aboutsummaryrefslogtreecommitdiffstats
path: root/kernel/time/tick-sched.c
Commit message (Collapse)AuthorAgeFilesLines
* timers/nohz: Last resort update jiffies on nohz_full IRQ entryFrederic Weisbecker2021-12-021-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When at least one CPU runs in nohz_full mode, a dedicated timekeeper CPU is guaranteed to stay online and to never stop its tick. Meanwhile on some rare case, the dedicated timekeeper may be running with interrupts disabled for a while, such as in stop_machine. If jiffies stop being updated, a nohz_full CPU may end up endlessly programming the next tick in the past, taking the last jiffies update monotonic timestamp as a stale base, resulting in an tick storm. Here is a scenario where it matters: 0) CPU 0 is the timekeeper and CPU 1 a nohz_full CPU. 1) A stop machine callback is queued to execute somewhere. 2) CPU 0 reaches MULTI_STOP_DISABLE_IRQ while CPU 1 is still in MULTI_STOP_PREPARE. Hence CPU 0 can't do its timekeeping duty. CPU 1 can still take IRQs. 3) CPU 1 receives an IRQ which queues a timer callback one jiffy forward. 4) On IRQ exit, CPU 1 schedules the tick one jiffy forward, taking last_jiffies_update as a base. But last_jiffies_update hasn't been updated for 2 jiffies since the timekeeper has interrupts disabled. 5) clockevents_program_event(), which relies on ktime_get(), observes that the expiration is in the past and therefore programs the min delta event on the clock. 6) The tick fires immediately, goto 3) 7) Tick storm, the nohz_full CPU is drown and takes ages to reach MULTI_STOP_DISABLE_IRQ, which is the only way out of this situation. Solve this with unconditionally updating jiffies if the value is stale on nohz_full IRQ entry. IRQs and other disturbances are expected to be rare enough on nohz_full for the unconditional call to ktime_get() to actually matter. Reported-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Paul E. McKenney <paulmck@kernel.org> Link: https://lore.kernel.org/r/20211026141055.57358-2-frederic@kernel.org
* Merge tag 'timers-nohz-2021-06-28' of ↵Linus Torvalds2021-06-281-41/+88
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timers/nohz updates from Ingo Molnar: - Micro-optimize tick_nohz_full_cpu() - Optimize idle exit tick restarts to be less eager - Optimize tick_nohz_dep_set_task() to only wake up a single CPU. This reduces IPIs and interruptions on nohz_full CPUs. - Optimize tick_nohz_dep_set_signal() in a similar fashion. - Skip IPIs in tick_nohz_kick_task() when trying to kick a non-running task. - Micro-optimize tick_nohz_task_switch() IRQ flags handling to reduce context switching costs. - Misc cleanups and fixes * tag 'timers-nohz-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: MAINTAINERS: Add myself as context tracking maintainer tick/nohz: Call tick_nohz_task_switch() with interrupts disabled tick/nohz: Kick only _queued_ task whose tick dependency is updated tick/nohz: Change signal tick dependency to wake up CPUs of member tasks tick/nohz: Only wake up a single target cpu when kicking a task tick/nohz: Update nohz_full Kconfig help tick/nohz: Update idle_exittime on actual idle exit tick/nohz: Remove superflous check for CONFIG_VIRT_CPU_ACCOUNTING_NATIVE tick/nohz: Conditionally restart tick on idle exit tick/nohz: Evaluate the CPU expression after the static key
| * tick/nohz: Call tick_nohz_task_switch() with interrupts disabledPeter Zijlstra2021-05-131-6/+1
| | | | | | | | | | | | | | | | | | | | | | Call tick_nohz_task_switch() slightly earlier after the context switch to benefit from disabled IRQs. This way the function doesn't need to disable them once more. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20210512232924.150322-10-frederic@kernel.org
| * tick/nohz: Kick only _queued_ task whose tick dependency is updatedMarcelo Tosatti2021-05-131-2/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the tick dependency of a task is updated, we want it to aknowledge the new state and restart the tick if needed. If the task is not running, we don't need to kick it because it will observe the new dependency upon scheduling in. But if the task is running, we may need to send an IPI to it so that it gets notified. Unfortunately we don't have the means to check if a task is running in a race free way. Checking p->on_cpu in a synchronized way against p->tick_dep_mask would imply adding a full barrier between prepare_task_switch() and tick_nohz_task_switch(), which we want to avoid in this fast-path. Therefore we blindly fire an IPI to the task's CPU. Meanwhile we can check if the task is queued on the CPU rq because p->on_rq is always set to TASK_ON_RQ_QUEUED _before_ schedule() and its full barrier that precedes tick_nohz_task_switch(). And if the task is queued on a nohz_full CPU, it also has fair chances to be running as the isolation constraints prescribe running single tasks on full dynticks CPUs. So use this as a trick to check if we can spare an IPI toward a non-running task. NOTE: For the ordering to be correct, it is assumed that we never deactivate a task while it is running, the only exception being the task deactivating itself while scheduling out. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20210512232924.150322-9-frederic@kernel.org
| * tick/nohz: Change signal tick dependency to wake up CPUs of member tasksMarcelo Tosatti2021-05-131-2/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | Rather than waking up all nohz_full CPUs on the system, only wake up the target CPUs of member threads of the signal. Reduces interruptions to nohz_full CPUs. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20210512232924.150322-8-frederic@kernel.org
| * tick/nohz: Only wake up a single target cpu when kicking a taskFrederic Weisbecker2021-05-131-13/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When adding a tick dependency to a task, its necessary to wake up the CPU where the task resides to reevaluate tick dependencies on that CPU. However the current code wakes up all nohz_full CPUs, which is unnecessary. Switch to waking up a single CPU, by using ordering of writes to task->cpu and task->tick_dep_mask. [ mingo: Minor readability edit. ] Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20210512232924.150322-7-frederic@kernel.org
| * tick/nohz: Update idle_exittime on actual idle exitYunfeng Ye2021-05-131-6/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The idle_exittime field of tick_sched is used to record the time when the idle state was left. but currently the idle_exittime is updated in the function tick_nohz_restart_sched_tick(), which is not always in idle state when nohz_full is configured: tick_irq_exit tick_nohz_irq_exit tick_nohz_full_update_tick tick_nohz_restart_sched_tick ts->idle_exittime = now; It's thus overwritten by mistake on nohz_full tick restart. Move the update to the appropriate idle exit path instead. Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20210512232924.150322-5-frederic@kernel.org
| * tick/nohz: Remove superflous check for CONFIG_VIRT_CPU_ACCOUNTING_NATIVEFrederic Weisbecker2021-05-131-2/+0
| | | | | | | | | | | | | | | | | | | | | | The vtime_accounting_enabled_this_cpu() early check already makes what follows as dead code in the case of CONFIG_VIRT_CPU_ACCOUNTING_NATIVE. No need to keep the ifdeferry around. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20210512232924.150322-4-frederic@kernel.org
| * tick/nohz: Conditionally restart tick on idle exitYunfeng Ye2021-05-131-15/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In nohz_full mode, switching from idle to a task will unconditionally issue a tick restart. If the task is alone in the runqueue or is the highest priority, the tick will fire once then eventually stop. But that alone is still undesired noise. Therefore, only restart the tick on idle exit when it's strictly necessary. Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20210512232924.150322-3-frederic@kernel.org
* | tick/nohz: Only check for RCU deferred wakeup on user/guest entry when neededFrederic Weisbecker2021-05-311-0/+1
|/ | | | | | | | | | | | | | | | | | | Checking for and processing RCU-nocb deferred wakeup upon user/guest entry is only relevant when nohz_full runs on the local CPU, otherwise the periodic tick should take care of it. Make sure we don't needlessly pollute these fast-paths as a -3% performance regression on a will-it-scale.per_process_ops has been reported so far. Fixes: 47b8ff194c1f (entry: Explicitly flush pending rcuog wakeup before last rescheduling point) Fixes: 4ae7dc97f726 (entry/kvm: Explicitly flush pending rcuog wakeup before last rescheduling point) Reported-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20210527113441.465489-1-frederic@kernel.org
* Merge tag 'pm-5.13-rc1' of ↵Linus Torvalds2021-04-261-1/+5
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management updates from Rafael Wysocki: "These add some new hardware support (for example, IceLake-D idle states in intel_idle), fix some issues (for example, the handling of negative "sleep length" values in cpuidle governors), add new functionality to the existing drivers (for example, scale-invariance support in the ACPI CPPC cpufreq driver) and clean up code all over. Specifics: - Add idle states table for IceLake-D to the intel_idle driver and update IceLake-X C6 data in it (Artem Bityutskiy). - Fix the C7 idle state on Tegra114 in the tegra cpuidle driver and drop the unused do_idle() firmware call from it (Dmitry Osipenko). - Fix cpuidle-qcom-spm Kconfig entry (He Ying). - Fix handling of possible negative tick_nohz_get_next_hrtimer() return values of in cpuidle governors (Rafael Wysocki). - Add support for frequency-invariance to the ACPI CPPC cpufreq driver and update the frequency-invariance engine (FIE) to use it as needed (Viresh Kumar). - Simplify the default delay_us setting in the ACPI CPPC cpufreq driver (Tom Saeger). - Clean up frequency-related computations in the intel_pstate cpufreq driver (Rafael Wysocki). - Fix TBG parent setting for load levels in the armada-37xx cpufreq driver and drop the CPU PM clock .set_parent method for armada-37xx (Marek Behún). - Fix multiple issues in the armada-37xx cpufreq driver (Pali Rohár). - Fix handling of dev_pm_opp_of_cpumask_add_table() return values in cpufreq-dt to take the -EPROBE_DEFER one into acconut as appropriate (Quanyang Wang). - Fix format string in ia64-acpi-cpufreq (Sergei Trofimovich). - Drop the unused for_each_policy() macro from cpufreq (Shaokun Zhang). - Simplify computations in the schedutil cpufreq governor to avoid unnecessary overhead (Yue Hu). - Fix typos in the s5pv210 cpufreq driver (Bhaskar Chowdhury). - Fix cpufreq documentation links in Kconfig (Alexander Monakov). - Fix PCI device power state handling in pci_enable_device_flags() to avoid issuse in some cases when the device depends on an ACPI power resource (Rafael Wysocki). - Add missing documentation of pm_runtime_resume_and_get() (Alan Stern). - Add missing static inline stub for pm_runtime_has_no_callbacks() to pm_runtime.h and drop the unused try_to_freeze_nowarn() definition (YueHaibing). - Drop duplicate struct device declaration from pm.h and fix a structure type declaration in intel_rapl.h (Wan Jiabing). - Use dev_set_name() instead of an open-coded equivalent of it in the wakeup sources code and drop a redundant local variable initialization from it (Andy Shevchenko, Colin Ian King). - Use crc32 instead of md5 for e820 memory map integrity check during resume from hibernation on x86 (Chris von Recklinghausen). - Fix typos in comments in the system-wide and hibernation support code (Lu Jialin). - Modify the generic power domains (genpd) code to avoid resuming devices in the "prepare" phase of system-wide suspend and hibernation (Ulf Hansson). - Add Hygon Fam18h RAPL support to the intel_rapl power capping driver (Pu Wen). - Add MAINTAINERS entry for the dynamic thermal power management (DTPM) code (Daniel Lezcano). - Add devm variants of operating performance points (OPP) API functions and switch over some users of the OPP framework to the new resource-managed API (Yangtao Li and Dmitry Osipenko). - Update devfreq core: * Register devfreq devices as cooling devices on demand (Daniel Lezcano). * Add missing unlock opeation in devfreq_add_device() (Lukasz Luba). * Use the next frequency as resume_freq instead of the previous frequency when using the opp-suspend property (Dong Aisheng). * Check get_dev_status in devfreq_update_stats() (Dong Aisheng). * Fix set_freq path for the userspace governor in Kconfig (Dong Aisheng). * Remove invalid description of get_target_freq() (Dong Aisheng). - Update devfreq drivers: * imx8m-ddrc: Remove imx8m_ddrc_get_dev_status() and unneeded of_match_ptr() (Dong Aisheng, Fabio Estevam). * rk3399_dmc: dt-bindings: Add rockchip,pmu phandle and drop references to undefined symbols (Enric Balletbo i Serra, Gaël PORTAY). * rk3399_dmc: Use dev_err_probe() to simplify the code (Krzysztof Kozlowski). * imx-bus: Remove unneeded of_match_ptr() (Fabio Estevam). - Fix kernel-doc warnings in three places (Pierre-Louis Bossart). - Fix typo in the pm-graph utility code (Ricardo Ribalda)" * tag 'pm-5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (74 commits) PM: wakeup: remove redundant assignment to variable retval PM: hibernate: x86: Use crc32 instead of md5 for hibernation e820 integrity check cpufreq: Kconfig: fix documentation links PM: wakeup: use dev_set_name() directly PM: runtime: Add documentation for pm_runtime_resume_and_get() cpufreq: intel_pstate: Simplify intel_pstate_update_perf_limits() cpufreq: armada-37xx: Fix module unloading cpufreq: armada-37xx: Remove cur_frequency variable cpufreq: armada-37xx: Fix determining base CPU frequency cpufreq: armada-37xx: Fix driver cleanup when registration failed clk: mvebu: armada-37xx-periph: Fix workaround for switching from L1 to L0 clk: mvebu: armada-37xx-periph: Fix switching CPU freq from 250 Mhz to 1 GHz cpufreq: armada-37xx: Fix the AVS value for load L1 clk: mvebu: armada-37xx-periph: remove .set_parent method for CPU PM clock cpufreq: armada-37xx: Fix setting TBG parent for load levels cpuidle: Fix ARM_QCOM_SPM_CPUIDLE configuration cpuidle: tegra: Remove do_idle firmware call cpuidle: tegra: Fix C7 idling state on Tegra114 PM: sleep: fix typos in comments cpufreq: Remove unused for_each_policy macro ...
| * tick/nohz: Improve tick_nohz_get_next_hrtimer() kerneldocRafael J. Wysocki2021-04-071-1/+5
| | | | | | | | | | | | | | Make the tick_nohz_get_next_hrtimer() kerneldoc comment state clearly that the function may return negative numbers. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | Merge tag 'timers-core-2021-04-26' of ↵Linus Torvalds2021-04-261-1/+1
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner: "The time and timers updates contain: Core changes: - Allow runtime power management when the clocksource is changed. - A correctness fix for clock_adjtime32() so that the return value on success is not overwritten by the result of the copy to user. - Allow late installment of broadcast clockevent devices which was broken because nothing switched them over to oneshot mode. This went unnoticed so far because clockevent devices used to be built in, but now people started to make them modular. - Debugfs related simplifications - Small cleanups and improvements here and there Driver changes: - The usual set of device tree binding updates for a wide range of drivers/devices. - The usual updates and improvements for drivers all over the place but nothing outstanding. - No new clocksource/event drivers. They'll come back next time" * tag 'timers-core-2021-04-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) posix-timers: Preserve return value in clock_adjtime32() tick/broadcast: Allow late registered device to enter oneshot mode tick: Use tick_check_replacement() instead of open coding it time/timecounter: Mark 1st argument of timecounter_cyc2time() as const dt-bindings: timer: nuvoton,npcm7xx: Add wpcm450-timer clocksource/drivers/arm_arch_timer: Add __ro_after_init and __init clocksource/drivers/timer-ti-dm: Handle dra7 timer wrap errata i940 clocksource/drivers/timer-ti-dm: Prepare to handle dra7 timer wrap issue clocksource/drivers/dw_apb_timer_of: Add handling for potential memory leak clocksource/drivers/npcm: Add support for WPCM450 clocksource/drivers/sh_cmt: Don't use CMTOUT_IE with R-Car Gen2/3 clocksource/drivers/pistachio: Fix trivial typo clocksource/drivers/ingenic_ost: Fix return value check in ingenic_ost_probe() clocksource/drivers/timer-ti-dm: Add missing set_state_oneshot_stopped clocksource/drivers/timer-ti-dm: Fix posted mode status check order dt-bindings: timer: renesas,cmt: Document R8A77961 dt-bindings: timer: renesas,cmt: Add r8a779a0 CMT support clocksource/drivers/ingenic-ost: Add support for the JZ4760B clocksource/drivers/ingenic: Add support for the JZ4760 dt-bindings: timer: ingenic: Add compatible strings for JZ4760(B) ...
| * | timekeeping, clocksource: Fix various typos in commentsIngo Molnar2021-03-221-1/+1
| |/ | | | | | | | | | | | | | | | | | | | | Fix ~56 single-word typos in timekeeping & clocksource code comments. Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Stephen Boyd <sboyd@kernel.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: linux-kernel@vger.kernel.org
* / tick/sched: Prevent false positive softirq pending warnings on RTThomas Gleixner2021-03-171-1/+1
|/ | | | | | | | | | | | | | | | | | | | On RT a task which has soft interrupts disabled can block on a lock and schedule out to idle while soft interrupts are pending. This triggers the warning in the NOHZ idle code which complains about going idle with pending soft interrupts. But as the task is blocked soft interrupt processing is temporarily blocked as well which means that such a warning is a false positive. To prevent that check the per CPU state which indicates that a scheduled out task has soft interrupts disabled. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Tested-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210309085727.527563866@linutronix.de
* Merge tag 'timers-urgent-2020-12-27' of ↵Linus Torvalds2020-12-271-7/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fixes from Ingo Molnar: "Update/fix two CPU sanity checks in the hotplug and the boot code, and fix a typo in the Kconfig help text. [ Context: the first two commits are the result of an ongoing annotation+review work of (intentional) tick_do_timer_cpu() data races reported by KCSAN, but the annotations aren't fully cooked yet ]" * tag 'timers-urgent-2020-12-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timekeeping: Fix spelling mistake in Kconfig "fullfill" -> "fulfill" tick/sched: Remove bogus boot "safety" check tick: Remove pointless cpu valid check in hotplug code
| * tick/sched: Remove bogus boot "safety" checkThomas Gleixner2020-12-161-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | can_stop_idle_tick() checks whether the do_timer() duty has been taken over by a CPU on boot. That's silly because the boot CPU always takes over with the initial clockevent device. But even if no CPU would have installed a clockevent and taken over the duty then the question whether the tick on the current CPU can be stopped or not is moot. In that case the current CPU would have no clockevent either, so there would be nothing to keep ticking. Remove it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20201206212002.725238293@linutronix.de
* | Merge tag 'sched-core-2020-12-14' of ↵Linus Torvalds2020-12-141-4/+2
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Thomas Gleixner: - migrate_disable/enable() support which originates from the RT tree and is now a prerequisite for the new preemptible kmap_local() API which aims to replace kmap_atomic(). - A fair amount of topology and NUMA related improvements - Improvements for the frequency invariant calculations - Enhanced robustness for the global CPU priority tracking and decision making - The usual small fixes and enhancements all over the place * tag 'sched-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (61 commits) sched/fair: Trivial correction of the newidle_balance() comment sched/fair: Clear SMT siblings after determining the core is not idle sched: Fix kernel-doc markup x86: Print ratio freq_max/freq_base used in frequency invariance calculations x86, sched: Use midpoint of max_boost and max_P for frequency invariance on AMD EPYC x86, sched: Calculate frequency invariance for AMD systems irq_work: Optimize irq_work_single() smp: Cleanup smp_call_function*() irq_work: Cleanup sched: Limit the amount of NUMA imbalance that can exist at fork time sched/numa: Allow a floating imbalance between NUMA nodes sched: Avoid unnecessary calculation of load imbalance at clone time sched/numa: Rename nr_running and break out the magic number sched: Make migrate_disable/enable() independent of RT sched/topology: Condition EAS enablement on FIE support arm64: Rebuild sched domains on invariance status changes sched/topology,schedutil: Wrap sched domains rebuild sched/uclamp: Allow to reset a task uclamp constraint value sched/core: Fix typos in comments Documentation: scheduler: fix information on arch SD flags, sched_domain and sched_debug ...
| * irq_work: CleanupPeter Zijlstra2020-11-241-4/+2
| | | | | | | | | | | | | | | | Get rid of the __call_single_node union and clean up the API a little to avoid external code relying on the structure layout as much. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
* | tick/sched: Make jiffies update quick check more robustThomas Gleixner2020-12-111-27/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The quick check in tick_do_update_jiffies64() whether jiffies need to be updated is not really correct under all circumstances and on all architectures, especially not on 32bit systems. The quick check does: if (now < READ_ONCE(tick_next_period)) return; and the counterpart in the update is: WRITE_ONCE(tick_next_period, next_update_time); This has two problems: 1) On weakly ordered architectures there is no guarantee that the stores before the WRITE_ONCE() are visible which means that other CPUs can operate on a stale jiffies value. 2) On 32bit the store of tick_next_period which is an u64 is split into two 32bit stores. If the first 32bit store advances tick_next_period far out and the second 32bit store is delayed (virt, NMI ...) then jiffies will become stale until the second 32bit store happens. Address this by seperating the handling for 32bit and 64bit. On 64bit problem #1 is addressed by replacing READ_ONCE() / WRITE_ONCE() with smp_load_acquire() / smp_store_release(). On 32bit problem #2 is addressed by protecting the quick check with the jiffies sequence counter. The load and stores can be plain because the sequence count mechanics provides the required barriers already. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/87czzpc02w.fsf@nanos.tec.linutronix.de
* | tick: Get rid of tick_periodThomas Gleixner2020-11-191-11/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The variable tick_period is initialized to NSEC_PER_TICK / HZ during boot and never updated again. If NSEC_PER_TICK is not an integer multiple of HZ this computation is less accurate than TICK_NSEC which has proper rounding in place. Aside of the inaccuracy there is no reason for having this variable at all. It's just a pointless indirection and all usage sites can just use the TICK_NSEC constant. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201117132006.766643526@linutronix.de
* | tick/sched: Release seqcount before invoking calc_load_global()Yunfeng Ye2020-11-191-1/+11
| | | | | | | | | | | | | | | | | | | | | | calc_load_global() does not need the sequence count protection. [ tglx: Split it up properly and added comments ] Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201117132006.660902274@linutronix.de
* | tick/sched: Optimize tick_do_update_jiffies64() furtherThomas Gleixner2020-11-191-5/+6
| | | | | | | | | | | | | | | | | | Now that it's clear that there is always one tick to account, simplify the calculations some more. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201117132006.565663056@linutronix.de
* | tick/sched: Reduce seqcount held scope in tick_do_update_jiffies64()Yunfeng Ye2020-11-191-25/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If jiffies are up to date already (caller lost the race against another CPU) there is no point to change the sequence count. Doing that just forces other CPUs into the seqcount retry loop in tick_nohz_next_event() for nothing. Just bail out early. [ tglx: Rewrote most of it ] Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201117132006.462195901@linutronix.de
* | tick/sched: Use tick_next_period for lockless quick checkThomas Gleixner2020-11-191-13/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | No point in doing calculations. tick_next_period = last_jiffies_update + tick_period Just check whether now is before tick_next_period to figure out whether jiffies need an update. Add a comment why the intentional data race in the quick check is safe or not so safe in a 32bit corner case and why we don't worry about it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201117132006.337366695@linutronix.de
* | tick: Document protections for tick related dataThomas Gleixner2020-11-191-1/+3
|/ | | | | | | | | The protection rules for tick_next_period and last_jiffies_update are blury at best. Clarify this. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201117132006.197713794@linutronix.de
* tick-sched: Clarify "NOHZ: local_softirq_pending" warningPaul E. McKenney2020-08-241-1/+1
| | | | | | | | | | | | | | | Currently, can_stop_idle_tick() prints "NOHZ: local_softirq_pending HH" (where "HH" is the hexadecimal softirq vector number) when one or more non-RCU softirq handlers are still enabled when checking to stop the scheduler-tick interrupt. This message is not as enlightening as one might hope, so this commit changes it to "NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #HH". Reported-by: Andy Lutomirski <luto@kernel.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
* tick/nohz: Narrow down noise while setting current task's tick dependencyFrederic Weisbecker2020-06-291-7/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Setting a tick dependency on any task, including the case where a task sets that dependency on itself, triggers an IPI to all CPUs. That is of course suboptimal but it had previously not been an issue because it was only used by POSIX CPU timers on nohz_full, which apparently never occurs in latency-sensitive workloads in production. (Or users of such systems are suffering in silence on the one hand or venting their ire on the wrong people on the other.) But RCU now sets a task tick dependency on the current task in order to fix stall issues that can occur during RCU callback processing. Thus, RCU callback processing triggers frequent system-wide IPIs from nohz_full CPUs. This is quite counter-productive, after all, avoiding IPIs is what nohz_full is supposed to be all about. This commit therefore optimizes tasks' self-setting of a task tick dependency by using tick_nohz_full_kick() to avoid the system-wide IPI. Instead, only the execution of the one task is disturbed, which is acceptable given that this disturbance is well down into the noise compared to the degree to which the RCU callback processing itself disturbs execution. Fixes: 6a949b7af82d (rcu: Force on tick when invoking lots of callbacks) Reported-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: stable@kernel.org Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
* lockdep: Annotate irq_workSebastian Andrzej Siewior2020-03-211-0/+1
| | | | | | | | | | | | | | Mark irq_work items with IRQ_WORK_HARD_IRQ which should be invoked in hardirq context even on PREEMPT_RT. IRQ_WORK without this flag will be invoked in softirq context on PREEMPT_RT. Set ->irq_config to 1 for the IRQ_WORK items which are invoked in softirq context so lockdep knows that these can safely acquire a spinlock_t. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200321113242.643576700@linutronix.de
* timekeeping: Split jiffies seqlockThomas Gleixner2020-03-211-7/+12
| | | | | | | | | | | | | | | | | | | | seqlock consists of a sequence counter and a spinlock_t which is used to serialize the writers. spinlock_t is substituted by a "sleeping" spinlock on PREEMPT_RT enabled kernels which breaks the usage in the timekeeping code as the writers are executed in hard interrupt and therefore non-preemptible context even on PREEMPT_RT. The spinlock in seqlock cannot be unconditionally replaced by a raw_spinlock_t as many seqlock users have nesting spinlock sections or other code which is not suitable to run in truly atomic context on RT. Instead of providing a raw_seqlock API for a single use case, open code the seqlock for the jiffies use case and implement it with a raw_spinlock_t and a sequence counter. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200321113242.120587764@linutronix.de
* tick/sched: Annotate lockless access to last_jiffies_updateEric Dumazet2020-01-151-5/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | syzbot (KCSAN) reported a data-race in tick_do_update_jiffies64(): BUG: KCSAN: data-race in tick_do_update_jiffies64 / tick_do_update_jiffies64 write to 0xffffffff8603d008 of 8 bytes by interrupt on cpu 1: tick_do_update_jiffies64+0x100/0x250 kernel/time/tick-sched.c:73 tick_sched_do_timer+0xd4/0xe0 kernel/time/tick-sched.c:138 tick_sched_timer+0x43/0xe0 kernel/time/tick-sched.c:1292 __run_hrtimer kernel/time/hrtimer.c:1514 [inline] __hrtimer_run_queues+0x274/0x5f0 kernel/time/hrtimer.c:1576 hrtimer_interrupt+0x22a/0x480 kernel/time/hrtimer.c:1638 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0xdc/0x280 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 arch_local_irq_restore arch/x86/include/asm/paravirt.h:756 [inline] kcsan_setup_watchpoint+0x1d4/0x460 kernel/kcsan/core.c:436 check_access kernel/kcsan/core.c:466 [inline] __tsan_read1 kernel/kcsan/core.c:593 [inline] __tsan_read1+0xc2/0x100 kernel/kcsan/core.c:593 kallsyms_expand_symbol.constprop.0+0x70/0x160 kernel/kallsyms.c:79 kallsyms_lookup_name+0x7f/0x120 kernel/kallsyms.c:170 insert_report_filterlist kernel/kcsan/debugfs.c:155 [inline] debugfs_write+0x14b/0x2d0 kernel/kcsan/debugfs.c:256 full_proxy_write+0xbd/0x100 fs/debugfs/file.c:225 __vfs_write+0x67/0xc0 fs/read_write.c:494 vfs_write fs/read_write.c:558 [inline] vfs_write+0x18a/0x390 fs/read_write.c:542 ksys_write+0xd5/0x1b0 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write fs/read_write.c:620 [inline] __x64_sys_write+0x4c/0x60 fs/read_write.c:620 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffffffff8603d008 of 8 bytes by task 0 on cpu 0: tick_do_update_jiffies64+0x2b/0x250 kernel/time/tick-sched.c:62 tick_nohz_update_jiffies kernel/time/tick-sched.c:505 [inline] tick_nohz_irq_enter kernel/time/tick-sched.c:1257 [inline] tick_irq_enter+0x139/0x1c0 kernel/time/tick-sched.c:1274 irq_enter+0x4f/0x60 kernel/softirq.c:354 entering_irq arch/x86/include/asm/apic.h:517 [inline] entering_ack_irq arch/x86/include/asm/apic.h:523 [inline] smp_apic_timer_interrupt+0x55/0x280 arch/x86/kernel/apic/apic.c:1133 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:571 default_idle_call+0x1e/0x40 kernel/sched/idle.c:94 cpuidle_idle_call kernel/sched/idle.c:154 [inline] do_idle+0x1af/0x280 kernel/sched/idle.c:263 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:355 rest_init+0xec/0xf6 init/main.c:452 arch_call_rest_init+0x17/0x37 start_kernel+0x838/0x85e init/main.c:786 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:490 x86_64_start_kernel+0x72/0x76 arch/x86/kernel/head64.c:471 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.0-rc7+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Use READ_ONCE() and WRITE_ONCE() to annotate this expected race. Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20191205045619.204946-1-edumazet@google.com
* Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds2019-11-261-0/+11
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU updates from Ingo Molnar: "The main changes in this cycle were: - Dynamic tick (nohz) updates, perhaps most notably changes to force the tick on when needed due to lengthy in-kernel execution on CPUs on which RCU is waiting. - Linux-kernel memory consistency model updates. - Replace rcu_swap_protected() with rcu_prepace_pointer(). - Torture-test updates. - Documentation updates. - Miscellaneous fixes" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (51 commits) security/safesetid: Replace rcu_swap_protected() with rcu_replace_pointer() net/sched: Replace rcu_swap_protected() with rcu_replace_pointer() net/netfilter: Replace rcu_swap_protected() with rcu_replace_pointer() net/core: Replace rcu_swap_protected() with rcu_replace_pointer() bpf/cgroup: Replace rcu_swap_protected() with rcu_replace_pointer() fs/afs: Replace rcu_swap_protected() with rcu_replace_pointer() drivers/scsi: Replace rcu_swap_protected() with rcu_replace_pointer() drm/i915: Replace rcu_swap_protected() with rcu_replace_pointer() x86/kvm/pmu: Replace rcu_swap_protected() with rcu_replace_pointer() rcu: Upgrade rcu_swap_protected() to rcu_replace_pointer() rcu: Suppress levelspread uninitialized messages rcu: Fix uninitialized variable in nocb_gp_wait() rcu: Update descriptions for rcu_future_grace_period tracepoint rcu: Update descriptions for rcu_nocb_wake tracepoint rcu: Remove obsolete descriptions for rcu_barrier tracepoint rcu: Ensure that ->rcu_urgent_qs is set before resched IPI workqueue: Convert for_each_wq to use built-in list check rcu: Several rcu_segcblist functions can be static rcu: Remove unused function hlist_bl_del_init_rcu() Documentation: Rename rcu_node_context_switch() to rcu_note_context_switch() ...
| * time: Export tick start/stop functions for rcutorturePaul E. McKenney2019-10-051-0/+4
| | | | | | | | | | | | | | | | | | | | | | It turns out that rcutorture needs to ensure that the scheduling-clock interrupt is enabled in CONFIG_NO_HZ_FULL kernels before starting on CPU-bound in-kernel processing. This commit therefore exports tick_nohz_dep_set_task(), tick_nohz_dep_clear_task(), and tick_nohz_full_setup() to GPL kernel modules. Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
| * nohz: Add TICK_DEP_BIT_RCUFrederic Weisbecker2019-10-051-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a nohz_full CPU is looping in the kernel, the scheduling-clock tick might nevertheless remain disabled. In !PREEMPT kernels, this can prevent RCU's attempts to enlist the aid of that CPU's executions of cond_resched(), which can in turn result in an arbitrarily delayed grace period and thus an OOM. RCU therefore needs a way to enable a holdout nohz_full CPU's scheduler-clock interrupt. This commit therefore provides a new TICK_DEP_BIT_RCU value which RCU can pass to tick_dep_set_cpu() and friends to force on the scheduler-clock interrupt for a specified CPU or task. In some cases, rcutorture needs to turn on the scheduler-clock tick, so this commit also exports the relevant symbols to GPL-licensed modules. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
* | sched/vtime: Rename vtime_accounting_cpu_enabled() to ↵Frederic Weisbecker2019-10-291-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | vtime_accounting_enabled_this_cpu() Standardize the naming on top of the vtime_accounting_enabled_*() base. Also make it clear we are checking the vtime state of the *current* CPU with this function. We'll need to add an API to check that state on remote CPUs as well, so we must disambiguate the naming. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Pavel Machek <pavel@ucw.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J . Wysocki <rjw@rjwysocki.net> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Wanpeng Li <wanpengli@tencent.com> Cc: Yauheni Kaliuta <yauheni.kaliuta@redhat.com> Link: https://lkml.kernel.org/r/20191016025700.31277-9-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* tick: Mark sched_timer to expire in hard interrupt contextSebastian Andrzej Siewior2019-08-281-1/+1
| | | | | | | | | | | | | | sched_timer must be initialized with the _HARD mode suffix to ensure expiry in hard interrupt context on RT. The previous conversion to HARD expiry mode missed on one instance in tick_nohz_switch_to_nohz(). Fix it up. Fixes: 902a9f9c50905 ("tick: Mark tick related hrtimers to expiry in hard interrupt context") Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190823113845.12125-3-bigeasy@linutronix.de
* tick: Mark tick related hrtimers to expiry in hard interrupt contextSebastian Andrzej Siewior2019-08-011-6/+9
| | | | | | | | | | | | | | | | | | | | | | The tick related hrtimers, which drive the scheduler tick and hrtimer based broadcasting are required to expire in hard interrupt context for obvious reasons. Mark them so PREEMPT_RT kernels wont move them to soft interrupt expiry. Make the horribly formatted RCU_NONIDLE bracket maze readable while at it. No functional change, [ tglx: Split out from larger combo patch. Add changelog ] Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20190726185753.459144407@linutronix.de
* sched/fair: Remove the rq->cpu_load[] update codeDietmar Eggemann2019-06-031-2/+0
| | | | | | | | | | | | | | | | | | | | With LB_BIAS disabled, there is no need to update the rq->cpu_load[idx] any more. Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Rik van Riel <riel@surriel.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Patrick Bellasi <patrick.bellasi@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Perret <quentin.perret@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Valentin Schneider <valentin.schneider@arm.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Link: https://lkml.kernel.org/r/20190527062116.11512-2-dietmar.eggemann@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge tag 'pm-5.2-rc1' of ↵Linus Torvalds2019-05-061-0/+12
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management updates from Rafael Wysocki: "These fix the (Intel-specific) Performance and Energy Bias Hint (EPB) handling and expose it to user space via sysfs, fix and clean up several cpufreq drivers, add support for two new chips to the qoriq cpufreq driver, fix, simplify and clean up the cpufreq core and the schedutil governor, add support for "CPU" domains to the generic power domains (genpd) framework and provide low-level PSCI firmware support for that feature, fix the exynos cpuidle driver and fix a couple of issues in the devfreq subsystem and clean it up. Specifics: - Fix the handling of Performance and Energy Bias Hint (EPB) on Intel processors and expose it to user space via sysfs to avoid having to access it through the generic MSR I/F (Rafael Wysocki). - Improve the handling of global turbo changes made by the platform firmware in the intel_pstate driver (Rafael Wysocki). - Convert some slow-path static_cpu_has() callers to boot_cpu_has() in cpufreq (Borislav Petkov). - Fix the frequency calculation loop in the armada-37xx cpufreq driver (Gregory CLEMENT). - Fix possible object reference leaks in multuple cpufreq drivers (Wen Yang). - Fix kerneldoc comment in the centrino cpufreq driver (dongjian). - Clean up the ACPI and maple cpufreq drivers (Viresh Kumar, Mohan Kumar). - Add support for lx2160a and ls1028a to the qoriq cpufreq driver (Vabhav Sharma, Yuantian Tang). - Fix kobject memory leak in the cpufreq core (Viresh Kumar). - Simplify the IOwait boosting in the schedutil cpufreq governor and rework the TSC cpufreq notifier on x86 (Rafael Wysocki). - Clean up the cpufreq core and statistics code (Yue Hu, Kyle Lin). - Improve the cpufreq documentation, add SPDX license tags to some PM documentation files and unify copyright notices in them (Rafael Wysocki). - Add support for "CPU" domains to the generic power domains (genpd) framework and provide low-level PSCI firmware support for that feature (Ulf Hansson). - Rearrange the PSCI firmware support code and add support for SYSTEM_RESET2 to it (Ulf Hansson, Sudeep Holla). - Improve genpd support for devices in multiple power domains (Ulf Hansson). - Unify target residency for the AFTR and coupled AFTR states in the exynos cpuidle driver (Marek Szyprowski). - Introduce new helper routine in the operating performance points (OPP) framework (Andrew-sh.Cheng). - Add support for passing on-die termination (ODT) and auto power down parameters from the kernel to Trusted Firmware-A (TF-A) to the rk3399_dmc devfreq driver (Enric Balletbo i Serra). - Add tracing to devfreq (Lukasz Luba). - Make the exynos-bus devfreq driver suspend all devices on system shutdown (Marek Szyprowski). - Fix a few minor issues in the devfreq subsystem and clean it up somewhat (Enric Balletbo i Serra, MyungJoo Ham, Rob Herring, Saravana Kannan, Yangtao Li). - Improve system wakeup diagnostics (Stephen Boyd). - Rework filesystem sync messages emitted during system suspend and hibernation (Harry Pan)" * tag 'pm-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (72 commits) cpufreq: Fix kobject memleak cpufreq: armada-37xx: fix frequency calculation for opp cpufreq: centrino: Fix centrino_setpolicy() kerneldoc comment cpufreq: qoriq: add support for lx2160a x86: tsc: Rework time_cpufreq_notifier() PM / Domains: Allow to attach a CPU via genpd_dev_pm_attach_by_id|name() PM / Domains: Search for the CPU device outside the genpd lock PM / Domains: Drop unused in-parameter to some genpd functions PM / Domains: Use the base device for driver_deferred_probe_check_state() cpufreq: qoriq: Add ls1028a chip support PM / Domains: Enable genpd_dev_pm_attach_by_id|name() for single PM domain PM / Domains: Allow OF lookup for multi PM domain case from ->attach_dev() PM / Domains: Don't kfree() the virtual device in the error path cpufreq: Move ->get callback check outside of __cpufreq_get() PM / Domains: remove unnecessary unlikely() cpufreq: Remove needless bios_limit check in show_bios_limit() drivers/cpufreq/acpi-cpufreq.c: This fixes the following checkpatch warning firmware/psci: add support for SYSTEM_RESET2 PM / devfreq: add tracing for scheduling work trace: events: add devfreq trace event file ...
| * cpuidle: Export the next timer expiration for CPUsUlf Hansson2019-04-101-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To be able to predict the sleep duration for a CPU entering idle, it is essential to know the expiration time of the next timer. Both the teo and the menu cpuidle governors already use this information for CPU idle state selection. Moving forward, a similar prediction needs to be made for a group of idle CPUs rather than for a single one and the following changes implement a new genpd governor for that purpose. In order to support that feature, add a new function called tick_nohz_get_next_hrtimer() that will return the next hrtimer expiration time of a given CPU to be invoked after deciding whether or not to stop the scheduler tick on that CPU. Make the cpuidle core call tick_nohz_get_next_hrtimer() right before invoking the ->enter() callback provided by the cpuidle driver for the given state and store its return value in the per-CPU struct cpuidle_device, so as to make it available to code outside of cpuidle. Note that at the point when cpuidle calls tick_nohz_get_next_hrtimer(), the governor's ->select() callback has already returned and indicated whether or not the tick should be stopped, so in fact the value returned by tick_nohz_get_next_hrtimer() always is the next hrtimer expiration time for the given CPU, possibly including the tick (if it hasn't been stopped). Co-developed-by: Lina Iyer <lina.iyer@linaro.org> Co-developed-by: Daniel Lezcano <daniel.lezcano@linaro.org> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> [ rjw: Subject & changelog ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | Merge branch 'timers-core-for-linus' of ↵Linus Torvalds2019-05-061-1/+2
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Ingo Molnar: "This cycle had the following changes: - Timer tracing improvements (Anna-Maria Gleixner) - Continued tasklet reduction work: remove the hrtimer_tasklet (Thomas Gleixner) - Fix CPU hotplug remove race in the tick-broadcast mask handling code (Thomas Gleixner) - Force upper bound for setting CLOCK_REALTIME, to fix ABI inconsistencies with handling values that are close to the maximum supported and the vagueness of when uptime related wraparound might occur. Make the consistent maximum the year 2232 across all relevant ABIs and APIs. (Thomas Gleixner) - various cleanups and smaller fixes" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tick: Fix typos in comments tick/broadcast: Fix warning about undefined tick_broadcast_oneshot_offline() timekeeping: Force upper bound for setting CLOCK_REALTIME timer/trace: Improve timer tracing timer/trace: Replace deprecated vsprintf pointer extension %pf by %ps timer: Move trace point to get proper index tick/sched: Update tick_sched struct documentation tick: Remove outgoing CPU from broadcast masks timekeeping: Consistently use unsigned int for seqcount snapshot softirq: Remove tasklet_hrtimer xfrm: Replace hrtimer tasklet with softirq hrtimer mac80211_hwsim: Replace hrtimer tasklet with softirq hrtimer
| * | timekeeping: Consistently use unsigned int for seqcount snapshotRasmus Villemoes2019-03-231-1/+2
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | The timekeeping code uses a random mix of "unsigned long" and "unsigned int" for the seqcount snapshots (ratio 14:12). Since the seqlock.h API is entirely based on unsigned int, use that throughout. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Stephen Boyd <sboyd@kernel.org> Link: https://lkml.kernel.org/r/20190318195557.20773-1-linux@rasmusvillemoes.dk
* / nohz_full: Allow the boot CPU to be nohz_fullNicholas Piggin2019-05-031-10/+24
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | Allow the boot CPU/CPU0 to be nohz_full. Have the boot CPU take the do_timer duty during boot until a housekeeping CPU can take over. This is supported when CONFIG_PM_SLEEP_SMP is not configured, or when it is configured and the arch allows suspend on non-zero CPUs. nohz_full has been trialed at a large supercomputer site and found to significantly reduce jitter. In order to deploy it in production, they need CPU0 to be nohz_full because their job control system requires the application CPUs to start from 0, and the housekeeping CPUs are placed higher. An equivalent job scheduling that uses CPU0 for housekeeping could be achieved by modifying their system, but it is preferable if nohz_full can support their environment without modification. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linuxppc-dev@lists.ozlabs.org Link: https://lkml.kernel.org/r/20190411033448.20842-6-npiggin@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* hrtimers/tick/clockevents: Remove sloppy license referencesThomas Gleixner2018-11-231-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | "For licencing details see kernel-base/COPYING" and similar license references have no value over the SPDX identifier. Remove them. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: John Stultz <john.stultz@linaro.org> Acked-by: Corey Minyard <cminyard@mvista.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Peter Anvin <hpa@zytor.com> Cc: Russell King <rmk+kernel@armlinux.org.uk> Cc: Richard Cochran <richardcochran@gmail.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: David Riley <davidriley@chromium.org> Cc: Colin Cross <ccross@android.com> Cc: Mark Brown <broonie@kernel.org> Link: https://lkml.kernel.org/r/20181031182252.963632760@linutronix.de
* time: Add SPDX license identifiersThomas Gleixner2018-11-231-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Update the time(r) core files files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Philippe Ombredanne, Kate Stewart and myself. The data has been created with two independent license scanners and manual inspection. The following files do not contain any direct license information and have been omitted from the big initial SPDX changes: timeconst.bc: The .bc files were not touched time.c, timer.c, timekeeping.c: Licence was deduced from EXPORT_SYMBOL_GPL As those files do not contain direct license references they fall under the project license, i.e. GPL V2 only. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: John Stultz <john.stultz@linaro.org> Acked-by: Corey Minyard <cminyard@mvista.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Russell King <rmk+kernel@armlinux.org.uk> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: David Riley <davidriley@chromium.org> Cc: Colin Cross <ccross@android.com> Cc: Mark Brown <broonie@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Link: https://lkml.kernel.org/r/20181031182252.879109557@linutronix.de
* time: Remove useless filenames in top level commentsThomas Gleixner2018-11-231-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | Remove the pointless filenames in the top level comments. They have no value at all and just occupy space. While at it tidy up some of the comments and remove a stale one. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Nicolas Pitre <nico@linaro.org> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: John Stultz <john.stultz@linaro.org> Acked-by: Corey Minyard <cminyard@mvista.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Peter Anvin <hpa@zytor.com> Cc: Russell King <rmk+kernel@armlinux.org.uk> Cc: Richard Cochran <richardcochran@gmail.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: David Riley <davidriley@chromium.org> Cc: Colin Cross <ccross@android.com> Cc: Mark Brown <broonie@kernel.org> Link: https://lkml.kernel.org/r/20181031182252.794898238@linutronix.de
* tick/sched : Remove redundant cpu_online() checkPeng Hao2018-10-101-1/+1
| | | | | | | | | | | can_stop_idle_tick() checks cpu_online() twice. The first check leaves the function when the CPU is not online, so the second check it redundant. Remove it. Signed-off-by: Peng Hao <peng.hao2@zte.com.cn> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: fweisbec@gmail.com Link: https://lkml.kernel.org/r/1539099815-2943-1-git-send-email-penghao122@sina.com.cn
* nohz: Fix local_timer_softirq_pending()Anna-Maria Gleixner2018-07-311-1/+1
| | | | | | | | | | | | | | | | | | | | | | local_timer_softirq_pending() checks whether the timer softirq is pending with: local_softirq_pending() & TIMER_SOFTIRQ. This is wrong because TIMER_SOFTIRQ is the softirq number and not a bitmask. So the test checks for the wrong bit. Use BIT(TIMER_SOFTIRQ) instead. Fixes: 5d62c183f9e9 ("nohz: Prevent a timer interrupt storm in tick_nohz_stop_sched_tick()") Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com> Acked-by: Frederic Weisbecker <frederic@kernel.org> Cc: bigeasy@linutronix.de Cc: peterz@infradead.org Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20180731161358.29472-1-anna-maria@linutronix.de
* Revert: Unify CLOCK_MONOTONIC and CLOCK_BOOTTIMEThomas Gleixner2018-04-261-9/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Revert commits 92af4dcb4e1c ("tracing: Unify the "boot" and "mono" tracing clocks") 127bfa5f4342 ("hrtimer: Unify MONOTONIC and BOOTTIME clock behavior") 7250a4047aa6 ("posix-timers: Unify MONOTONIC and BOOTTIME clock behavior") d6c7270e913d ("timekeeping: Remove boot time specific code") f2d6fdbfd238 ("Input: Evdev - unify MONOTONIC and BOOTTIME clock behavior") d6ed449afdb3 ("timekeeping: Make the MONOTONIC clock behave like the BOOTTIME clock") 72199320d49d ("timekeeping: Add the new CLOCK_MONOTONIC_ACTIVE clock") As stated in the pull request for the unification of CLOCK_MONOTONIC and CLOCK_BOOTTIME, it was clear that we might have to revert the change. As reported by several folks systemd and other applications rely on the documented behaviour of CLOCK_MONOTONIC on Linux and break with the above changes. After resume daemons time out and other timeout related issues are observed. Rafael compiled this list: * systemd kills daemons on resume, after >WatchdogSec seconds of suspending (Genki Sky). [Verified that that's because systemd uses CLOCK_MONOTONIC and expects it to not include the suspend time.] * systemd-journald misbehaves after resume: systemd-journald[7266]: File /var/log/journal/016627c3c4784cd4812d4b7e96a34226/system.journal corrupted or uncleanly shut down, renaming and replacing. (Mike Galbraith). * NetworkManager reports "networking disabled" and networking is broken after resume 50% of the time (Pavel). [May be because of systemd.] * MATE desktop dims the display and starts the screensaver right after system resume (Pavel). * Full system hang during resume (me). [May be due to systemd or NM or both.] That happens on debian and open suse systems. It's sad, that these problems were neither catched in -next nor by those folks who expressed interest in this change. Reported-by: Rafael J. Wysocki <rjw@rjwysocki.net> Reported-by: Genki Sky <sky@genki.is>, Reported-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kevin Easton <kevin@guarana.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mark Salyzyn <salyzyn@android.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org>
* tick/sched: Do not mess with an enqueued hrtimerThomas Gleixner2018-04-261-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Kaike reported that in tests rdma hrtimers occasionaly stopped working. He did great debugging, which provided enough context to decode the problem. CPU 3 CPU 2 idle start sched_timer expires = 712171000000 queue->next = sched_timer start rdmavt timer. expires = 712172915662 lock(baseof(CPU3)) tick_nohz_stop_tick() tick = 716767000000 timerqueue_add(tmr) hrtimer_set_expires(sched_timer, tick); sched_timer->expires = 716767000000 <---- FAIL if (tmr->expires < queue->next->expires) hrtimer_start(sched_timer) queue->next = tmr; lock(baseof(CPU3)) unlock(baseof(CPU3)) timerqueue_remove() timerqueue_add() ts->sched_timer is queued and queue->next is pointing to it, but then ts->sched_timer.expires is modified. This not only corrupts the ordering of the timerqueue RB tree, it also makes CPU2 see the new expiry time of timerqueue->next->expires when checking whether timerqueue->next needs to be updated. So CPU2 sees that the rdma timer is earlier than timerqueue->next and sets the rdma timer as new next. Depending on whether it had also seen the new time at RB tree enqueue, it might have queued the rdma timer at the wrong place and then after removing the sched_timer the RB tree is completely hosed. The problem was introduced with a commit which tried to solve inconsistency between the hrtimer in the tick_sched data and the underlying hardware clockevent. It split out hrtimer_set_expires() to store the new tick time in both the NOHZ and the NOHZ + HIGHRES case, but missed the fact that in the NOHZ + HIGHRES case the hrtimer might still be queued. Use hrtimer_start(timer, tick...) for the NOHZ + HIGHRES case which sets timer->expires after canceling the timer and move the hrtimer_set_expires() invocation into the NOHZ only code path which is not affected as it merily uses the hrtimer as next event storage so code pathes can be shared with the NOHZ + HIGHRES case. Fixes: d4af6d933ccf ("nohz: Fix spurious warning when hrtimer and clockevent get out of sync") Reported-by: "Wan Kaike" <kaike.wan@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Frederic Weisbecker <frederic@kernel.org> Cc: "Marciniszyn Mike" <mike.marciniszyn@intel.com> Cc: Anna-Maria Gleixner <anna-maria@linutronix.de> Cc: linux-rdma@vger.kernel.org Cc: "Dalessandro Dennis" <dennis.dalessandro@intel.com> Cc: "Fleck John" <john.fleck@intel.com> Cc: stable@vger.kernel.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: "Weiny Ira" <ira.weiny@intel.com> Cc: "linux-rdma@vger.kernel.org" Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1804241637390.1679@nanos.tec.linutronix.de Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1804242119210.1597@nanos.tec.linutronix.de
generated by cgit (git 2.34.1) at 2025-02-24 22:04:53 +0000