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2018-12-11sched/core: Remove unnecessary unlikely() in push_*_task()Yangtao Li
WARN_ON() already contains an unlikely(), so it's not necessary to use WARN_ON(1). Signed-off-by: Yangtao Li <tiny.windzz@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20181103172602.1917-1-tiny.windzz@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-11-04sched/core: Introduce set_next_task() helper for better code readabilityMuchun Song
When we pick the next task, we will do the following for the task: 1) p->se.exec_start = rq_clock_task(rq); 2) dequeue_pushable(_dl)_task(rq, p); When we call set_curr_task(), we also need to do the same thing above. In rt.c, the code at 1) is in the _pick_next_task_rt() and the code at 2) is in the pick_next_task_rt(). If we put two operations in one function, maybe better. So, we introduce a new function set_next_task(), which is responsible for doing the above. By introducing the function we can get rid of calling the dequeue_pushable(_dl)_task() directly(We can call set_next_task()) in pick_next_task() and have better code readability and reuse. In set_curr_task_rt(), we also can call set_next_task(). Do this things such that we end up with: static struct task_struct *pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) { /* do something else ... */ put_prev_task(rq, prev); /* pick next task p */ set_next_task(rq, p); /* do something else ... */ } put_prev_task() can match set_next_task(), which can make the code more readable. Signed-off-by: Muchun Song <smuchun@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20181026131743.21786-1-smuchun@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-10-29sched/rt: Update comment in pick_next_task_rt()Muchun Song
Commit: f4ebcbc0d7e0 ("sched/rt: Substract number of tasks of throttled queues from rq->nr_running") added a new rt_rq->rt_queued field, which is used to indicate the status of rq->rt enqueue or dequeue. So, the ->rt_nr_running check was removed and we now check ->rt_queued instead. Fix the comment in pick_next_task_rt() as well, which was still referencing the old logic. Signed-off-by: Muchun Song <smuchun@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20181027030517.23292-1-smuchun@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-07-25Merge branch 'sched/urgent' into sched/core, to pick up fixesIngo Molnar
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-07-25sched/rt: Restore rt_runtime after disabling RT_RUNTIME_SHAREHailong Liu
NO_RT_RUNTIME_SHARE feature is used to prevent a CPU borrow enough runtime with a spin-rt-task. However, if RT_RUNTIME_SHARE feature is enabled and rt_rq has borrowd enough rt_runtime at the beginning, rt_runtime can't be restored to its initial bandwidth rt_runtime after we disable RT_RUNTIME_SHARE. E.g. on my PC with 4 cores, procedure to reproduce: 1) Make sure RT_RUNTIME_SHARE is enabled cat /sys/kernel/debug/sched_features GENTLE_FAIR_SLEEPERS START_DEBIT NO_NEXT_BUDDY LAST_BUDDY CACHE_HOT_BUDDY WAKEUP_PREEMPTION NO_HRTICK NO_DOUBLE_TICK LB_BIAS NONTASK_CAPACITY TTWU_QUEUE NO_SIS_AVG_CPU SIS_PROP NO_WARN_DOUBLE_CLOCK RT_PUSH_IPI RT_RUNTIME_SHARE NO_LB_MIN ATTACH_AGE_LOAD WA_IDLE WA_WEIGHT WA_BIAS 2) Start a spin-rt-task ./loop_rr & 3) set affinity to the last cpu taskset -p 8 $pid_of_loop_rr 4) Observe that last cpu have borrowed enough runtime. cat /proc/sched_debug | grep rt_runtime .rt_runtime : 950.000000 .rt_runtime : 900.000000 .rt_runtime : 950.000000 .rt_runtime : 1000.000000 5) Disable RT_RUNTIME_SHARE echo NO_RT_RUNTIME_SHARE > /sys/kernel/debug/sched_features 6) Observe that rt_runtime can not been restored cat /proc/sched_debug | grep rt_runtime .rt_runtime : 950.000000 .rt_runtime : 900.000000 .rt_runtime : 950.000000 .rt_runtime : 1000.000000 This patch help to restore rt_runtime after we disable RT_RUNTIME_SHARE. Signed-off-by: Hailong Liu <liu.hailong6@zte.com.cn> Signed-off-by: Jiang Biao <jiang.biao2@zte.com.cn> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: zhong.weidong@zte.com.cn Link: http://lkml.kernel.org/r/1531874815-39357-1-git-send-email-liu.hailong6@zte.com.cn Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-07-16sched/core: Use PELT for scale_rt_capacity()Vincent Guittot
The utilization of the CPU by RT, DL and IRQs are now tracked with PELT so we can use these metrics instead of rt_avg to evaluate the remaining capacity available for CFS class. scale_rt_capacity() behavior has been changed and now returns the remaining capacity available for CFS instead of a scaling factor because RT, DL and IRQ provide now absolute utilization value. The same formula as schedutil is used: IRQ util_avg + (1 - IRQ util_avg / max capacity ) * /Sum rq util_avg but the implementation is different because it doesn't return the same value and doesn't benefit of the same optimization. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten.Rasmussen@arm.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: claudio@evidence.eu.com Cc: daniel.lezcano@linaro.org Cc: dietmar.eggemann@arm.com Cc: joel@joelfernandes.org Cc: juri.lelli@redhat.com Cc: luca.abeni@santannapisa.it Cc: patrick.bellasi@arm.com Cc: quentin.perret@arm.com Cc: rjw@rjwysocki.net Cc: valentin.schneider@arm.com Cc: viresh.kumar@linaro.org Link: http://lkml.kernel.org/r/1530200714-4504-10-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-07-15sched/rt: Add rt_rq utilization trackingVincent Guittot
schedutil governor relies on cfs_rq's util_avg to choose the OPP when CFS tasks are running. When the CPU is overloaded by CFS and RT tasks, CFS tasks are preempted by RT tasks and in this case util_avg reflects the remaining capacity but not what CFS want to use. In such case, schedutil can select a lower OPP whereas the CPU is overloaded. In order to have a more accurate view of the utilization of the CPU, we track the utilization of RT tasks. Only util_avg is correctly tracked but not load_avg and runnable_load_avg which are useless for rt_rq. rt_rq uses rq_clock_task and cfs_rq uses cfs_rq_clock_task but they are the same at the root group level, so the PELT windows of the util_sum are aligned. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten.Rasmussen@arm.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: claudio@evidence.eu.com Cc: daniel.lezcano@linaro.org Cc: dietmar.eggemann@arm.com Cc: joel@joelfernandes.org Cc: juri.lelli@redhat.com Cc: luca.abeni@santannapisa.it Cc: patrick.bellasi@arm.com Cc: quentin.perret@arm.com Cc: rjw@rjwysocki.net Cc: valentin.schneider@arm.com Cc: viresh.kumar@linaro.org Link: http://lkml.kernel.org/r/1530200714-4504-3-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-07-03sched/rt: Fix call to cpufreq_update_util()Vincent Guittot
With commit: 8f111bc357aa ("cpufreq/schedutil: Rewrite CPUFREQ_RT support") the schedutil governor uses rq->rt.rt_nr_running to detect whether an RT task is currently running on the CPU and to set frequency to max if necessary. cpufreq_update_util() is called in enqueue/dequeue_top_rt_rq() but rq->rt.rt_nr_running has not been updated yet when dequeue_top_rt_rq() is called so schedutil still considers that an RT task is running when the last task is dequeued. The update of rq->rt.rt_nr_running happens later in dequeue_rt_stack(). In fact, we can take advantage of the sequence that the dequeue then re-enqueue rt entities when a rt task is enqueued or dequeued; As a result enqueue_top_rt_rq() is always called when a task is enqueued or dequeued and also when groups are throttled or unthrottled. The only place that not use enqueue_top_rt_rq() is when root rt_rq is throttled. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: efault@gmx.de Cc: juri.lelli@redhat.com Cc: patrick.bellasi@arm.com Cc: viresh.kumar@linaro.org Fixes: 8f111bc357aa ('cpufreq/schedutil: Rewrite CPUFREQ_RT support') Link: http://lkml.kernel.org/r/1530021202-21695-1-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-06-12treewide: kzalloc() -> kcalloc()Kees Cook
The kzalloc() function has a 2-factor argument form, kcalloc(). This patch replaces cases of: kzalloc(a * b, gfp) with: kcalloc(a * b, gfp) as well as handling cases of: kzalloc(a * b * c, gfp) with: kzalloc(array3_size(a, b, c), gfp) as it's slightly less ugly than: kzalloc_array(array_size(a, b), c, gfp) This does, however, attempt to ignore constant size factors like: kzalloc(4 * 1024, gfp) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( kzalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | kzalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( kzalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(char) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(u8) * COUNT + COUNT , ...) | kzalloc( - sizeof(__u8) * COUNT + COUNT , ...) | kzalloc( - sizeof(char) * COUNT + COUNT , ...) | kzalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( - kzalloc + kcalloc ( - sizeof(TYPE) * (COUNT_ID) + COUNT_ID, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * COUNT_ID + COUNT_ID, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * (COUNT_CONST) + COUNT_CONST, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * COUNT_CONST + COUNT_CONST, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (COUNT_ID) + COUNT_ID, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * COUNT_ID + COUNT_ID, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (COUNT_CONST) + COUNT_CONST, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * COUNT_CONST + COUNT_CONST, sizeof(THING) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ - kzalloc + kcalloc ( - SIZE * COUNT + COUNT, SIZE , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( kzalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( kzalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kzalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kzalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( kzalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products, // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( kzalloc(C1 * C2 * C3, ...) | kzalloc( - (E1) * E2 * E3 + array3_size(E1, E2, E3) , ...) | kzalloc( - (E1) * (E2) * E3 + array3_size(E1, E2, E3) , ...) | kzalloc( - (E1) * (E2) * (E3) + array3_size(E1, E2, E3) , ...) | kzalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants, // keeping sizeof() as the second factor argument. @@ expression THING, E1, E2; type TYPE; constant C1, C2, C3; @@ ( kzalloc(sizeof(THING) * C2, ...) | kzalloc(sizeof(TYPE) * C2, ...) | kzalloc(C1 * C2 * C3, ...) | kzalloc(C1 * C2, ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * (E2) + E2, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * E2 + E2, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (E2) + E2, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * E2 + E2, sizeof(THING) , ...) | - kzalloc + kcalloc ( - (E1) * E2 + E1, E2 , ...) | - kzalloc + kcalloc ( - (E1) * (E2) + E1, E2 , ...) | - kzalloc + kcalloc ( - E1 * E2 + E1, E2 , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-05-18sched/debug: Move the print_rt_rq() and print_dl_rq() declarations to ↵Mathieu Malaterre
kernel/sched/sched.h In the following commit: 6b55c9654fcc ("sched/debug: Move print_cfs_rq() declaration to kernel/sched/sched.h") the print_cfs_rq() prototype was added to <kernel/sched/sched.h>, right next to the prototypes for print_cfs_stats(), print_rt_stats() and print_dl_stats(). Finish this previous commit and also move related prototypes for print_rt_rq() and print_dl_rq(). Remove existing extern declarations now that they not needed anymore. Silences the following GCC warning, triggered by W=1: kernel/sched/debug.c:573:6: warning: no previous prototype for ‘print_rt_rq’ [-Wmissing-prototypes] kernel/sched/debug.c:603:6: warning: no previous prototype for ‘print_dl_rq’ [-Wmissing-prototypes] Signed-off-by: Mathieu Malaterre <malat@debian.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180516195348.30426-1-malat@debian.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-04-05sched/core: Simplify helpers for rq clock update skip requestsDavidlohr Bueso
By renaming the functions we can get rid of the skip parameter and have better code redability. It makes zero sense to have things such as: rq_clock_skip_update(rq, false) When the skip request is in fact not going to happen. Ever. Rename things such that we end up with: rq_clock_skip_update(rq) rq_clock_cancel_skipupdate(rq) Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Cc: matt@codeblueprint.co.uk Cc: rostedt@goodmis.org Link: http://lkml.kernel.org/r/20180404161539.nhadkff2aats74jh@linux-n805 Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-04-05sched/rt: Fix rq->clock_update_flags < RQCF_ACT_SKIP warningDavidlohr Bueso
While running rt-tests' pi_stress program I got the following splat: rq->clock_update_flags < RQCF_ACT_SKIP WARNING: CPU: 27 PID: 0 at kernel/sched/sched.h:960 assert_clock_updated.isra.38.part.39+0x13/0x20 [...] <IRQ> enqueue_top_rt_rq+0xf4/0x150 ? cpufreq_dbs_governor_start+0x170/0x170 sched_rt_rq_enqueue+0x65/0x80 sched_rt_period_timer+0x156/0x360 ? sched_rt_rq_enqueue+0x80/0x80 __hrtimer_run_queues+0xfa/0x260 hrtimer_interrupt+0xcb/0x220 smp_apic_timer_interrupt+0x62/0x120 apic_timer_interrupt+0xf/0x20 </IRQ> [...] do_idle+0x183/0x1e0 cpu_startup_entry+0x5f/0x70 start_secondary+0x192/0x1d0 secondary_startup_64+0xa5/0xb0 We can get rid of it be the "traditional" means of adding an update_rq_clock() call after acquiring the rq->lock in do_sched_rt_period_timer(). The case for the RT task throttling (which this workload also hits) can be ignored in that the skip_update call is actually bogus and quite the contrary (the request bits are removed/reverted). By setting RQCF_UPDATED we really don't care if the skip is happening or not and will therefore make the assert_clock_updated() check happy. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dave@stgolabs.net Cc: linux-kernel@vger.kernel.org Cc: rostedt@goodmis.org Link: http://lkml.kernel.org/r/20180402164954.16255-1-dave@stgolabs.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-09cpufreq/schedutil: Rewrite CPUFREQ_RT supportPeter Zijlstra
Instead of trying to duplicate scheduler state to track if an RT task is running, directly use the scheduler runqueue state for it. This vastly simplifies things and fixes a number of bugs related to sugov and the scheduler getting out of sync wrt this state. As a consequence we not also update the remove cfs/dl state when iterating the shared mask. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-04sched/deadline, rt: Rename queue_push_tasks/queue_pull_task to create ↵Ingo Molnar
separate namespace There are similarly named functions in both of these modules: kernel/sched/deadline.c:static inline void queue_push_tasks(struct rq *rq) kernel/sched/deadline.c:static inline void queue_pull_task(struct rq *rq) kernel/sched/deadline.c:static inline void queue_push_tasks(struct rq *rq) kernel/sched/deadline.c:static inline void queue_pull_task(struct rq *rq) kernel/sched/deadline.c: queue_push_tasks(rq); kernel/sched/deadline.c: queue_pull_task(rq); kernel/sched/deadline.c: queue_push_tasks(rq); kernel/sched/deadline.c: queue_pull_task(rq); kernel/sched/rt.c:static inline void queue_push_tasks(struct rq *rq) kernel/sched/rt.c:static inline void queue_pull_task(struct rq *rq) kernel/sched/rt.c:static inline void queue_push_tasks(struct rq *rq) kernel/sched/rt.c: queue_push_tasks(rq); kernel/sched/rt.c: queue_pull_task(rq); kernel/sched/rt.c: queue_push_tasks(rq); kernel/sched/rt.c: queue_pull_task(rq); ... which makes it harder to grep for them. Prefix them with deadline_ and rt_, respectively. Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-04sched/headers: Simplify and clean up header usage in the schedulerIngo Molnar
Do the following cleanups and simplifications: - sched/sched.h already includes <asm/paravirt.h>, so no need to include it in sched/core.c again. - order the <linux/sched/*.h> headers alphabetically - add all <linux/sched/*.h> headers to kernel/sched/sched.h - remove all unnecessary includes from the .c files that are already included in kernel/sched/sched.h. Finally, make all scheduler .c files use a single common header: #include "sched.h" ... which now contains a union of the relied upon headers. This makes the various .c files easier to read and easier to handle. Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-03-03sched: Clean up and harmonize the coding style of the scheduler code baseIngo Molnar
A good number of small style inconsistencies have accumulated in the scheduler core, so do a pass over them to harmonize all these details: - fix speling in comments, - use curly braces for multi-line statements, - remove unnecessary parentheses from integer literals, - capitalize consistently, - remove stray newlines, - add comments where necessary, - remove invalid/unnecessary comments, - align structure definitions and other data types vertically, - add missing newlines for increased readability, - fix vertical tabulation where it's misaligned, - harmonize preprocessor conditional block labeling and vertical alignment, - remove line-breaks where they uglify the code, - add newline after local variable definitions, No change in functionality: md5: 1191fa0a890cfa8132156d2959d7e9e2 built-in.o.before.asm 1191fa0a890cfa8132156d2959d7e9e2 built-in.o.after.asm Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-21sched/isolation: Offload residual 1Hz scheduler tickFrederic Weisbecker
When a CPU runs in full dynticks mode, a 1Hz tick remains in order to keep the scheduler stats alive. However this residual tick is a burden for bare metal tasks that can't stand any interruption at all, or want to minimize them. The usual boot parameters "nohz_full=" or "isolcpus=nohz" will now outsource these scheduler ticks to the global workqueue so that a housekeeping CPU handles those remotely. The sched_class::task_tick() implementations have been audited and look safe to be called remotely as the target runqueue and its current task are passed in parameter and don't seem to be accessed locally. Note that in the case of using isolcpus, it's still up to the user to affine the global workqueues to the housekeeping CPUs through /sys/devices/virtual/workqueue/cpumask or domains isolation "isolcpus=nohz,domain". Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Christoph Lameter <cl@linux.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Cc: Wanpeng Li <kernellwp@gmail.com> Link: http://lkml.kernel.org/r/1519186649-3242-6-git-send-email-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-13sched/rt: Make update_curr_rt() more accurateWen Yang
rq->clock_task may be updated between the two calls of rq_clock_task() in update_curr_rt(). Calling rq_clock_task() only once makes it more accurate and efficient, taking update_curr() as reference. Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Jiang Biao <jiang.biao2@zte.com.cn> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: zhong.weidong@zte.com.cn Link: http://lkml.kernel.org/r/1517882008-44552-1-git-send-email-wen.yang99@zte.com.cn Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-06sched/rt: Make update_curr_rt() more accurateWen Yang
rq->clock_task may be updated between the two calls of rq_clock_task() in update_curr_rt(). Calling rq_clock_task() only once makes it more accurate and efficient, taking update_curr() as reference. Signed-off-by: Wen Yang <wen.yang99@zte.com.cn> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Jiang Biao <jiang.biao2@zte.com.cn> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: zhong.weidong@zte.com.cn Link: http://lkml.kernel.org/r/1517800721-42092-1-git-send-email-wen.yang99@zte.com.cn Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-06sched/rt: Up the root domain ref count when passing it around via IPIsSteven Rostedt (VMware)
When issuing an IPI RT push, where an IPI is sent to each CPU that has more than one RT task scheduled on it, it references the root domain's rto_mask, that contains all the CPUs within the root domain that has more than one RT task in the runable state. The problem is, after the IPIs are initiated, the rq->lock is released. This means that the root domain that is associated to the run queue could be freed while the IPIs are going around. Add a sched_get_rd() and a sched_put_rd() that will increment and decrement the root domain's ref count respectively. This way when initiating the IPIs, the scheduler will up the root domain's ref count before releasing the rq->lock, ensuring that the root domain does not go away until the IPI round is complete. Reported-by: Pavan Kondeti <pkondeti@codeaurora.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 4bdced5c9a292 ("sched/rt: Simplify the IPI based RT balancing logic") Link: http://lkml.kernel.org/r/CAEU1=PkiHO35Dzna8EQqNSKW1fr1y1zRQ5y66X117MG06sQtNA@mail.gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-06sched/rt: Use container_of() to get root domain in rto_push_irq_work_func()Steven Rostedt (VMware)
When the rto_push_irq_work_func() is called, it looks at the RT overloaded bitmask in the root domain via the runqueue (rq->rd). The problem is that during CPU up and down, nothing here stops rq->rd from changing between taking the rq->rd->rto_lock and releasing it. That means the lock that is released is not the same lock that was taken. Instead of using this_rq()->rd to get the root domain, as the irq work is part of the root domain, we can simply get the root domain from the irq work that is passed to the routine: container_of(work, struct root_domain, rto_push_work) This keeps the root domain consistent. Reported-by: Pavan Kondeti <pkondeti@codeaurora.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 4bdced5c9a292 ("sched/rt: Simplify the IPI based RT balancing logic") Link: http://lkml.kernel.org/r/CAEU1=PkiHO35Dzna8EQqNSKW1fr1y1zRQ5y66X117MG06sQtNA@mail.gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-01-03Merge branch 'for-mingo' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull RCU updates from Paul E. McKenney: - Updates to use cond_resched() instead of cond_resched_rcu_qs() where feasible (currently everywhere except in kernel/rcu and in kernel/torture.c). Also a couple of fixes to avoid sending IPIs to offline CPUs. - Updates to simplify RCU's dyntick-idle handling. - Updates to remove almost all uses of smp_read_barrier_depends() and read_barrier_depends(). - Miscellaneous fixes. - Torture-test updates. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-12-15sched/rt: Do not pull from current CPU if only one CPU to pullSteven Rostedt
Daniel Wagner reported a crash on the BeagleBone Black SoC. This is a single CPU architecture, and does not have a functional arch_send_call_function_single_ipi() implementation which can crash the kernel if that is called. As it only has one CPU, it shouldn't be called, but if the kernel is compiled for SMP, the push/pull RT scheduling logic now calls it for irq_work if the one CPU is overloaded, it can use that function to call itself and crash the kernel. Ideally, we should disable the SCHED_FEAT(RT_PUSH_IPI) if the system only has a single CPU. But SCHED_FEAT is a constant if sched debugging is turned off. Another fix can also be used, and this should also help with normal SMP machines. That is, do not initiate the pull code if there's only one RT overloaded CPU, and that CPU happens to be the current CPU that is scheduling in a lower priority task. Even on a system with many CPUs, if there's many RT tasks waiting to run on a single CPU, and that CPU schedules in another RT task of lower priority, it will initiate the PULL logic in case there's a higher priority RT task on another CPU that is waiting to run. But if there is no other CPU with waiting RT tasks, it will initiate the RT pull logic on itself (as it still has RT tasks waiting to run). This is a wasted effort. Not only does this help with SMP code where the current CPU is the only one with RT overloaded tasks, it should also solve the issue that Daniel encountered, because it will prevent the PULL logic from executing, as there's only one CPU on the system, and the check added here will cause it to exit the RT pull code. Reported-by: Daniel Wagner <wagi@monom.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-rt-users <linux-rt-users@vger.kernel.org> Cc: stable@vger.kernel.org Fixes: 4bdced5c9 ("sched/rt: Simplify the IPI based RT balancing logic") Link: http://lkml.kernel.org/r/20171202130454.4cbbfe8d@vmware.local.home Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-28sched: Stop switched_to_rt() from sending IPIs to offline CPUsPaul E. McKenney
The rcutorture test suite occasionally provokes a splat due to invoking rt_mutex_lock() which needs to boost the priority of a task currently sitting on a runqueue that belongs to an offline CPU: WARNING: CPU: 0 PID: 12 at /home/paulmck/public_git/linux-rcu/arch/x86/kernel/smp.c:128 native_smp_send_reschedule+0x37/0x40 Modules linked in: CPU: 0 PID: 12 Comm: rcub/7 Not tainted 4.14.0-rc4+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 task: ffff9ed3de5f8cc0 task.stack: ffffbbf80012c000 RIP: 0010:native_smp_send_reschedule+0x37/0x40 RSP: 0018:ffffbbf80012fd10 EFLAGS: 00010082 RAX: 000000000000002f RBX: ffff9ed3dd9cb300 RCX: 0000000000000004 RDX: 0000000080000004 RSI: 0000000000000086 RDI: 00000000ffffffff RBP: ffffbbf80012fd10 R08: 000000000009da7a R09: 0000000000007b9d R10: 0000000000000001 R11: ffffffffbb57c2cd R12: 000000000000000d R13: ffff9ed3de5f8cc0 R14: 0000000000000061 R15: ffff9ed3ded59200 FS: 0000000000000000(0000) GS:ffff9ed3dea00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000080686f0 CR3: 000000001b9e0000 CR4: 00000000000006f0 Call Trace: resched_curr+0x61/0xd0 switched_to_rt+0x8f/0xa0 rt_mutex_setprio+0x25c/0x410 task_blocks_on_rt_mutex+0x1b3/0x1f0 rt_mutex_slowlock+0xa9/0x1e0 rt_mutex_lock+0x29/0x30 rcu_boost_kthread+0x127/0x3c0 kthread+0x104/0x140 ? rcu_report_unblock_qs_rnp+0x90/0x90 ? kthread_create_on_node+0x40/0x40 ret_from_fork+0x22/0x30 Code: f0 00 0f 92 c0 84 c0 74 14 48 8b 05 34 74 c5 00 be fd 00 00 00 ff 90 a0 00 00 00 5d c3 89 fe 48 c7 c7 a0 c6 fc b9 e8 d5 b5 06 00 <0f> ff 5d c3 0f 1f 44 00 00 8b 05 a2 d1 13 02 85 c0 75 38 55 48 But the target task's priority has already been adjusted, so the only purpose of switched_to_rt() invoking resched_curr() is to wake up the CPU running some task that needs to be preempted by the boosted task. But the CPU is offline, which presumably means that the task must be migrated to some other CPU, and that this other CPU will undertake any needed preemption at the time of migration. Because the runqueue lock is held when resched_curr() is invoked, we know that the boosted task cannot go anywhere, so it is not necessary to invoke resched_curr() in this particular case. This commit therefore makes switched_to_rt() refrain from invoking resched_curr() when the target CPU is offline. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org>
2017-11-15Merge branch 'for-4.15' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: "Cgroup2 cpu controller support is finally merged. - Basic cpu statistics support to allow monitoring by default without the CPU controller enabled. - cgroup2 cpu controller support. - /sys/kernel/cgroup files to help dealing with new / optional features" * 'for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: export list of cgroups v2 features using sysfs cgroup: export list of delegatable control files using sysfs cgroup: mark @cgrp __maybe_unused in cpu_stat_show() MAINTAINERS: relocate cpuset.c cgroup, sched: Move basic cpu stats from cgroup.stat to cpu.stat sched: Implement interface for cgroup unified hierarchy sched: Misc preps for cgroup unified hierarchy interface sched/cputime: Add dummy cputime_adjust() implementation for CONFIG_VIRT_CPU_ACCOUNTING_NATIVE cgroup: statically initialize init_css_set->dfl_cgrp cgroup: Implement cgroup2 basic CPU usage accounting cpuacct: Introduce cgroup_account_cputime[_field]() sched/cputime: Expose cputime_adjust()
2017-11-08Merge branch 'linus' into sched/core, to pick up fixesIngo Molnar
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-10sched/rt: Simplify the IPI based RT balancing logicSteven Rostedt (Red Hat)
When a CPU lowers its priority (schedules out a high priority task for a lower priority one), a check is made to see if any other CPU has overloaded RT tasks (more than one). It checks the rto_mask to determine this and if so it will request to pull one of those tasks to itself if the non running RT task is of higher priority than the new priority of the next task to run on the current CPU. When we deal with large number of CPUs, the original pull logic suffered from large lock contention on a single CPU run queue, which caused a huge latency across all CPUs. This was caused by only having one CPU having overloaded RT tasks and a bunch of other CPUs lowering their priority. To solve this issue, commit: b6366f048e0c ("sched/rt: Use IPI to trigger RT task push migration instead of pulling") changed the way to request a pull. Instead of grabbing the lock of the overloaded CPU's runqueue, it simply sent an IPI to that CPU to do the work. Although the IPI logic worked very well in removing the large latency build up, it still could suffer from a large number of IPIs being sent to a single CPU. On a 80 CPU box, I measured over 200us of processing IPIs. Worse yet, when I tested this on a 120 CPU box, with a stress test that had lots of RT tasks scheduling on all CPUs, it actually triggered the hard lockup detector! One CPU had so many IPIs sent to it, and due to the restart mechanism that is triggered when the source run queue has a priority status change, the CPU spent minutes! processing the IPIs. Thinking about this further, I realized there's no reason for each run queue to send its own IPI. As all CPUs with overloaded tasks must be scanned regardless if there's one or many CPUs lowering their priority, because there's no current way to find the CPU with the highest priority task that can schedule to one of these CPUs, there really only needs to be one IPI being sent around at a time. This greatly simplifies the code! The new approach is to have each root domain have its own irq work, as the rto_mask is per root domain. The root domain has the following fields attached to it: rto_push_work - the irq work to process each CPU set in rto_mask rto_lock - the lock to protect some of the other rto fields rto_loop_start - an atomic that keeps contention down on rto_lock the first CPU scheduling in a lower priority task is the one to kick off the process. rto_loop_next - an atomic that gets incremented for each CPU that schedules in a lower priority task. rto_loop - a variable protected by rto_lock that is used to compare against rto_loop_next rto_cpu - The cpu to send the next IPI to, also protected by the rto_lock. When a CPU schedules in a lower priority task and wants to make sure overloaded CPUs know about it. It increments the rto_loop_next. Then it atomically sets rto_loop_start with a cmpxchg. If the old value is not "0", then it is done, as another CPU is kicking off the IPI loop. If the old value is "0", then it will take the rto_lock to synchronize with a possible IPI being sent around to the overloaded CPUs. If rto_cpu is greater than or equal to nr_cpu_ids, then there's either no IPI being sent around, or one is about to finish. Then rto_cpu is set to the first CPU in rto_mask and an IPI is sent to that CPU. If there's no CPUs set in rto_mask, then there's nothing to be done. When the CPU receives the IPI, it will first try to push any RT tasks that is queued on the CPU but can't run because a higher priority RT task is currently running on that CPU. Then it takes the rto_lock and looks for the next CPU in the rto_mask. If it finds one, it simply sends an IPI to that CPU and the process continues. If there's no more CPUs in the rto_mask, then rto_loop is compared with rto_loop_next. If they match, everything is done and the process is over. If they do not match, then a CPU scheduled in a lower priority task as the IPI was being passed around, and the process needs to start again. The first CPU in rto_mask is sent the IPI. This change removes this duplication of work in the IPI logic, and greatly lowers the latency caused by the IPIs. This removed the lockup happening on the 120 CPU machine. It also simplifies the code tremendously. What else could anyone ask for? Thanks to Peter Zijlstra for simplifying the rto_loop_start atomic logic and supplying me with the rto_start_trylock() and rto_start_unlock() helper functions. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Clark Williams <williams@redhat.com> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Scott Wood <swood@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170424114732.1aac6dc4@gandalf.local.home Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-25cpuacct: Introduce cgroup_account_cputime[_field]()Tejun Heo
Introduce cgroup_account_cputime[_field]() which wrap cpuacct_charge() and cgroup_account_field(). This doesn't introduce any functional changes and will be used to add cgroup basic resource accounting. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com>
2017-08-01sched: cpufreq: Allow remote cpufreq callbacksViresh Kumar
With Android UI and benchmarks the latency of cpufreq response to certain scheduling events can become very critical. Currently, callbacks into cpufreq governors are only made from the scheduler if the target CPU of the event is the same as the current CPU. This means there are certain situations where a target CPU may not run the cpufreq governor for some time. One testcase to show this behavior is where a task starts running on CPU0, then a new task is also spawned on CPU0 by a task on CPU1. If the system is configured such that the new tasks should receive maximum demand initially, this should result in CPU0 increasing frequency immediately. But because of the above mentioned limitation though, this does not occur. This patch updates the scheduler core to call the cpufreq callbacks for remote CPUs as well. The schedutil, ondemand and conservative governors are updated to process cpufreq utilization update hooks called for remote CPUs where the remote CPU is managed by the cpufreq policy of the local CPU. The intel_pstate driver is updated to always reject remote callbacks. This is tested with couple of usecases (Android: hackbench, recentfling, galleryfling, vellamo, Ubuntu: hackbench) on ARM hikey board (64 bit octa-core, single policy). Only galleryfling showed minor improvements, while others didn't had much deviation. The reason being that this patch only targets a corner case, where following are required to be true to improve performance and that doesn't happen too often with these tests: - Task is migrated to another CPU. - The task has high demand, and should take the target CPU to higher OPPs. - And the target CPU doesn't call into the cpufreq governor until the next tick. Based on initial work from Steve Muckle. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Saravana Kannan <skannan@codeaurora.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-06-23sched/rt: Move RT related code from sched/core.c to sched/rt.cNicolas Pitre
This helps making sched/core.c smaller and hopefully easier to understand and maintain. Signed-off-by: Nicolas Pitre <nico@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170621182203.30626-3-nicolas.pitre@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-05-23sched/rt: Minimize rq->lock contention in do_sched_rt_period_timer()Dave Kleikamp
With CONFIG_RT_GROUP_SCHED=y, do_sched_rt_period_timer() sequentially takes each CPU's rq->lock. On a large, busy system, the cumulative time it takes to acquire each lock can be excessive, even triggering a watchdog timeout. If rt_rq->rt_time and rt_rq->rt_nr_running are both zero, this function does nothing while holding the lock, so don't bother taking it at all. Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/a767637b-df85-912f-ba69-c90ee00a3fb6@oracle.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-05-23sched/rt: Remove unnecessary condition in push_rt_task()Byungchul Park
pick_next_pushable_task(rq) has BUG_ON(rq_cpu != task_cpu(task)) when it returns a task other than NULL, which means that task_cpu(task) must be rq->cpu. So if task == next_task, then task_cpu(next_task) must be rq->cpu as well. Remove the redundant condition and make the code simpler. This way one unnecessary branch and two LOAD operations can be avoided. Signed-off-by: Byungchul Park <byungchul.park@lge.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by: Juri Lelli <juri.lelli@arm.com> Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: <kernel-team@lge.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1494551143-22219-1-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-16sched/rt: Add comments describing the RT IPI pull methodSteven Rostedt (VMware)
While looking into optimizations for the RT scheduler IPI logic, I realized that the comments are lacking to describe it efficiently. It deserves a lengthy description describing its design. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Clark Williams <williams@redhat.com> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170228155030.30c69068@gandalf.local.home [ Small typographical edits. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02sched/core: Remove the tsk_nr_cpus_allowed() wrapperIngo Molnar
tsk_nr_cpus_allowed() too is a pretty pointless wrapper that is not used consistently and which makes the code both harder to read and longer as well. So remove it - this also shrinks <linux/sched.h> a bit. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02sched/core: Remove the tsk_cpus_allowed() wrapperIngo Molnar
So the original intention of tsk_cpus_allowed() was to 'future-proof' the field - but it's pretty ineffectual at that, because half of the code uses ->cpus_allowed directly ... Also, the wrapper makes the code longer than the original expression! So just get rid of it. This also shrinks <linux/sched.h> a bit. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-20Merge branch 'sched-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: "The main changes in this (fairly busy) cycle were: - There was a class of scheduler bugs related to forgetting to update the rq-clock timestamp which can cause weird and hard to debug problems, so there's a new debug facility for this: which uncovered a whole lot of bugs which convinced us that we want to keep the debug facility. (Peter Zijlstra, Matt Fleming) - Various cputime related updates: eliminate cputime and use u64 nanoseconds directly, simplify and improve the arch interfaces, implement delayed accounting more widely, etc. - (Frederic Weisbecker) - Move code around for better structure plus cleanups (Ingo Molnar) - Move IO schedule accounting deeper into the scheduler plus related changes to improve the situation (Tejun Heo) - ... plus a round of sched/rt and sched/deadline fixes, plus other fixes, updats and cleanups" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (85 commits) sched/core: Remove unlikely() annotation from sched_move_task() sched/autogroup: Rename auto_group.[ch] to autogroup.[ch] sched/topology: Split out scheduler topology code from core.c into topology.c sched/core: Remove unnecessary #include headers sched/rq_clock: Consolidate the ordering of the rq_clock methods delayacct: Include <uapi/linux/taskstats.h> sched/core: Clean up comments sched/rt: Show the 'sched_rr_timeslice' SCHED_RR timeslice tuning knob in milliseconds sched/clock: Add dummy clear_sched_clock_stable() stub function sched/cputime: Remove generic asm headers sched/cputime: Remove unused nsec_to_cputime() s390, sched/cputime: Remove unused cputime definitions powerpc, sched/cputime: Remove unused cputime definitions s390, sched/cputime: Make arch_cpu_idle_time() to return nsecs ia64, sched/cputime: Remove unused cputime definitions ia64: Convert vtime to use nsec units directly ia64, sched/cputime: Move the nsecs based cputime headers to the last arch using it sched/cputime: Remove jiffies based cputime sched/cputime, vtime: Return nsecs instead of cputime_t to account sched/cputime: Complete nsec conversion of tick based accounting ...
2017-02-01sched/rt: Show the 'sched_rr_timeslice' SCHED_RR timeslice tuning knob in ↵Shile Zhang
milliseconds We added the 'sched_rr_timeslice_ms' SCHED_RR tuning knob in this commit: ce0dbbbb30ae ("sched/rt: Add a tuning knob to allow changing SCHED_RR timeslice") ... which name suggests to users that it's in milliseconds, while in reality it's being set in milliseconds but the result is shown in jiffies. This is obviously confusing when HZ is not 1000, it makes it appear like the value set failed, such as HZ=100: root# echo 100 > /proc/sys/kernel/sched_rr_timeslice_ms root# cat /proc/sys/kernel/sched_rr_timeslice_ms 10 Fix this to be milliseconds all around. Signed-off-by: Shile Zhang <shile.zhang@nokia.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1485612049-20923-1-git-send-email-shile.zhang@nokia.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-01-30sched/rt: Add a missing rescheduling pointSebastian Andrzej Siewior
Since the change in commit: fd7a4bed1835 ("sched, rt: Convert switched_{from, to}_rt() / prio_changed_rt() to balance callbacks") ... we don't reschedule a task under certain circumstances: Lets say task-A, SCHED_OTHER, is running on CPU0 (and it may run only on CPU0) and holds a PI lock. This task is removed from the CPU because it used up its time slice and another SCHED_OTHER task is running. Task-B on CPU1 runs at RT priority and asks for the lock owned by task-A. This results in a priority boost for task-A. Task-B goes to sleep until the lock has been made available. Task-A is already runnable (but not active), so it receives no wake up. The reality now is that task-A gets on the CPU once the scheduler decides to remove the current task despite the fact that a high priority task is enqueued and waiting. This may take a long time. The desired behaviour is that CPU0 immediately reschedules after the priority boost which made task-A the task with the lowest priority. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: fd7a4bed1835 ("sched, rt: Convert switched_{from, to}_rt() prio_changed_rt() to balance callbacks") Link: http://lkml.kernel.org/r/20170124144006.29821-1-bigeasy@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-01-27timers: Omit POSIX timer stuff from task_struct when disabledNicolas Pitre
When CONFIG_POSIX_TIMERS is disabled, it is preferable to remove related structures from struct task_struct and struct signal_struct as they won't contain anything useful and shouldn't be relied upon by mistake. Code still referencing those structures is also disabled here. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
2017-01-14sched/core: Add wrappers for lockdep_(un)pin_lock()Matt Fleming
In preparation for adding diagnostic checks to catch missing calls to update_rq_clock(), provide wrappers for (re)pinning and unpinning rq->lock. Because the pending diagnostic checks allow state to be maintained in rq_flags across pin contexts, swap the 'struct pin_cookie' arguments for 'struct rq_flags *'. Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Byungchul Park <byungchul.park@lge.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luca Abeni <luca.abeni@unitn.it> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Galbraith <efault@gmx.de> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Rik van Riel <riel@redhat.com> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Cc: Yuyang Du <yuyang.du@intel.com> Link: http://lkml.kernel.org/r/20160921133813.31976-5-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-16cpufreq / sched: Pass runqueue pointer to cpufreq_update_util()Rafael J. Wysocki
All of the callers of cpufreq_update_util() pass rq_clock(rq) to it as the time argument and some of them check whether or not cpu_of(rq) is equal to smp_processor_id() before calling it, so rework it to take a runqueue pointer as the argument and move the rq_clock(rq) evaluation into it. Additionally, provide a wrapper checking cpu_of(rq) against smp_processor_id() for the cpufreq_update_util() callers that need it. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-08-16cpufreq / sched: Pass flags to cpufreq_update_util()Rafael J. Wysocki
It is useful to know the reason why cpufreq_update_util() has just been called and that can be passed as flags to cpufreq_update_util() and to the ->func() callback in struct update_util_data. However, doing that in addition to passing the util and max arguments they already take would be clumsy, so avoid it. Instead, use the observation that the schedutil governor is part of the scheduler proper, so it can access scheduler data directly. This allows the util and max arguments of cpufreq_update_util() and the ->func() callback in struct update_util_data to be replaced with a flags one, but schedutil has to be modified to follow. Thus make the schedutil governor obtain the CFS utilization information from the scheduler and use the "RT" and "DL" flags instead of the special utilization value of ULONG_MAX to track updates from the RT and DL sched classes. Make it non-modular too to avoid having to export scheduler variables to modules at large. Next, update all of the other users of cpufreq_update_util() and the ->func() callback in struct update_util_data accordingly. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-05-12sched/core: Provide a tsk_nr_cpus_allowed() helperThomas Gleixner
tsk_nr_cpus_allowed() is an accessor for task->nr_cpus_allowed which allows us to change the representation of ->nr_cpus_allowed if required. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/1462969411-17735-2-git-send-email-bigeasy@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-12Merge branch 'sched/urgent' into sched/core to pick up fixesIngo Molnar
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-10sched/rt, sched/dl: Don't push if task's scheduling class was changedXunlei Pang
We got this warning: WARNING: CPU: 1 PID: 2468 at kernel/sched/core.c:1161 set_task_cpu+0x1af/0x1c0 [...] Call Trace: dump_stack+0x63/0x87 __warn+0xd1/0xf0 warn_slowpath_null+0x1d/0x20 set_task_cpu+0x1af/0x1c0 push_dl_task.part.34+0xea/0x180 push_dl_tasks+0x17/0x30 __balance_callback+0x45/0x5c __sched_setscheduler+0x906/0xb90 SyS_sched_setattr+0x150/0x190 do_syscall_64+0x62/0x110 entry_SYSCALL64_slow_path+0x25/0x25 This corresponds to: WARN_ON_ONCE(p->state == TASK_RUNNING && p->sched_class == &fair_sched_class && (p->on_rq && !task_on_rq_migrating(p))) It happens because in find_lock_later_rq(), the task whose scheduling class was changed to fair class is still pushed away as if it were a deadline task ... So, check in find_lock_later_rq() after double_lock_balance(), if the scheduling class of the deadline task was changed, break and retry. Apply the same logic to RT tasks. Signed-off-by: Xunlei Pang <xlpang@redhat.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Juri Lelli <juri.lelli@arm.com> Link: http://lkml.kernel.org/r/1462767091-1215-1-git-send-email-xlpang@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-05locking/lockdep, sched/core: Implement a better lock pinning schemePeter Zijlstra
The problem with the existing lock pinning is that each pin is of value 1; this mean you can simply unpin if you know its pinned, without having any extra information. This scheme generates a random (16 bit) cookie for each pin and requires this same cookie to unpin. This means you have to keep the cookie in context. No objsize difference for !LOCKDEP kernels. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28sched/cpufreq: Optimize cpufreq update kicker to avoid update multiple timesWanpeng Li
Sometimes delta_exec is 0 due to update_curr() is called multiple times, this is captured by: u64 delta_exec = rq_clock_task(rq) - curr->se.exec_start; This patch optimizes the cpufreq update kicker by bailing out when nothing changed, it will benefit the upcoming schedutil, since otherwise it will (over)react to the special util/max combination. Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1461316044-9520-1-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-16Merge tag 'pm+acpi-4.6-rc1-1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management and ACPI updates from Rafael Wysocki: "This time the majority of changes go into cpufreq and they are significant. First off, the way CPU frequency updates are triggered is different now. Instead of having to set up and manage a deferrable timer for each CPU in the system to evaluate and possibly change its frequency periodically, cpufreq governors set up callbacks to be invoked by the scheduler on a regular basis (basically on utilization updates). The "old" governors, "ondemand" and "conservative", still do all of their work in process context (although that is triggered by the scheduler now), but intel_pstate does it all in the callback invoked by the scheduler with no need for any additional asynchronous processing. Of course, this eliminates the overhead related to the management of all those timers, but also it allows the cpufreq governor code to be simplified quite a bit. On top of that, the common code and data structures used by the "ondemand" and "conservative" governors are cleaned up and made more straightforward and some long-standing and quite annoying problems are addressed. In particular, the handling of governor sysfs attributes is modified and the related locking becomes more fine grained which allows some concurrency problems to be avoided (particularly deadlocks with the core cpufreq code). In principle, the new mechanism for triggering frequency updates allows utilization information to be passed from the scheduler to cpufreq. Although the current code doesn't make use of it, in the works is a new cpufreq governor that will make decisions based on the scheduler's utilization data. That should allow the scheduler and cpufreq to work more closely together in the long run. In addition to the core and governor changes, cpufreq drivers are updated too. Fixes and optimizations go into intel_pstate, the cpufreq-dt driver is updated on top of some modification in the Operating Performance Points (OPP) framework and there are fixes and other updates in the powernv cpufreq driver. Apart from the cpufreq updates there is some new ACPICA material, including a fix for a problem introduced by previous ACPICA updates, and some less significant changes in the ACPI code, like CPPC code optimizations, ACPI processor driver cleanups and support for loading ACPI tables from initrd. Also updated are the generic power domains framework, the Intel RAPL power capping driver and the turbostat utility and we have a bunch of traditional assorted fixes and cleanups. Specifics: - Redesign of cpufreq governors and the intel_pstate driver to make them use callbacks invoked by the scheduler to trigger CPU frequency evaluation instead of using per-CPU deferrable timers for that purpose (Rafael Wysocki). - Reorganization and cleanup of cpufreq governor code to make it more straightforward and fix some concurrency problems in it (Rafael Wysocki, Viresh Kumar). - Cleanup and improvements of locking in the cpufreq core (Viresh Kumar). - Assorted cleanups in the cpufreq core (Rafael Wysocki, Viresh Kumar, Eric Biggers). - intel_pstate driver updates including fixes, optimizations and a modification to make it enable enable hardware-coordinated P-state selection (HWP) by default if supported by the processor (Philippe Longepe, Srinivas Pandruvada, Rafael Wysocki, Viresh Kumar, Felipe Franciosi). - Operating Performance Points (OPP) framework updates to improve its handling of voltage regulators and device clocks and updates of the cpufreq-dt driver on top of that (Viresh Kumar, Jon Hunter). - Updates of the powernv cpufreq driver to fix initialization and cleanup problems in it and correct its worker thread handling with respect to CPU offline, new powernv_throttle tracepoint (Shilpasri Bhat). - ACPI cpufreq driver optimization and cleanup (Rafael Wysocki). - ACPICA updates including one fix for a regression introduced by previos changes in the ACPICA code (Bob Moore, Lv Zheng, David Box, Colin Ian King). - Support for installing ACPI tables from initrd (Lv Zheng). - Optimizations of the ACPI CPPC code (Prashanth Prakash, Ashwin Chaugule). - Support for _HID(ACPI0010) devices (ACPI processor containers) and ACPI processor driver cleanups (Sudeep Holla). - Support for ACPI-based enumeration of the AMBA bus (Graeme Gregory, Aleksey Makarov). - Modification of the ACPI PCI IRQ management code to make it treat 255 in the Interrupt Line register as "not connected" on x86 (as per the specification) and avoid attempts to use that value as a valid interrupt vector (Chen Fan). - ACPI APEI fixes related to resource leaks (Josh Hunt). - Removal of modularity from a few ACPI drivers (BGRT, GHES, intel_pmic_crc) that cannot be built as modules in practice (Paul Gortmaker). - PNP framework update to make it treat ACPI_RESOURCE_TYPE_SERIAL_BUS as a valid resource type (Harb Abdulhamid). - New device ID (future AMD I2C controller) in the ACPI driver for AMD SoCs (APD) and in the designware I2C driver (Xiangliang Yu). - Assorted ACPI cleanups (Colin Ian King, Kaiyen Chang, Oleg Drokin). - cpuidle menu governor optimization to avoid a square root computation in it (Rasmus Villemoes). - Fix for potential use-after-free in the generic device properties framework (Heikki Krogerus). - Updates of the generic power domains (genpd) framework including support for multiple power states of a domain, fixes and debugfs output improvements (Axel Haslam, Jon Hunter, Laurent Pinchart, Geert Uytterhoeven). - Intel RAPL power capping driver updates to reduce IPI overhead in it (Jacob Pan). - System suspend/hibernation code cleanups (Eric Biggers, Saurabh Sengar). - Year 2038 fix for the process freezer (Abhilash Jindal). - turbostat utility updates including new features (decoding of more registers and CPUID fields, sub-second intervals support, GFX MHz and RC6 printout, --out command line option), fixes (syscall jitter detection and workaround, reductioin of the number of syscalls made, fixes related to Xeon x200 processors, compiler warning fixes) and cleanups (Len Brown, Hubert Chrzaniuk, Chen Yu)" * tag 'pm+acpi-4.6-rc1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (182 commits) tools/power turbostat: bugfix: TDP MSRs print bits fixing tools/power turbostat: correct output for MSR_NHM_SNB_PKG_CST_CFG_CTL dump tools/power turbostat: call __cpuid() instead of __get_cpuid() tools/power turbostat: indicate SMX and SGX support tools/power turbostat: detect and work around syscall jitter tools/power turbostat: show GFX%rc6 tools/power turbostat: show GFXMHz tools/power turbostat: show IRQs per CPU tools/power turbostat: make fewer systems calls tools/power turbostat: fix compiler warnings tools/power turbostat: add --out option for saving output in a file tools/power turbostat: re-name "%Busy" field to "Busy%" tools/power turbostat: Intel Xeon x200: fix turbo-ratio decoding tools/power turbostat: Intel Xeon x200: fix erroneous bclk value tools/power turbostat: allow sub-sec intervals ACPI / APEI: ERST: Fixed leaked resources in erst_init ACPI / APEI: Fix leaked resources intel_pstate: Do not skip samples partially intel_pstate: Remove freq calculation from intel_pstate_calc_busy() intel_pstate: Move intel_pstate_calc_busy() into get_target_pstate_use_performance() ...
2016-03-14Merge branch 'timers-nohz-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull NOHZ updates from Ingo Molnar: "NOHZ enhancements, by Frederic Weisbecker, which reorganizes/refactors the NOHZ 'can the tick be stopped?' infrastructure and related code to be data driven, and harmonizes the naming and handling of all the various properties" [ This makes the ugly "fetch_or()" macro that the scheduler used internally a new generic helper, and does a bad job at it. I'm pulling it, but I've asked Ingo and Frederic to get this fixed up ] * 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched-clock: Migrate to use new tick dependency mask model posix-cpu-timers: Migrate to use new tick dependency mask model sched: Migrate sched to use new tick dependency mask model sched: Account rr tasks perf: Migrate perf to use new tick dependency mask model nohz: Use enum code for tick stop failure tracing message nohz: New tick dependency mask nohz: Implement wide kick on top of irq work atomic: Export fetch_or()
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-09 02:04:17 +0000