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* Merge tag 'pm-4.7-rc1' of ↵Linus Torvalds2016-05-164-11/+576
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management updates from Rafael Wysocki: "The majority of changes go into the cpufreq subsystem this time. To me, quite obviously, the biggest ticket item is the new "schedutil" governor. Interestingly enough, it's the first new cpufreq governor since the beginning of the git era (except for some out-of-the-tree ones). There are two main differences between it and the existing governors. First, it uses the information provided by the scheduler directly for making its decisions, so it doesn't have to track anything by itself. Second, it can invoke drivers (supporting that feature) to adjust CPU performance right away without having to spawn work items to be executed in process context or similar. Currently, the acpi-cpufreq driver is the only one supporting that mode of operation, but then it is used on a large number of systems. The "schedutil" governor as included here is very simple and mostly regarded as a foundation for future work on the integration of the scheduler with CPU power management (in fact, there is work in progress on top of it already). Nevertheless it works and the preliminary results obtained with it are encouraging. There also is some consolidation of CPU frequency management for ARM platforms that can add their machine IDs the the new stub dt-platdev driver now and that will take care of creating the requisite platform device for cpufreq-dt, so it is not necessary to do that in platform code any more. Several ARM platforms are switched over to using this generic mechanism. In addition to that, the intel_pstate driver is now going to respect CPU frequency limits set by the platform firmware (or a BMC) and provided via the ACPI _PPC object. The devfreq subsystem is getting a new "passive" governor for SoCs subsystems that will depend on somebody else to manage their voltage rails and its support for Samsung Exynos SoCs is consolidated. The rest is support for new hardware (Intel Broxton support in intel_idle for one example), bug fixes, optimizations and cleanups in a number of places. Specifics: - New cpufreq "schedutil" governor (making decisions based on CPU utilization information provided by the scheduler and capable of switching CPU frequencies right away if the underlying driver supports that) and support for fast frequency switching in the acpi-cpufreq driver (Rafael Wysocki) - Consolidation of CPU frequency management on ARM platforms allowing them to get rid of some platform-specific boilerplate code if they are going to use the cpufreq-dt driver (Viresh Kumar, Finley Xiao, Marc Gonzalez) - Support for ACPI _PPC and CPU frequency limits in the intel_pstate driver (Srinivas Pandruvada) - Fixes and cleanups in the cpufreq core and generic governor code (Rafael Wysocki, Sai Gurrappadi) - intel_pstate driver optimizations and cleanups (Rafael Wysocki, Philippe Longepe, Chen Yu, Joe Perches) - cpufreq powernv driver fixes and cleanups (Akshay Adiga, Shilpasri Bhat) - cpufreq qoriq driver fixes and cleanups (Jia Hongtao) - ACPI cpufreq driver cleanups (Viresh Kumar) - Assorted cpufreq driver updates (Ashwin Chaugule, Geliang Tang, Javier Martinez Canillas, Paul Gortmaker, Sudeep Holla) - Assorted cpufreq fixes and cleanups (Joe Perches, Arnd Bergmann) - Fixes and cleanups in the OPP (Operating Performance Points) framework, mostly related to OPP sharing, and reorganization of OF-dependent code in it (Viresh Kumar, Arnd Bergmann, Sudeep Holla) - New "passive" governor for devfreq (for SoC subsystems that will rely on someone else for the management of their power resources) and consolidation of devfreq support for Exynos platforms, coding style and typo fixes for devfreq (Chanwoo Choi, MyungJoo Ham) - PM core fixes and cleanups, mostly to make it work better with the generic power domains (genpd) framework, and updates for that framework (Ulf Hansson, Thierry Reding, Colin Ian King) - Intel Broxton support for the intel_idle driver (Len Brown) - cpuidle core optimization and fix (Daniel Lezcano, Dave Gerlach) - ARM cpuidle cleanups (Jisheng Zhang) - Intel Kabylake support for the RAPL power capping driver (Jacob Pan) - AVS (Adaptive Voltage Switching) rockchip-io driver update (Heiko Stuebner) - Updates for the cpupower tool (Arjun Sreedharan, Colin Ian King, Mattia Dongili, Thomas Renninger)" * tag 'pm-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (112 commits) intel_pstate: Clean up get_target_pstate_use_performance() intel_pstate: Use sample.core_avg_perf in get_avg_pstate() intel_pstate: Clarify average performance computation intel_pstate: Avoid unnecessary synchronize_sched() during initialization cpufreq: schedutil: Make default depend on CONFIG_SMP cpufreq: powernv: del_timer_sync when global and local pstate are equal cpufreq: powernv: Move smp_call_function_any() out of irq safe block intel_pstate: Clean up intel_pstate_get() cpufreq: schedutil: Make it depend on CONFIG_SMP cpufreq: governor: Fix handling of special cases in dbs_update() PM / OPP: Move CONFIG_OF dependent code in a separate file cpufreq: intel_pstate: Ignore _PPC processing under HWP cpufreq: arm_big_little: use generic OPP functions for {init, free}_opp_table PM / OPP: add non-OF versions of dev_pm_opp_{cpumask_, }remove_table cpufreq: tango: Use generic platdev driver PM / OPP: pass cpumask by reference cpufreq: Fix GOV_LIMITS handling for the userspace governor cpupower: fix potential memory leak PM / devfreq: style/typo fixes PM / devfreq: exynos: Add the detailed correlation for Exynos5422 bus ..
| * Merge branch 'pm-cpufreq'Rafael J. Wysocki2016-05-164-11/+576
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * pm-cpufreq: (63 commits) intel_pstate: Clean up get_target_pstate_use_performance() intel_pstate: Use sample.core_avg_perf in get_avg_pstate() intel_pstate: Clarify average performance computation intel_pstate: Avoid unnecessary synchronize_sched() during initialization cpufreq: schedutil: Make default depend on CONFIG_SMP cpufreq: powernv: del_timer_sync when global and local pstate are equal cpufreq: powernv: Move smp_call_function_any() out of irq safe block intel_pstate: Clean up intel_pstate_get() cpufreq: schedutil: Make it depend on CONFIG_SMP cpufreq: governor: Fix handling of special cases in dbs_update() cpufreq: intel_pstate: Ignore _PPC processing under HWP cpufreq: arm_big_little: use generic OPP functions for {init, free}_opp_table cpufreq: tango: Use generic platdev driver cpufreq: Fix GOV_LIMITS handling for the userspace governor cpufreq: mvebu: Move cpufreq code into drivers/cpufreq/ cpufreq: dt: Kill platform-data mvebu: Use dev_pm_opp_set_sharing_cpus() to mark OPP tables as shared cpufreq: dt: Identify cpu-sharing for platforms without operating-points-v2 cpufreq: governor: Change confusing struct field and variable names cpufreq: intel_pstate: Enable PPC enforcement for servers ...
| | * Merge back earlier cpufreq material for v4.7.Rafael J. Wysocki2016-04-284-11/+576
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| | | * cpufreq: Call cpufreq_disable_fast_switch() in sugov_exit()Rafael J. Wysocki2016-04-081-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Due to differences in the cpufreq core's handling of runtime CPU offline and nonboot CPUs disabling during system suspend-to-RAM, fast frequency switching gets disabled after a suspend-to-RAM and resume cycle on all of the nonboot CPUs. To prevent that from happening, move the invocation of cpufreq_disable_fast_switch() from cpufreq_exit_governor() to sugov_exit(), as the schedutil governor is the only user of fast frequency switching today anyway. That simply prevents cpufreq_disable_fast_switch() from being called without invoking the ->governor callback for the CPUFREQ_GOV_POLICY_EXIT event (which happens during system suspend now). Fixes: b7898fda5bc7 (cpufreq: Support for fast frequency switching) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
| | | * cpufreq: schedutil: New governor based on scheduler utilization dataRafael J. Wysocki2016-04-023-0/+537
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a new cpufreq scaling governor, called "schedutil", that uses scheduler-provided CPU utilization information as input for making its decisions. Doing that is possible after commit 34e2c555f3e1 (cpufreq: Add mechanism for registering utilization update callbacks) that introduced cpufreq_update_util() called by the scheduler on utilization changes (from CFS) and RT/DL task status updates. In particular, CPU frequency scaling decisions may be based on the the utilization data passed to cpufreq_update_util() by CFS. The new governor is relatively simple. The frequency selection formula used by it depends on whether or not the utilization is frequency-invariant. In the frequency-invariant case the new CPU frequency is given by next_freq = 1.25 * max_freq * util / max where util and max are the last two arguments of cpufreq_update_util(). In turn, if util is not frequency-invariant, the maximum frequency in the above formula is replaced with the current frequency of the CPU: next_freq = 1.25 * curr_freq * util / max The coefficient 1.25 corresponds to the frequency tipping point at (util / max) = 0.8. All of the computations are carried out in the utilization update handlers provided by the new governor. One of those handlers is used for cpufreq policies shared between multiple CPUs and the other one is for policies with one CPU only (and therefore it doesn't need to use any extra synchronization means). The governor supports fast frequency switching if that is supported by the cpufreq driver in use and possible for the given policy. In the fast switching case, all operations of the governor take place in its utilization update handlers. If fast switching cannot be used, the frequency switch operations are carried out with the help of a work item which only calls __cpufreq_driver_target() (under a mutex) to trigger a frequency update (to a value already computed beforehand in one of the utilization update handlers). Currently, the governor treats all of the RT and DL tasks as "unknown utilization" and sets the frequency to the allowed maximum when updated from the RT or DL sched classes. That heavy-handed approach should be replaced with something more subtle and specifically targeted at RT and DL tasks. The governor shares some tunables management code with the "ondemand" and "conservative" governors and uses some common definitions from cpufreq_governor.h, but apart from that it is stand-alone. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
| | | * cpufreq: sched: Helpers to add and remove update_util hooksRafael J. Wysocki2016-04-021-11/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Replace the single helper for adding and removing cpufreq utilization update hooks, cpufreq_set_update_util_data(), with a pair of helpers, cpufreq_add_update_util_hook() and cpufreq_remove_update_util_hook(), and modify the users of cpufreq_set_update_util_data() accordingly. With the new helpers, the code using them doesn't need to worry about the internals of struct update_util_data and in particular it doesn't need to worry about populating the func field in it properly upfront. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
* | | | sched/core: Provide a tsk_nr_cpus_allowed() helperThomas Gleixner2016-05-123-27/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | | sched/core: Use tsk_cpus_allowed() instead of accessing ->cpus_allowedThomas Gleixner2016-05-123-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use the future-safe accessor for struct task_struct's. 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/1462969411-17735-1-git-send-email-bigeasy@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/loadavg: Fix loadavg artifacts on fully idle and on fully loaded systemsVik Heyndrickx2016-05-121-4/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Systems show a minimal load average of 0.00, 0.01, 0.05 even when they have no load at all. Uptime and /proc/loadavg on all systems with kernels released during the last five years up until kernel version 4.6-rc5, show a 5- and 15-minute minimum loadavg of 0.01 and 0.05 respectively. This should be 0.00 on idle systems, but the way the kernel calculates this value prevents it from getting lower than the mentioned values. Likewise but not as obviously noticeable, a fully loaded system with no processes waiting, shows a maximum 1/5/15 loadavg of 1.00, 0.99, 0.95 (multiplied by number of cores). Once the (old) load becomes 93 or higher, it mathematically can never get lower than 93, even when the active (load) remains 0 forever. This results in the strange 0.00, 0.01, 0.05 uptime values on idle systems. Note: 93/2048 = 0.0454..., which rounds up to 0.05. It is not correct to add a 0.5 rounding (=1024/2048) here, since the result from this function is fed back into the next iteration again, so the result of that +0.5 rounding value then gets multiplied by (2048-2037), and then rounded again, so there is a virtual "ghost" load created, next to the old and active load terms. By changing the way the internally kept value is rounded, that internal value equivalent now can reach 0.00 on idle, and 1.00 on full load. Upon increasing load, the internally kept load value is rounded up, when the load is decreasing, the load value is rounded down. The modified code was tested on nohz=off and nohz kernels. It was tested on vanilla kernel 4.6-rc5 and on centos 7.1 kernel 3.10.0-327. It was tested on single, dual, and octal cores system. It was tested on virtual hosts and bare hardware. No unwanted effects have been observed, and the problems that the patch intended to fix were indeed gone. Tested-by: Damien Wyart <damien.wyart@free.fr> Signed-off-by: Vik Heyndrickx <vik.heyndrickx@veribox.net> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <stable@vger.kernel.org> Cc: Doug Smythies <dsmythies@telus.net> 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: 0f004f5a696a ("sched: Cure more NO_HZ load average woes") Link: http://lkml.kernel.org/r/e8d32bff-d544-7748-72b5-3c86cc71f09f@veribox.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/fair: Correct unit of load_above_capacityMorten Rasmussen2016-05-121-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In calculate_imbalance() load_above_capacity currently has the unit [capacity] while it is used as being [load/capacity]. Not only is it wrong it also makes it unlikely that load_above_capacity is ever used as the subsequent code picks the smaller of load_above_capacity and the avg_load This patch ensures that load_above_capacity has the right unit [load/capacity]. Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> [ Changed changelog to note it was in capacity unit; +rebase. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Dietmar Eggemann <dietmar.eggemann@arm.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> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/1461958364-675-4-git-send-email-dietmar.eggemann@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/fair: Clean up scale confusionPeter Zijlstra2016-05-121-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Wanpeng noted that the scale_load_down() in calculate_imbalance() was weird. I agree, it should be SCHED_CAPACITY_SCALE, since we're going to compare against busiest->group_capacity, which is in [capacity] units. Reported-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yuyang Du <yuyang.du@intel.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/nohz: Fix affine unpinned timers messWanpeng Li2016-05-121-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following commit: 9642d18eee2c ("nohz: Affine unpinned timers to housekeepers")' intended to affine unpinned timers to housekeepers: unpinned timers(full dynaticks, idle) => nearest busy housekeepers(otherwise, fallback to any housekeepers) unpinned timers(full dynaticks, busy) => nearest busy housekeepers(otherwise, fallback to any housekeepers) unpinned timers(houserkeepers, idle) => nearest busy housekeepers(otherwise, fallback to itself) However, the !idle_cpu(i) && is_housekeeping_cpu(cpu) check modified the intention to: unpinned timers(full dynaticks, idle) => any housekeepers(no mattter cpu topology) unpinned timers(full dynaticks, busy) => any housekeepers(no mattter cpu topology) unpinned timers(housekeepers, idle) => any busy cpus(otherwise, fallback to any housekeepers) This patch fixes it by checking if there are busy housekeepers nearby, otherwise falls to any housekeepers/itself. After the patch: unpinned timers(full dynaticks, idle) => nearest busy housekeepers(otherwise, fallback to any housekeepers) unpinned timers(full dynaticks, busy) => nearest busy housekeepers(otherwise, fallback to any housekeepers) unpinned timers(housekeepers, idle) => nearest busy housekeepers(otherwise, fallback to itself) Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> [ Fixed the changelog. ] Cc: Frederic Weisbecker <fweisbec@gmail.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> Cc: linux-kernel@vger.kernel.org Fixes: 'commit 9642d18eee2c ("nohz: Affine unpinned timers to housekeepers")' Link: http://lkml.kernel.org/r/1462344334-8303-1-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/fair: Fix fairness issue on migrationPeter Zijlstra2016-05-121-6/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pavan reported that in the presence of very light tasks (or cgroups) the placement of migrated tasks can cause severe fairness issues. The problem is that enqueue_entity() places the task before it updates time, thereby it can place the task far in the past (remember that light tasks will shoot virtual time forward at a high speed, so in relation to the pre-existing light task, we can land far in the past). This is done because update_curr() needs the current task, and we might be placing the current task. The obvious solution is to differentiate between the current and any other task; placing the current before we update time, and placing any other task after, such that !curr tasks end up at the current moment in time, and not in the past. This commit re-introduces the previously reverted commit: 3a47d5124a95 ("sched/fair: Fix fairness issue on migration") ... which is now safe to do, after we've also fixed another underlying bug first, in: sched/fair: Prepare to fix fairness problems on migration and cleaned up other details in the migration code: sched/core: Kill sched_class::task_waking Reported-by: Pavan Kondeti <pkondeti@codeaurora.org> 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> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/core: Kill sched_class::task_waking to clean up the migration logicPeter Zijlstra2016-05-123-42/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With sched_class::task_waking being called only when we do set_task_cpu(), we can make sched_class::migrate_task_rq() do the work and eliminate sched_class::task_waking entirely. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Hunter <ahh@google.com> Cc: Ben Segall <bsegall@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Mike Galbraith <efault@gmx.de> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Pavan Kondeti <pkondeti@codeaurora.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: byungchul.park@lge.com Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/fair: Prepare to fix fairness problems on migrationPeter Zijlstra2016-05-122-8/+58
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Mike reported that our recent attempt to fix migration problems: 3a47d5124a95 ("sched/fair: Fix fairness issue on migration") broke interactivity and the signal starve test. We reverted that commit and now let's try it again more carefully, with some other underlying problems fixed first. One problem is that I assumed ENQUEUE_WAKING was only set when we do a cross-cpu wakeup (migration), which isn't true. This means we now destroy the vruntime history of tasks and wakeup-preemption suffers. Cure this by making my assumption true, only call sched_class::task_waking() when we do a cross-cpu wakeup. This avoids the indirect call in the case we do a local wakeup. Reported-by: Mike Galbraith <mgalbraith@suse.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Hunter <ahh@google.com> Cc: Ben Segall <bsegall@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Mike Galbraith <efault@gmx.de> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Pavan Kondeti <pkondeti@codeaurora.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: byungchul.park@lge.com Cc: linux-kernel@vger.kernel.org Fixes: 3a47d5124a95 ("sched/fair: Fix fairness issue on migration") Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/fair: Move record_wakee()Peter Zijlstra2016-05-121-28/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since I want to make ->task_woken() conditional on the task getting migrated, we cannot use it to call record_wakee(). Move it to select_task_rq_fair(), which gets called in almost all the same conditions. The only exception is if the woken task (@p) is CPU-bound (as per the nr_cpus_allowed test in select_task_rq()). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Hunter <ahh@google.com> Cc: Ben Segall <bsegall@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Mike Galbraith <efault@gmx.de> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Pavan Kondeti <pkondeti@codeaurora.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: byungchul.park@lge.com Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | Merge branch 'smp/hotplug' into sched/core, to resolve conflictsIngo Molnar2016-05-123-238/+180
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: kernel/sched/core.c Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched: Make hrtick_notifier an explicit callThomas Gleixner2016-05-061-33/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | No need for an extra notifier. We don't need to handle all these states. It's sufficient to kill the timer when the cpu dies. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160310120025.770528462@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | sched/fair: Make ilb_notifier an explicit callThomas Gleixner2016-05-063-14/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | No need for an extra notifier. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160310120025.693720241@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | sched/hotplug: Move migration CPU_DYING to sched_cpu_dying()Thomas Gleixner2016-05-061-50/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove the hotplug notifier and make it an explicit state. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160310120025.502222097@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | sched/migration: Move CPU_ONLINE into scheduler stateThomas Gleixner2016-05-061-11/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The alleged requirement that the migration notifier has a lower priority than perf is completely undocumented and there is no indication at all that this is true. perf does not even handle the CPU_ONLINE notification and perf really has nothing to do with migration. Move the CPU_ONLINE code into the sched_activate_cpu() state callback. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160310120025.421743581@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | sched/migration: Move calc_load_migrate() into CPU_DYINGThomas Gleixner2016-05-061-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It really does not matter when we fold the load for the outgoing cpu. It's almost dead anyway, so there is no harm if we fail to fold the few microseconds which are required for going fully away. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160310120025.328739226@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | sched/migration: Move prepare transition to SCHED_STARTING stateThomas Gleixner2016-05-061-9/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We can piggy pack that on the SCHED_STARTING state. It's not required before the cpu actually comes online. Name the function proper as it has nothing to do with migration. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160310120025.248226511@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | sched/hotplug: Move sync_rcu to be with set_cpu_active(false)Peter Zijlstra2016-05-061-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The sync_rcu stuff is specificically for clearing bits in the active mask, such that everybody will observe the bit cleared and will not consider the cleared CPU for load-balancing etc. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160310120025.169219710@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | sched/hotplug: Convert cpu_[in]active notifiers to state machineThomas Gleixner2016-05-061-46/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that we reduced everything into single notifiers, it's simple to move them into the hotplug state machine space. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: rt@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | sched: Move sched_domains_numa_masks_clear() to DOWN_PREPAREThomas Gleixner2016-05-061-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is the last operation on the cpu before vanishing. No point in calling that on CPU_DEAD. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: rt@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | sched: Consolidate the notifier mazeThomas Gleixner2016-05-061-105/+69
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We can maintain the ordering of the scheduler cpu hotplug functionality nicely in one notifer. Get rid of the maze. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: rt@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | sched: Allow hotplug notifiers to be setup earlyThomas Gleixner2016-05-061-23/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Prevent the SMP scheduler related notifiers to be executed before the smp scheduler is initialized and install them early. This is a preparatory change for further consolidation of the hotplug notifier maze. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: rt@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | sched: Make set_cpu_rq_start_time() a built in hotplug stateThomas Gleixner2016-05-061-7/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Start distangling the maze of hotplug notifiers in the scheduler. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: rt@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | sched: Allow per-cpu kernel threads to run on online && !activePeter Zijlstra (Intel)2016-05-061-7/+42
| | |/ / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In order to enable symmetric hotplug, we must mirror the online && !active state of cpu-down on the cpu-up side. However, to retain sanity, limit this state to per-cpu kthreads. Aside from the change to set_cpus_allowed_ptr(), which allow moving the per-cpu kthreads on, the other critical piece is the cpu selection for pinned tasks in select_task_rq(). This avoids dropping into select_fallback_rq(). select_fallback_rq() cannot be allowed to select !active cpus because its used to migrate user tasks away. And we do not want to move user tasks onto cpus that are in transition. Requested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Thomas Gleixner <tglx@linutronix.de> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Jan H. Schönherr <jschoenh@amazon.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160301152303.GV6356@twins.programming.kicks-ass.net Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | | Merge branch 'sched/urgent' into sched/core to pick up fixesIngo Molnar2016-05-123-15/+16
|\ \ \ \ | | | | | | | | | | | | | | | Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | Revert "sched/fair: Fix fairness issue on migration"Ingo Molnar2016-05-111-14/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Mike reported that this recent commit: 3a47d5124a95 ("sched/fair: Fix fairness issue on migration") ... broke interactivity and the signal starvation test. We have a proper fix series in the works but ran out of time for v4.6, so revert the commit. Reported-by: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | sched/rt, sched/dl: Don't push if task's scheduling class was changedXunlei Pang2016-05-102-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | | sched/fair: Fix !CONFIG_SMP kernel cpufreq governor breakageRafael J. Wysocki2016-05-071-1/+8
| | |/ / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following commit: 34e2c555f3e1 ("cpufreq: Add mechanism for registering utilization update callbacks") overlooked the fact that update_load_avg(), where CFS invokes cpufreq utilization update callbacks, becomes an empty stub on UP kernels. In consequence, if !CONFIG_SMP, cpufreq governors are never invoked from CFS and they do not have a chance to evaluate CPU performace levels and update them often enough. Needless to say, things don't work as expected then. Fix the problem by making the !CONFIG_SMP stub of update_load_avg() invoke cpufreq update callbacks too. Reported-by: Steve Muckle <steve.muckle@linaro.org> Tested-by: Steve Muckle <steve.muckle@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Steve Muckle <steve.muckle@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Linux PM list <linux-pm@vger.kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Fixes: 34e2c555f3e1 (cpufreq: Add mechanism for registering utilization update callbacks) Link: http://lkml.kernel.org/r/6282396.VVEdgVYxO3@vostro.rjw.lan Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/core: Fix comment typo in wake_q_add()Davidlohr Bueso2016-05-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... the comment clearly refers to wake_up_q(), and not wake_up_list(). Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dave@stgolabs.net Link: http://lkml.kernel.org/r/1462766290-28664-1-git-send-email-dave@stgolabs.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/core: Remove unused variableMuhammad Falak R Wani2016-05-091-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove unused variable 'ret', and directly return 0. Signed-off-by: Muhammad Falak R Wani <falakreyaz@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/1462441879-10092-1-git-send-email-falakreyaz@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/fair: Fix comment in calculate_imbalance()Dietmar Eggemann2016-05-051-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The comment in calculate_imbalance() was introduced in commit: 2dd73a4f09be ("[PATCH] sched: implement smpnice") which described the logic as it was then, but a later commit: b18855500fc4 ("sched/balancing: Fix 'local->avg_load > sds->avg_load' case in calculate_imbalance()") .. complicated this logic some more so that the comment does not match anymore. Update the comment to match the code. Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1461958364-675-3-git-send-email-dietmar.eggemann@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/fair: Remove stale power aware scheduling commentsDietmar Eggemann2016-05-051-10/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 8e7fbcbc22c1 ("sched: Remove stale power aware scheduling remnants and dysfunctional knobs") deleted the power aware scheduling support. This patch gets rid of the remaining power aware scheduling related comments in the code as well. Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1461958364-675-2-git-send-email-dietmar.eggemann@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/fair: Update rq clock before updating nohz CPU loadMatt Fleming2016-05-051-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If we're accessing rq_clock() (e.g. in sched_avg_update()) we should update the rq clock before calling cpu_load_update(), otherwise any time calculations will be stale. All other paths currently call update_rq_clock(). Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> 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: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1462304814-11715-1-git-send-email-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/debug: Print out idle balance values even on !CONFIG_SCHEDSTATS kernelsWanpeng Li2016-05-051-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The max_idle_balance_cost and avg_idle values which are tracked and ar used to capture short idle incidents, are not associated with schedstats, however the information of these two values isn't printed out on !CONFIG_SCHEDSTATS kernels. Fix this by moving the value printout out of the CONFIG_SCHEDSTATS section. Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.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/1462250305-4523-1-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/fair: Optimize sum computation with a lookup tableYuyang Du2016-05-051-8/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __compute_runnable_contrib() uses a loop to compute sum, whereas a table lookup can do it faster in a constant amount of time. The program to generate the constants is located at: Documentation/scheduler/sched-avg.txt Signed-off-by: Yuyang Du <yuyang.du@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Morten Rasmussen <morten.rasmussen@arm.com> Acked-by: Vincent Guittot <vincent.guittot@linaro.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> Cc: bsegall@google.com Cc: dietmar.eggemann@arm.com Cc: juri.lelli@arm.com Cc: pjt@google.com Link: http://lkml.kernel.org/r/1462226078-31904-2-git-send-email-yuyang.du@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/fair: Rename SCHED_LOAD_SHIFT to NICE_0_LOAD_SHIFT and remove ↵Yuyang Du2016-05-052-13/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | SCHED_LOAD_SCALE After cleaning up the sched metrics, there are two definitions that are ambiguous and confusing: SCHED_LOAD_SHIFT and SCHED_LOAD_SHIFT. Resolve this: - Rename SCHED_LOAD_SHIFT to NICE_0_LOAD_SHIFT, which better reflects what it is. - Replace SCHED_LOAD_SCALE use with SCHED_CAPACITY_SCALE and remove SCHED_LOAD_SCALE. Suggested-by: Ben Segall <bsegall@google.com> Signed-off-by: Yuyang Du <yuyang.du@intel.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> Cc: dietmar.eggemann@arm.com Cc: lizefan@huawei.com Cc: morten.rasmussen@arm.com Cc: pjt@google.com Cc: umgwanakikbuti@gmail.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1459829551-21625-3-git-send-email-yuyang.du@intel.com [ Rewrote the changelog and fixed the build on 32-bit kernels. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/fair: Generalize the load/util averages resolution definitionYuyang Du2016-05-052-9/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Integer metric needs fixed point arithmetic. In sched/fair, a few metrics, e.g., weight, load, load_avg, util_avg, freq, and capacity, may have different fixed point ranges, which makes their update and usage error-prone. In order to avoid the errors relating to the fixed point range, we definie a basic fixed point range, and then formalize all metrics to base on the basic range. The basic range is 1024 or (1 << 10). Further, one can recursively apply the basic range to have larger range. Pointed out by Ben Segall, weight (visible to user, e.g., NICE-0 has 1024) and load (e.g., NICE_0_LOAD) have independent ranges, but they must be well calibrated. Signed-off-by: Yuyang Du <yuyang.du@intel.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> Cc: bsegall@google.com Cc: dietmar.eggemann@arm.com Cc: lizefan@huawei.com Cc: morten.rasmussen@arm.com Cc: pjt@google.com Cc: umgwanakikbuti@gmail.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1459829551-21625-2-git-send-email-yuyang.du@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/core: Enable increased load resolution on 64-bit kernelsPeter Zijlstra2016-05-051-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Mike ran into the low load resolution limitation on his big machine. So reenable these bits; nobody could ever reproduce/analyze the reported power usage claim and Google has been running with this for years as well. Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com> Tested-by: Mike Galbraith <umgwanakikbuti@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> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | locking/lockdep, sched/core: Implement a better lock pinning schemePeter Zijlstra2016-05-057-53/+61
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | | sched/core: Introduce 'struct rq_flags'Peter Zijlstra2016-05-053-56/+62
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In order to be able to pass around more than just the IRQ flags in the future, add a rq_flags structure. No difference in code generation for the x86_64-defconfig build I tested. 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> Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | sched/core: Move task_rq_lock() out of linePeter Zijlstra2016-05-052-63/+69
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Its a rather large function, inline doesn't seems to make much sense: $ size defconfig-build/kernel/sched/core.o{.orig,} text data bss dec hex filename 56533 21037 2320 79890 13812 defconfig-build/kernel/sched/core.o.orig 55733 21037 2320 79090 134f2 defconfig-build/kernel/sched/core.o The 'perf bench sched messaging' micro-benchmark shows a visible improvement of 4-5%: $ for i in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor ; do echo performance > $i ; done $ perf stat --null --repeat 25 -- perf bench sched messaging -g 40 -l 5000 pre: 4.582798193 seconds time elapsed ( +- 1.41% ) 4.733374877 seconds time elapsed ( +- 2.10% ) 4.560955136 seconds time elapsed ( +- 1.43% ) 4.631062303 seconds time elapsed ( +- 1.40% ) post: 4.364765213 seconds time elapsed ( +- 0.91% ) 4.454442734 seconds time elapsed ( +- 1.18% ) 4.448893817 seconds time elapsed ( +- 1.41% ) 4.424346872 seconds time elapsed ( +- 0.97% ) 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> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | Merge branch 'sched/urgent' into sched/core, to pick up fixes before ↵Ingo Molnar2016-05-051-13/+16
|\ \ \ \ | |/ / / | | | | | | | | | | | | | | | | applying new changes Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | nohz/full, sched/rt: Fix missed tick-reenabling bug in sched_can_stop_tick()Peter Zijlstra2016-04-281-13/+16
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Chris Metcalf reported a that sched_can_stop_tick() sometimes fails to re-enable the tick. His observed problem is that rq->cfs.nr_running can be 1 even though there are multiple runnable CFS tasks. This happens in the cgroup case, in which case cfs.nr_running is the number of runnable entities for that level. If there is a single runnable cgroup (which can have an arbitrary number of runnable child entries itself) rq->cfs.nr_running will be 1. However, looking at that function I think there's more problems with it. It seems to assume that if there's FIFO tasks, those will run. This is incorrect. The FIFO task can have a lower prio than an RR task, in which case the RR task will run. So the whole fifo_nr_running test seems misplaced, it should go after the rr_nr_running tests. That is, only if !rr_nr_running, can we use fifo_nr_running like this. Reported-by: Chris Metcalf <cmetcalf@mellanox.com> Tested-by: Chris Metcalf <cmetcalf@mellanox.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Wanpeng Li <kernellwp@gmail.com> Fixes: 76d92ac305f2 ("sched: Migrate sched to use new tick dependency mask model") Link: http://lkml.kernel.org/r/20160421160315.GK24771@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | sched/core: Add switch_mm_irqs_off() and use it in the schedulerAndy Lutomirski2016-04-281-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | By default, this is the same thing as switch_mm(). x86 will override it as an optimization. Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: Borislav Petkov <bp@alien8.de> 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/df401df47bdd6be3e389c6f1e3f5310d70e81b2c.1461688545.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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