; ++} ++ ++static void cpu_cgroup_css_released(struct cgroup_subsys_state *css) ++{ ++ struct task_group *tg = css_tg(css); ++ ++ sched_offline_group(tg); ++} ++ ++static void cpu_cgroup_css_free(struct cgroup_subsys_state *css) ++{ ++ struct task_group *tg = css_tg(css); ++ ++ /* ++ * Relies on the RCU grace period between css_released() and this. ++ */ ++ sched_free_group(tg); ++} ++ ++static void cpu_cgroup_fork(struct task_struct *task) ++{ ++} ++ ++static int cpu_cgroup_can_attach(struct cgroup_taskset *tset) ++{ ++ return 0; ++} ++ ++static void cpu_cgroup_attach(struct cgroup_taskset *tset) ++{ ++} ++ ++static struct cftype cpu_legacy_files[] = { ++ { } /* Terminate */ ++}; ++ ++static struct cftype cpu_files[] = { ++ { } /* terminate */ ++}; ++ ++static int cpu_extra_stat_show(struct seq_file *sf, ++ struct cgroup_subsys_state *css) ++{ ++ return 0; ++} ++ ++struct cgroup_subsys cpu_cgrp_subsys = { ++ .css_alloc = cpu_cgroup_css_alloc, ++ .css_online = cpu_cgroup_css_online, ++ .css_released = cpu_cgroup_css_released, ++ .css_free = cpu_cgroup_css_free, ++ .css_extra_stat_show = cpu_extra_stat_show, ++ .fork = cpu_cgroup_fork, ++ .can_attach = cpu_cgroup_can_attach, ++ .attach = cpu_cgroup_attach, ++ .legacy_cftypes = cpu_files, ++ .legacy_cftypes = cpu_legacy_files, ++ .dfl_cftypes = cpu_files, ++ .early_init = true, ++ .threaded = true, ++}; ++#endif /* CONFIG_CGROUP_SCHED */ ++ ++#undef CREATE_TRACE_POINTS +diff -Nur a/kernel/sched/MuQSS.h b/kernel/sched/MuQSS.h +--- a/kernel/sched/MuQSS.h 1970-01-01 01:00:00.000000000 +0100 ++++ b/kernel/sched/MuQSS.h 2019-02-09 17:46:12.001297867 +0000 +@@ -0,0 +1,881 @@ ++/* SPDX-License-Identifier: GPL-2.0 */ ++#ifndef MUQSS_SCHED_H ++#define MUQSS_SCHED_H ++ ++#include <linux/sched/clock.h> ++#include <linux/sched/wake_q.h> ++#include <linux/sched/signal.h> ++#include <linux/sched/mm.h> ++#include <linux/sched/cpufreq.h> ++#include <linux/sched/stat.h> ++#include <linux/sched/nohz.h> ++#include <linux/sched/debug.h> ++#include <linux/sched/hotplug.h> ++#include <linux/sched/task.h> ++#include <linux/sched/task_stack.h> ++#include <linux/sched/topology.h> ++#include <linux/sched/cputime.h> ++#include <linux/sched/init.h> ++#include <linux/sched/isolation.h> ++ ++#include <uapi/linux/sched/types.h> ++ ++#include <linux/cgroup.h> ++#include <linux/cpufreq.h> ++#include <linux/cpuidle.h> ++#include <linux/ctype.h> ++#include <linux/freezer.h> ++#include <linux/interrupt.h> ++#include <linux/kernel_stat.h> ++#include <linux/kthread.h> ++#include <linux/livepatch.h> ++#include <linux/proc_fs.h> ++#include <linux/sched.h> ++#include <linux/slab.h> ++#include <linux/skip_list.h> ++#include <linux/stackprotector.h> ++#include <linux/stop_machine.h> ++#include <linux/suspend.h> ++#include <linux/swait.h> ++#include <linux/tick.h> ++#include <linux/tsacct_kern.h> ++#include <linux/u64_stats_sync.h> ++ ++#ifdef CONFIG_PARAVIRT ++#include <asm/paravirt.h> ++#endif ++ ++#include "cpupri.h" ++ ++#ifdef CONFIG_SCHED_DEBUG ++# define SCHED_WARN_ON(x) WARN_ONCE(x, #x) ++#else ++# define SCHED_WARN_ON(x) ((void)(x)) ++#endif ++ ++/* task_struct::on_rq states: */ ++#define TASK_ON_RQ_QUEUED 1 ++#define TASK_ON_RQ_MIGRATING 2 ++ ++struct rq; ++ ++#if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) ++#define HAVE_SCHED_AVG_IRQ ++#endif ++ ++#ifdef CONFIG_SMP ++ ++static inline bool sched_asym_prefer(int a, int b) ++{ ++ return arch_asym_cpu_priority(a) > arch_asym_cpu_priority(b); ++} ++ ++/* ++ * We add the notion of a root-domain which will be used to define per-domain ++ * variables. Each exclusive cpuset essentially defines an island domain by ++ * fully partitioning the member cpus from any other cpuset. Whenever a new ++ * exclusive cpuset is created, we also create and attach a new root-domain ++ * object. ++ * ++ */ ++struct root_domain { ++ atomic_t refcount; ++ atomic_t rto_count; ++ struct rcu_head rcu; ++ cpumask_var_t span; ++ cpumask_var_t online; ++ ++ /* Indicate more than one runnable task for any CPU */ ++ bool overload; ++ ++ /* ++ * The bit corresponding to a CPU gets set here if such CPU has more ++ * than one runnable -deadline task (as it is below for RT tasks). ++ */ ++ cpumask_var_t dlo_mask; ++ atomic_t dlo_count; ++ /* Replace unused CFS structures with void */ ++ //struct dl_bw dl_bw; ++ //struct cpudl cpudl; ++ void *dl_bw; ++ void *cpudl; ++ ++ /* ++ * The "RT overload" flag: it gets set if a CPU has more than ++ * one runnable RT task. ++ */ ++ cpumask_var_t rto_mask; ++ //struct cpupri cpupri; ++ void *cpupri; ++ ++ unsigned long max_cpu_capacity; ++}; ++ ++extern struct root_domain def_root_domain; ++extern struct mutex sched_domains_mutex; ++ ++extern void init_defrootdomain(void); ++extern int sched_init_domains(const struct cpumask *cpu_map); ++extern void rq_attach_root(struct rq *rq, struct root_domain *rd); ++ ++static inline void cpupri_cleanup(void __maybe_unused *cpupri) ++{ ++} ++ ++static inline void cpudl_cleanup(void __maybe_unused *cpudl) ++{ ++} ++ ++static inline void init_dl_bw(void __maybe_unused *dl_bw) ++{ ++} ++ ++static inline int cpudl_init(void __maybe_unused *dl_bw) ++{ ++ return 0; ++} ++ ++static inline int cpupri_init(void __maybe_unused *cpupri) ++{ ++ return 0; ++} ++#endif /* CONFIG_SMP */ ++ ++/* ++ * This is the main, per-CPU runqueue data structure. ++ * This data should only be modified by the local cpu. ++ */ ++struct rq { ++ raw_spinlock_t *lock; ++ raw_spinlock_t *orig_lock; ++ ++ struct task_struct *curr, *idle, *stop; ++ struct mm_struct *prev_mm; ++ ++ unsigned int nr_running; ++ /* ++ * This is part of a global counter where only the total sum ++ * over all CPUs matters. A task can increase this counter on ++ * one CPU and if it got migrated afterwards it may decrease ++ * it on another CPU. Always updated under the runqueue lock: ++ */ ++ unsigned long nr_uninterruptible; ++ u64 nr_switches; ++ ++ /* Stored data about rq->curr to work outside rq lock */ ++ u64 rq_deadline; ++ int rq_prio; ++ ++ /* Best queued id for use outside lock */ ++ u64 best_key; ++ ++ unsigned long last_scheduler_tick; /* Last jiffy this RQ ticked */ ++ unsigned long last_jiffy; /* Last jiffy this RQ updated rq clock */ ++ u64 niffies; /* Last time this RQ updated rq clock */ ++ u64 last_niffy; /* Last niffies as updated by local clock */ ++ u64 last_jiffy_niffies; /* Niffies @ last_jiffy */ ++ ++ u64 load_update; /* When we last updated load */ ++ unsigned long load_avg; /* Rolling load average */ ++#ifdef HAVE_SCHED_AVG_IRQ ++ u64 irq_load_update; /* When we last updated IRQ load */ ++ unsigned long irq_load_avg; /* Rolling IRQ load average */ ++#endif ++#ifdef CONFIG_SMT_NICE ++ struct mm_struct *rq_mm; ++ int rq_smt_bias; /* Policy/nice level bias across smt siblings */ ++#endif ++ /* Accurate timekeeping data */ ++ unsigned long user_ns, nice_ns, irq_ns, softirq_ns, system_ns, ++ iowait_ns, idle_ns; ++ atomic_t nr_iowait; ++ ++ skiplist_node *node; ++ skiplist *sl; ++#ifdef CONFIG_SMP ++ struct task_struct *preempt; /* Preempt triggered on this task */ ++ struct task_struct *preempting; /* Hint only, what task is preempting */ ++ ++ int cpu; /* cpu of this runqueue */ ++ bool online; ++ ++ struct root_domain *rd; ++ struct sched_domain *sd; ++ ++ unsigned long cpu_capacity_orig; ++ ++ int *cpu_locality; /* CPU relative cache distance */ ++ struct rq **rq_order; /* Shared RQs ordered by relative cache distance */ ++ struct rq **cpu_order; /* RQs of discrete CPUs ordered by distance */ ++ ++ struct rq *smp_leader; /* First physical CPU per node */ ++#ifdef CONFIG_SCHED_SMT ++ struct rq *smt_leader; /* First logical CPU in SMT siblings */ ++ cpumask_t thread_mask; ++ bool (*siblings_idle)(struct rq *rq); ++ /* See if all smt siblings are idle */ ++#endif /* CONFIG_SCHED_SMT */ ++#ifdef CONFIG_SCHED_MC ++ struct rq *mc_leader; /* First logical CPU in MC siblings */ ++ cpumask_t core_mask; ++ bool (*cache_idle)(struct rq *rq); ++ /* See if all cache siblings are idle */ ++#endif /* CONFIG_SCHED_MC */ ++#endif /* CONFIG_SMP */ ++#ifdef CONFIG_IRQ_TIME_ACCOUNTING ++ u64 prev_irq_time; ++#endif /* CONFIG_IRQ_TIME_ACCOUNTING */ ++#ifdef CONFIG_PARAVIRT ++ u64 prev_steal_time; ++#endif /* CONFIG_PARAVIRT */ ++#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING ++ u64 prev_steal_time_rq; ++#endif /* CONFIG_PARAVIRT_TIME_ACCOUNTING */ ++ ++ u64 clock, old_clock, last_tick; ++ u64 clock_task; ++ int dither; ++ ++ int iso_ticks; ++ bool iso_refractory; ++ ++#ifdef CONFIG_HIGH_RES_TIMERS ++ struct hrtimer hrexpiry_timer; ++#endif ++ ++ int rt_nr_running; /* Number real time tasks running */ ++#ifdef CONFIG_SCHEDSTATS ++ ++ /* latency stats */ ++ struct sched_info rq_sched_info; ++ unsigned long long rq_cpu_time; ++ /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */ ++ ++ /* sys_sched_yield() stats */ ++ unsigned int yld_count; ++ ++ /* schedule() stats */ ++ unsigned int sched_switch; ++ unsigned int sched_count; ++ unsigned int sched_goidle; ++ ++ /* try_to_wake_up() stats */ ++ unsigned int ttwu_count; ++ unsigned int ttwu_local; ++#endif /* CONFIG_SCHEDSTATS */ ++ ++#ifdef CONFIG_SMP ++ struct llist_head wake_list; ++#endif ++ ++#ifdef CONFIG_CPU_IDLE ++ /* Must be inspected within a rcu lock section */ ++ struct cpuidle_state *idle_state; ++#endif ++}; ++ ++#ifdef CONFIG_SMP ++struct rq *cpu_rq(int cpu); ++#endif ++ ++#ifndef CONFIG_SMP ++extern struct rq *uprq; ++#define cpu_rq(cpu) (uprq) ++#define this_rq() (uprq) ++#define raw_rq() (uprq) ++#define task_rq(p) (uprq) ++#define cpu_curr(cpu) ((uprq)->curr) ++#else /* CONFIG_SMP */ ++DECLARE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); ++#define this_rq() this_cpu_ptr(&runqueues) ++#define raw_rq() raw_cpu_ptr(&runqueues) ++#define task_rq(p) cpu_rq(task_cpu(p)) ++#endif /* CONFIG_SMP */ ++ ++static inline int task_current(struct rq *rq, struct task_struct *p) ++{ ++ return rq->curr == p; ++} ++ ++static inline int task_running(struct rq *rq, struct task_struct *p) ++{ ++#ifdef CONFIG_SMP ++ return p->on_cpu; ++#else ++ return task_current(rq, p); ++#endif ++} ++ ++static inline void rq_lock(struct rq *rq) ++ __acquires(rq->lock) ++{ ++ raw_spin_lock(rq->lock); ++} ++ ++static inline void rq_unlock(struct rq *rq) ++ __releases(rq->lock) ++{ ++ raw_spin_unlock(rq->lock); ++} ++ ++static inline void rq_lock_irq(struct rq *rq) ++ __acquires(rq->lock) ++{ ++ raw_spin_lock_irq(rq->lock); ++} ++ ++static inline void rq_unlock_irq(struct rq *rq) ++ __releases(rq->lock) ++{ ++ raw_spin_unlock_irq(rq->lock); ++} ++ ++static inline void rq_lock_irqsave(struct rq *rq, unsigned long *flags) ++ __acquires(rq->lock) ++{ ++ raw_spin_lock_irqsave(rq->lock, *flags); ++} ++ ++static inline void rq_unlock_irqrestore(struct rq *rq, unsigned long *flags) ++ __releases(rq->lock) ++{ ++ raw_spin_unlock_irqrestore(rq->lock, *flags); ++} ++ ++static inline struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) ++ __acquires(p->pi_lock) ++ __acquires(rq->lock) ++{ ++ struct rq *rq; ++ ++ while (42) { ++ raw_spin_lock_irqsave(&p->pi_lock, *flags); ++ rq = task_rq(p); ++ raw_spin_lock(rq->lock); ++ if (likely(rq == task_rq(p))) ++ break; ++ raw_spin_unlock(rq->lock); ++ raw_spin_unlock_irqrestore(&p->pi_lock, *flags); ++ } ++ return rq; ++} ++ ++static inline void task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags) ++ __releases(rq->lock) ++ __releases(p->pi_lock) ++{ ++ rq_unlock(rq); ++ raw_spin_unlock_irqrestore(&p->pi_lock, *flags); ++} ++ ++static inline struct rq *__task_rq_lock(struct task_struct *p) ++ __acquires(rq->lock) ++{ ++ struct rq *rq; ++ ++ lockdep_assert_held(&p->pi_lock); ++ ++ while (42) { ++ rq = task_rq(p); ++ raw_spin_lock(rq->lock); ++ if (likely(rq == task_rq(p))) ++ break; ++ raw_spin_unlock(rq->lock); ++ } ++ return rq; ++} ++ ++static inline void __task_rq_unlock(struct rq *rq) ++{ ++ rq_unlock(rq); ++} ++ ++/* ++ * {de,en}queue flags: Most not used on MuQSS. ++ * ++ * DEQUEUE_SLEEP - task is no longer runnable ++ * ENQUEUE_WAKEUP - task just became runnable ++ * ++ * SAVE/RESTORE - an otherwise spurious dequeue/enqueue, done to ensure tasks ++ * are in a known state which allows modification. Such pairs ++ * should preserve as much state as possible. ++ * ++ * MOVE - paired with SAVE/RESTORE, explicitly does not preserve the location ++ * in the runqueue. ++ * ++ * ENQUEUE_HEAD - place at front of runqueue (tail if not specified) ++ * ENQUEUE_REPLENISH - CBS (replenish runtime and postpone deadline) ++ * ENQUEUE_MIGRATED - the task was migrated during wakeup ++ * ++ */ ++ ++#define DEQUEUE_SAVE 0x02 /* matches ENQUEUE_RESTORE */ ++ ++#define ENQUEUE_RESTORE 0x02 ++ ++static inline u64 __rq_clock_broken(struct rq *rq) ++{ ++ return READ_ONCE(rq->clock); ++} ++ ++static inline u64 rq_clock(struct rq *rq) ++{ ++ lockdep_assert_held(rq->lock); ++ ++ return rq->clock; ++} ++ ++static inline u64 rq_clock_task(struct rq *rq) ++{ ++ lockdep_assert_held(rq->lock); ++ ++ return rq->clock_task; ++} ++ ++#ifdef CONFIG_NUMA ++enum numa_topology_type { ++ NUMA_DIRECT, ++ NUMA_GLUELESS_MESH, ++ NUMA_BACKPLANE, ++}; ++extern enum numa_topology_type sched_numa_topology_type; ++extern int sched_max_numa_distance; ++extern bool find_numa_distance(int distance); ++ ++extern void sched_init_numa(void); ++extern void sched_domains_numa_masks_set(unsigned int cpu); ++extern void sched_domains_numa_masks_clear(unsigned int cpu); ++#else ++static inline void sched_init_numa(void) { } ++static inline void sched_domains_numa_masks_set(unsigned int cpu) { } ++static inline void sched_domains_numa_masks_clear(unsigned int cpu) { } ++#endif ++ ++extern struct mutex sched_domains_mutex; ++extern struct static_key_false sched_schedstats; ++ ++#define rcu_dereference_check_sched_domain(p) \ ++ rcu_dereference_check((p), \ ++ lockdep_is_held(&sched_domains_mutex)) ++ ++#ifdef CONFIG_SMP ++ ++/* ++ * The domain tree (rq->sd) is protected by RCU's quiescent state transition. ++ * See detach_destroy_domains: synchronize_sched for details. ++ * ++ * The domain tree of any CPU may only be accessed from within ++ * preempt-disabled sections. ++ */ ++#define for_each_domain(cpu, __sd) \ ++ for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); \ ++ __sd; __sd = __sd->parent) ++ ++#define for_each_lower_domain(sd) for (; sd; sd = sd->child) ++ ++/** ++ * highest_flag_domain - Return highest sched_domain containing flag. ++ * @cpu: The cpu whose highest level of sched domain is to ++ * be returned. ++ * @flag: The flag to check for the highest sched_domain ++ * for the given cpu. ++ * ++ * Returns the highest sched_domain of a cpu which contains the given flag. ++ */ ++static inline struct sched_domain *highest_flag_domain(int cpu, int flag) ++{ ++ struct sched_domain *sd, *hsd = NULL; ++ ++ for_each_domain(cpu, sd) { ++ if (!(sd->flags & flag)) ++ break; ++ hsd = sd; ++ } ++ ++ return hsd; ++} ++ ++static inline struct sched_domain *lowest_flag_domain(int cpu, int flag) ++{ ++ struct sched_domain *sd; ++ ++ for_each_domain(cpu, sd) { ++ if (sd->flags & flag) ++ break; ++ } ++ ++ return sd; ++} ++ ++DECLARE_PER_CPU(struct sched_domain *, sd_llc); ++DECLARE_PER_CPU(int, sd_llc_size); ++DECLARE_PER_CPU(int, sd_llc_id); ++DECLARE_PER_CPU(struct sched_domain_shared *, sd_llc_shared); ++DECLARE_PER_CPU(struct sched_domain *, sd_numa); ++DECLARE_PER_CPU(struct sched_domain *, sd_asym); ++ ++struct sched_group_capacity { ++ atomic_t ref; ++ /* ++ * CPU capacity of this group, SCHED_CAPACITY_SCALE being max capacity ++ * for a single CPU. ++ */ ++ unsigned long capacity; ++ unsigned long min_capacity; /* Min per-CPU capacity in group */ ++ unsigned long next_update; ++ int imbalance; /* XXX unrelated to capacity but shared group state */ ++ ++#ifdef CONFIG_SCHED_DEBUG ++ int id; ++#endif ++ ++ unsigned long cpumask[0]; /* balance mask */ ++}; ++ ++struct sched_group { ++ struct sched_group *next; /* Must be a circular list */ ++ atomic_t ref; ++ ++ unsigned int group_weight; ++ struct sched_group_capacity *sgc; ++ int asym_prefer_cpu; /* cpu of highest priority in group */ ++ ++ /* ++ * The CPUs this group covers. ++ * ++ * NOTE: this field is variable length. (Allocated dynamically ++ * by attaching extra space to the end of the structure, ++ * depending on how many CPUs the kernel has booted up with) ++ */ ++ unsigned long cpumask[0]; ++}; ++ ++static inline struct cpumask *sched_group_span(struct sched_group *sg) ++{ ++ return to_cpumask(sg->cpumask); ++} ++ ++/* ++ * See build_balance_mask(). ++ */ ++static inline struct cpumask *group_balance_mask(struct sched_group *sg) ++{ ++ return to_cpumask(sg->sgc->cpumask); ++} ++ ++/** ++ * group_first_cpu - Returns the first cpu in the cpumask of a sched_group. ++ * @group: The group whose first cpu is to be returned. ++ */ ++static inline unsigned int group_first_cpu(struct sched_group *group) ++{ ++ return cpumask_first(sched_group_span(group)); ++} ++ ++ ++#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) ++void register_sched_domain_sysctl(void); ++void dirty_sched_domain_sysctl(int cpu); ++void unregister_sched_domain_sysctl(void); ++#else ++static inline void register_sched_domain_sysctl(void) ++{ ++} ++static inline void dirty_sched_domain_sysctl(int cpu) ++{ ++} ++static inline void unregister_sched_domain_sysctl(void) ++{ ++} ++#endif ++ ++extern void sched_ttwu_pending(void); ++extern void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask); ++extern void set_rq_online (struct rq *rq); ++extern void set_rq_offline(struct rq *rq); ++extern bool sched_smp_initialized; ++ ++static inline void update_group_capacity(struct sched_domain *sd, int cpu) ++{ ++} ++ ++static inline void trigger_load_balance(struct rq *rq) ++{ ++} ++ ++#define sched_feat(x) 0 ++ ++#else /* CONFIG_SMP */ ++ ++static inline void sched_ttwu_pending(void) { } ++ ++#endif /* CONFIG_SMP */ ++ ++#ifdef CONFIG_CPU_IDLE ++static inline void idle_set_state(struct rq *rq, ++ struct cpuidle_state *idle_state) ++{ ++ rq->idle_state = idle_state; ++} ++ ++static inline struct cpuidle_state *idle_get_state(struct rq *rq) ++{ ++ SCHED_WARN_ON(!rcu_read_lock_held()); ++ return rq->idle_state; ++} ++#else ++static inline void idle_set_state(struct rq *rq, ++ struct cpuidle_state *idle_state) ++{ ++} ++ ++static inline struct cpuidle_state *idle_get_state(struct rq *rq) ++{ ++ return NULL; ++} ++#endif ++ ++#ifdef CONFIG_SCHED_DEBUG ++extern bool sched_debug_enabled; ++#endif ++ ++extern void schedule_idle(void); ++ ++#ifdef CONFIG_IRQ_TIME_ACCOUNTING ++struct irqtime { ++ u64 total; ++ u64 tick_delta; ++ u64 irq_start_time; ++ struct u64_stats_sync sync; ++}; ++ ++DECLARE_PER_CPU(struct irqtime, cpu_irqtime); ++ ++/* ++ * Returns the irqtime minus the softirq time computed by ksoftirqd. ++ * Otherwise ksoftirqd's sum_exec_runtime is substracted its own runtime ++ * and never move forward. ++ */ ++static inline u64 irq_time_read(int cpu) ++{ ++ struct irqtime *irqtime = &per_cpu(cpu_irqtime, cpu); ++ unsigned int seq; ++ u64 total; ++ ++ do { ++ seq = __u64_stats_fetch_begin(&irqtime->sync); ++ total = irqtime->total; ++ } while (__u64_stats_fetch_retry(&irqtime->sync, seq)); ++ ++ return total; ++} ++#endif /* CONFIG_IRQ_TIME_ACCOUNTING */ ++ ++#ifdef CONFIG_SMP ++static inline int cpu_of(struct rq *rq) ++{ ++ return rq->cpu; ++} ++#else /* CONFIG_SMP */ ++static inline int cpu_of(struct rq *rq) ++{ ++ return 0; ++} ++#endif ++ ++#ifdef CONFIG_CPU_FREQ ++DECLARE_PER_CPU(struct update_util_data *, cpufreq_update_util_data); ++ ++static inline void cpufreq_trigger(struct rq *rq, unsigned int flags) ++{ ++ struct update_util_data *data; ++ ++ data = rcu_dereference_sched(*per_cpu_ptr(&cpufreq_update_util_data, ++ cpu_of(rq))); ++ ++ if (data) ++ data->func(data, rq->niffies, flags); ++} ++#else ++static inline void cpufreq_trigger(struct rq *rq, unsigned int flag) ++{ ++} ++#endif /* CONFIG_CPU_FREQ */ ++ ++#ifdef arch_scale_freq_capacity ++#ifndef arch_scale_freq_invariant ++#define arch_scale_freq_invariant() (true) ++#endif ++#else /* arch_scale_freq_capacity */ ++#define arch_scale_freq_invariant() (false) ++#endif ++ ++/* ++ * This should only be called when current == rq->idle. Dodgy workaround for ++ * when softirqs are pending and we are in the idle loop. Setting current to ++ * resched will kick us out of the idle loop and the softirqs will be serviced ++ * on our next pass through schedule(). ++ */ ++static inline bool softirq_pending(int cpu) ++{ ++ if (likely(!local_softirq_pending())) ++ return false; ++ set_tsk_need_resched(current); ++ return true; ++} ++ ++#ifdef CONFIG_64BIT ++static inline u64 read_sum_exec_runtime(struct task_struct *t) ++{ ++ return tsk_seruntime(t); ++} ++#else ++struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags); ++void task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags); ++ ++static inline u64 read_sum_exec_runtime(struct task_struct *t) ++{ ++ unsigned long flags; ++ u64 ns; ++ struct rq *rq; ++ ++ rq = task_rq_lock(t, &flags); ++ ns = tsk_seruntime(t); ++ task_rq_unlock(rq, t, &flags); ++ ++ return ns; ++} ++#endif ++ ++#ifndef arch_scale_freq_capacity ++static __always_inline ++unsigned long arch_scale_freq_capacity(int cpu) ++{ ++ return SCHED_CAPACITY_SCALE; ++} ++#endif ++ ++#ifdef CONFIG_NO_HZ_FULL ++extern bool sched_can_stop_tick(struct rq *rq); ++extern int __init sched_tick_offload_init(void); ++ ++/* ++ * Tick may be needed by tasks in the runqueue depending on their policy and ++ * requirements. If tick is needed, lets send the target an IPI to kick it out of ++ * nohz mode if necessary. ++ */ ++static inline void sched_update_tick_dependency(struct rq *rq) ++{ ++ int cpu; ++ ++ if (!tick_nohz_full_enabled()) ++ return; ++ ++ cpu = cpu_of(rq); ++ ++ if (!tick_nohz_full_cpu(cpu)) ++ return; ++ ++ if (sched_can_stop_tick(rq)) ++ tick_nohz_dep_clear_cpu(cpu, TICK_DEP_BIT_SCHED); ++ else ++ tick_nohz_dep_set_cpu(cpu, TICK_DEP_BIT_SCHED); ++} ++#else ++static inline int sched_tick_offload_init(void) { return 0; } ++static inline void sched_update_tick_dependency(struct rq *rq) { } ++#endif ++ ++#ifdef CONFIG_SMP ++ ++#ifndef arch_scale_cpu_capacity ++static __always_inline ++unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) ++{ ++ if (sd && (sd->flags & SD_SHARE_CPUCAPACITY) && (sd->span_weight > 1)) ++ return sd->smt_gain / sd->span_weight; ++ ++ return SCHED_CAPACITY_SCALE; ++} ++#endif ++#else ++#ifndef arch_scale_cpu_capacity ++static __always_inline ++unsigned long arch_scale_cpu_capacity(void __always_unused *sd, int cpu) ++{ ++ return SCHED_CAPACITY_SCALE; ++} ++#endif ++#endif ++ ++#define SCHED_FLAG_SUGOV 0x10000000 ++ ++static inline bool rt_rq_is_runnable(struct rq *rt_rq) ++{ ++ return rt_rq->rt_nr_running; ++} ++ ++#ifdef CONFIG_CPU_FREQ_GOV_SCHEDUTIL ++ ++static inline unsigned long cpu_bw_dl(struct rq *rq) ++{ ++ return 0; ++} ++ ++static inline unsigned long cpu_util_dl(struct rq *rq) ++{ ++ return 0; ++} ++ ++static inline unsigned long cpu_util_cfs(struct rq *rq) ++{ ++ unsigned long ret = READ_ONCE(rq->load_avg); ++ ++ if (ret > SCHED_CAPACITY_SCALE) ++ ret = SCHED_CAPACITY_SCALE; ++ return ret; ++} ++ ++static inline unsigned long cpu_util_rt(struct rq *rq) ++{ ++ unsigned long ret = READ_ONCE(rq->rt_nr_running); ++ ++ if (ret > SCHED_CAPACITY_SCALE) ++ ret = SCHED_CAPACITY_SCALE; ++ return ret; ++} ++ ++#ifdef HAVE_SCHED_AVG_IRQ ++static inline unsigned long cpu_util_irq(struct rq *rq) ++{ ++ unsigned long ret = READ_ONCE(rq->irq_load_avg); ++ ++ if (ret > SCHED_CAPACITY_SCALE) ++ ret = SCHED_CAPACITY_SCALE; ++ return ret; ++} ++ ++static inline ++unsigned long scale_irq_capacity(unsigned long util, unsigned long irq, unsigned long max) ++{ ++ util *= (max - irq); ++ util /= max; ++ ++ return util; ++ ++} ++#else ++static inline unsigned long cpu_util_irq(struct rq *rq) ++{ ++ return 0; ++} ++ ++static inline ++unsigned long scale_irq_capacity(unsigned long util, unsigned long irq, unsigned long max) ++{ ++ return util; ++} ++#endif ++#endif ++ ++#endif /* MUQSS_SCHED_H */ +diff -Nur a/kernel/sched/sched.h b/kernel/sched/sched.h +--- a/kernel/sched/sched.h 2019-02-06 16:30:16.000000000 +0000 ++++ b/kernel/sched/sched.h 2019-02-09 17:46:12.001297867 +0000 +@@ -2,6 +2,19 @@ + /* + * Scheduler internal types and methods: + */ ++#ifdef CONFIG_SCHED_MUQSS ++#include "MuQSS.h" ++ ++/* Begin compatibility wrappers for MuQSS/CFS differences */ ++#define rq_rt_nr_running(rq) ((rq)->rt_nr_running) ++#define rq_h_nr_running(rq) ((rq)->nr_running) ++ ++#else /* CONFIG_SCHED_MUQSS */ ++ ++#define rq_rt_nr_running(rq) ((rq)->rt.rt_nr_running) ++#define rq_h_nr_running(rq) ((rq)->cfs.h_nr_running) ++ ++ + #include <linux/sched.h> + + #include <linux/sched/autogroup.h> +@@ -2241,3 +2254,30 @@ + return util; + } + #endif ++ ++/* MuQSS compatibility functions */ ++static inline bool softirq_pending(int cpu) ++{ ++ return false; ++} ++ ++#ifdef CONFIG_64BIT ++static inline u64 read_sum_exec_runtime(struct task_struct *t) ++{ ++ return t->se.sum_exec_runtime; ++} ++#else ++static inline u64 read_sum_exec_runtime(struct task_struct *t) ++{ ++ u64 ns; ++ struct rq_flags rf; ++ struct rq *rq; ++ ++ rq = task_rq_lock(t, &rf); ++ ns = t->se.sum_exec_runtime; ++ task_rq_unlock(rq, t, &rf); ++ ++ return ns; ++} ++#endif ++#endif /* CONFIG_SCHED_MUQSS */ +diff -Nur a/kernel/sched/topology.c b/kernel/sched/topology.c +--- a/kernel/sched/topology.c 2019-02-06 16:30:16.000000000 +0000 ++++ b/kernel/sched/topology.c 2019-02-09 17:46:12.001297867 +0000 +@@ -219,7 +219,11 @@ + struct root_domain *old_rd = NULL; + unsigned long flags; + ++#ifdef CONFIG_SCHED_MUQSS ++ raw_spin_lock_irqsave(rq->lock, flags); ++#else + raw_spin_lock_irqsave(&rq->lock, flags); ++#endif + + if (rq->rd) { + old_rd = rq->rd; +@@ -245,7 +249,11 @@ + if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) + set_rq_online(rq); + ++#ifdef CONFIG_SCHED_MUQSS ++ raw_spin_unlock_irqrestore(rq->lock, flags); ++#else + raw_spin_unlock_irqrestore(&rq->lock, flags); ++#endif + + if (old_rd) + call_rcu_sched(&old_rd->rcu, free_rootdomain); +diff -Nur a/kernel/skip_list.c b/kernel/skip_list.c +--- a/kernel/skip_list.c 1970-01-01 01:00:00.000000000 +0100 ++++ b/kernel/skip_list.c 2019-02-09 17:46:12.001297867 +0000 +@@ -0,0 +1,148 @@ ++/* ++ Copyright (C) 2011,2016 Con Kolivas. ++ ++ Code based on example originally by William Pugh. ++ ++Skip Lists are a probabilistic alternative to balanced trees, as ++described in the June 1990 issue of CACM and were invented by ++William Pugh in 1987. ++ ++A couple of comments about this implementation: ++The routine randomLevel has been hard-coded to generate random ++levels using p=0.25. It can be easily changed. ++ ++The insertion routine has been implemented so as to use the ++dirty hack described in the CACM paper: if a random level is ++generated that is more than the current maximum level, the ++current maximum level plus one is used instead. ++ ++Levels start at zero and go up to MaxLevel (which is equal to ++MaxNumberOfLevels-1). ++ ++The routines defined in this file are: ++ ++init: defines slnode ++ ++new_skiplist: returns a new, empty list ++ ++randomLevel: Returns a random level based on a u64 random seed passed to it. ++In MuQSS, the "niffy" time is used for this purpose. ++ ++insert(l,key, value): inserts the binding (key, value) into l. This operation ++occurs in O(log n) time. ++ ++delnode(slnode, l, node): deletes any binding of key from the l based on the ++actual node value. This operation occurs in O(k) time where k is the ++number of levels of the node in question (max 8). The original delete ++function occurred in O(log n) time and involved a search. ++ ++MuQSS Notes: In this implementation of skiplists, there are bidirectional ++next/prev pointers and the insert function returns a pointer to the actual ++node the value is stored. The key here is chosen by the scheduler so as to ++sort tasks according to the priority list requirements and is no longer used ++by the scheduler after insertion. The scheduler lookup, however, occurs in ++O(1) time because it is always the first item in the level 0 linked list. ++Since the task struct stores a copy of the node pointer upon skiplist_insert, ++it can also remove it much faster than the original implementation with the ++aid of prev<->next pointer manipulation and no searching. ++ ++*/ ++ ++#include <linux/slab.h> ++#include <linux/skip_list.h> ++ ++#define MaxNumberOfLevels 8 ++#define MaxLevel (MaxNumberOfLevels - 1) ++ ++void skiplist_init(skiplist_node *slnode) ++{ ++ int i; ++ ++ slnode->key = 0xFFFFFFFFFFFFFFFF; ++ slnode->level = 0; ++ slnode->value = NULL; ++ for (i = 0; i < MaxNumberOfLevels; i++) ++ slnode->next[i] = slnode->prev[i] = slnode; ++} ++ ++skiplist *new_skiplist(skiplist_node *slnode) ++{ ++ skiplist *l = kzalloc(sizeof(skiplist), GFP_ATOMIC); ++ ++ BUG_ON(!l); ++ l->header = slnode; ++ return l; ++} ++ ++void free_skiplist(skiplist *l) ++{ ++ skiplist_node *p, *q; ++ ++ p = l->header; ++ do { ++ q = p->next[0]; ++ p->next[0]->prev[0] = q->prev[0]; ++ skiplist_node_init(p); ++ p = q; ++ } while (p != l->header); ++ kfree(l); ++} ++ ++void skiplist_node_init(skiplist_node *node) ++{ ++ memset(node, 0, sizeof(skiplist_node)); ++} ++ ++static inline unsigned int randomLevel(const long unsigned int randseed) ++{ ++ return find_first_bit(&randseed, MaxLevel) / 2; ++} ++ ++void skiplist_insert(skiplist *l, skiplist_node *node, keyType key, valueType value, unsigned int randseed) ++{ ++ skiplist_node *update[MaxNumberOfLevels]; ++ skiplist_node *p, *q; ++ int k = l->level; ++ ++ p = l->header; ++ do { ++ while (q = p->next[k], q->key <= key) ++ p = q; ++ update[k] = p; ++ } while (--k >= 0); ++ ++ ++l->entries; ++ k = randomLevel(randseed); ++ if (k > l->level) { ++ k = ++l->level; ++ update[k] = l->header; ++ } ++ ++ node->level = k; ++ node->key = key; ++ node->value = value; ++ do { ++ p = update[k]; ++ node->next[k] = p->next[k]; ++ p->next[k] = node; ++ node->prev[k] = p; ++ node->next[k]->prev[k] = node; ++ } while (--k >= 0); ++} ++ ++void skiplist_delete(skiplist *l, skiplist_node *node) ++{ ++ int k, m = node->level; ++ ++ for (k = 0; k <= m; k++) { ++ node->prev[k]->next[k] = node->next[k]; ++ node->next[k]->prev[k] = node->prev[k]; ++ } ++ skiplist_node_init(node); ++ if (m == l->level) { ++ while (l->header->next[m] == l->header && l->header->prev[m] == l->header && m > 0) ++ m--; ++ l->level = m; ++ } ++ l->entries--; ++} +diff -Nur a/kernel/sysctl.c b/kernel/sysctl.c +--- a/kernel/sysctl.c 2019-02-09 17:20:30.491821512 +0000 ++++ b/kernel/sysctl.c 2019-02-09 17:57:37.563468776 +0000 +@@ -136,6 +136,12 @@ + static unsigned long one_ul __read_only = 1; + static int one_hundred __read_only = 100; + static int one_thousand __read_only = 1000; ++#ifdef CONFIG_SCHED_MUQSS ++extern int rr_interval; ++extern int sched_interactive; ++extern int sched_iso_cpu; ++extern int sched_yield_type; ++#endif + #ifdef CONFIG_PRINTK + static int ten_thousand __read_only = 10000; + #endif +@@ -306,7 +312,7 @@ + { } + }; + +-#ifdef CONFIG_SCHED_DEBUG ++#if defined(CONFIG_SCHED_DEBUG) && !defined(CONFIG_SCHED_MUQSS) + static int min_sched_granularity_ns __read_only = 100000; /* 100 usecs */ + static int max_sched_granularity_ns __read_only = NSEC_PER_SEC; /* 1 second */ + static int min_wakeup_granularity_ns __read_only; /* 0 usecs */ +@@ -323,6 +329,7 @@ + #endif + + static struct ctl_table kern_table[] = { ++#ifndef CONFIG_SCHED_MUQSS + { + .procname = "sched_child_runs_first", + .data = &sysctl_sched_child_runs_first, +@@ -477,6 +484,7 @@ + .extra1 = &one, + }, + #endif ++#endif /* !CONFIG_SCHED_MUQSS */ + #ifdef CONFIG_PROVE_LOCKING + { + .procname = "prove_locking", +@@ -1082,6 +1090,44 @@ + .proc_handler = proc_dointvec, + }, + #endif ++#ifdef CONFIG_SCHED_MUQSS ++ { ++ .procname = "rr_interval", ++ .data = &rr_interval, ++ .maxlen = sizeof (int), ++ .mode = 0644, ++ .proc_handler = &proc_dointvec_minmax, ++ .extra1 = &one, ++ .extra2 = &one_thousand, ++ }, ++ { ++ .procname = "interactive", ++ .data = &sched_interactive, ++ .maxlen = sizeof(int), ++ .mode = 0644, ++ .proc_handler = &proc_dointvec_minmax, ++ .extra1 = &zero, ++ .extra2 = &one, ++ }, ++ { ++ .procname = "iso_cpu", ++ .data = &sched_iso_cpu, ++ .maxlen = sizeof (int), ++ .mode = 0644, ++ .proc_handler = &proc_dointvec_minmax, ++ .extra1 = &zero, ++ .extra2 = &one_hundred, ++ }, ++ { ++ .procname = "yield_type", ++ .data = &sched_yield_type, ++ .maxlen = sizeof (int), ++ .mode = 0644, ++ .proc_handler = &proc_dointvec_minmax, ++ .extra1 = &zero, ++ .extra2 = &two, ++ }, ++#endif + #if defined(CONFIG_S390) && defined(CONFIG_SMP) + { + .procname = "spin_retry", +diff -Nur a/kernel/time/clockevents.c b/kernel/time/clockevents.c +--- a/kernel/time/clockevents.c 2019-02-06 16:30:16.000000000 +0000 ++++ b/kernel/time/clockevents.c 2019-02-09 17:46:12.001297867 +0000 +@@ -198,8 +198,13 @@ + + #ifdef CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST + ++#ifdef CONFIG_SCHED_MUQSS ++/* Limit min_delta to 100us */ ++#define MIN_DELTA_LIMIT (NSEC_PER_SEC / 10000) ++#else + /* Limit min_delta to a jiffie */ + #define MIN_DELTA_LIMIT (NSEC_PER_SEC / HZ) ++#endif + + /** + * clockevents_increase_min_delta - raise minimum delta of a clock event device +diff -Nur a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c +--- a/kernel/time/posix-cpu-timers.c 2019-02-06 16:30:16.000000000 +0000 ++++ b/kernel/time/posix-cpu-timers.c 2019-02-09 17:46:12.001297867 +0000 +@@ -830,7 +830,7 @@ + tsk_expires->virt_exp = expires; + + tsk_expires->sched_exp = check_timers_list(++timers, firing, +- tsk->se.sum_exec_runtime); ++ tsk_seruntime(tsk)); + + /* + * Check for the special case thread timers. +@@ -840,7 +840,7 @@ + unsigned long hard = task_rlimit_max(tsk, RLIMIT_RTTIME); + + if (hard != RLIM_INFINITY && +- tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) { ++ tsk_rttimeout(tsk) > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) { + /* + * At the hard limit, we just die. + * No need to calculate anything else now. +@@ -852,7 +852,7 @@ + __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk); + return; + } +- if (tsk->rt.timeout > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) { ++ if (tsk_rttimeout(tsk) > DIV_ROUND_UP(soft, USEC_PER_SEC/HZ)) { + /* + * At the soft limit, send a SIGXCPU every second. + */ +@@ -1095,7 +1095,7 @@ + struct task_cputime task_sample; + + task_cputime(tsk, &task_sample.utime, &task_sample.stime); +- task_sample.sum_exec_runtime = tsk->se.sum_exec_runtime; ++ task_sample.sum_exec_runtime = tsk_seruntime(tsk); + if (task_cputime_expired(&task_sample, &tsk->cputime_expires)) + return 1; + } +diff -Nur a/kernel/time/timer.c b/kernel/time/timer.c +--- a/kernel/time/timer.c 2019-02-09 17:20:30.491821512 +0000 ++++ b/kernel/time/timer.c 2019-02-09 17:46:12.001297867 +0000 +@@ -1479,7 +1479,7 @@ + * Check, if the next hrtimer event is before the next timer wheel + * event: + */ +-static u64 cmp_next_hrtimer_event(u64 basem, u64 expires) ++static u64 cmp_next_hrtimer_event(struct timer_base *base, u64 basem, u64 expires) + { + u64 nextevt = hrtimer_get_next_event(); + +@@ -1497,6 +1497,9 @@ + if (nextevt <= basem) + return basem; + ++ if (nextevt < expires && nextevt - basem <= TICK_NSEC) ++ base->is_idle = false; ++ + /* + * Round up to the next jiffie. High resolution timers are + * off, so the hrtimers are expired in the tick and we need to +@@ -1566,7 +1569,7 @@ + } + raw_spin_unlock(&base->lock); + +- return cmp_next_hrtimer_event(basem, expires); ++ return cmp_next_hrtimer_event(base, basem, expires); + } + + /** +diff -Nur a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c +--- a/kernel/trace/trace_selftest.c 2019-02-06 16:30:16.000000000 +0000 ++++ b/kernel/trace/trace_selftest.c 2019-02-09 17:46:12.001297867 +0000 +@@ -1041,10 +1041,15 @@ + { + /* Make this a -deadline thread */ + static const struct sched_attr attr = { ++#ifdef CONFIG_SCHED_MUQSS ++ /* No deadline on MuQSS, use RR */ ++ .sched_policy = SCHED_RR, ++#else + .sched_policy = SCHED_DEADLINE, + .sched_runtime = 100000ULL, + .sched_deadline = 10000000ULL, + .sched_period = 10000000ULL ++#endif + }; + struct wakeup_test_data *x = data; + |