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* Merge tag 'timers-core-2024-11-18' of ↵Linus Torvalds4 days1-2/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner: "A rather large update for timekeeping and timers: - The final step to get rid of auto-rearming posix-timers posix-timers are currently auto-rearmed by the kernel when the signal of the timer is ignored so that the timer signal can be delivered once the corresponding signal is unignored. This requires to throttle the timer to prevent a DoS by small intervals and keeps the system pointlessly out of low power states for no value. This is a long standing non-trivial problem due to the lock order of posix-timer lock and the sighand lock along with life time issues as the timer and the sigqueue have different life time rules. Cure this by: - Embedding the sigqueue into the timer struct to have the same life time rules. Aside of that this also avoids the lookup of the timer in the signal delivery and rearm path as it's just a always valid container_of() now. - Queuing ignored timer signals onto a seperate ignored list. - Moving queued timer signals onto the ignored list when the signal is switched to SIG_IGN before it could be delivered. - Walking the ignored list when SIG_IGN is lifted and requeue the signals to the actual signal lists. This allows the signal delivery code to rearm the timer. This also required to consolidate the signal delivery rules so they are consistent across all situations. With that all self test scenarios finally succeed. - Core infrastructure for VFS multigrain timestamping This is required to allow the kernel to use coarse grained time stamps by default and switch to fine grained time stamps when inode attributes are actively observed via getattr(). These changes have been provided to the VFS tree as well, so that the VFS specific infrastructure could be built on top. - Cleanup and consolidation of the sleep() infrastructure - Move all sleep and timeout functions into one file - Rework udelay() and ndelay() into proper documented inline functions and replace the hardcoded magic numbers by proper defines. - Rework the fsleep() implementation to take the reality of the timer wheel granularity on different HZ values into account. Right now the boundaries are hard coded time ranges which fail to provide the requested accuracy on different HZ settings. - Update documentation for all sleep/timeout related functions and fix up stale documentation links all over the place - Fixup a few usage sites - Rework of timekeeping and adjtimex(2) to prepare for multiple PTP clocks A system can have multiple PTP clocks which are participating in seperate and independent PTP clock domains. So far the kernel only considers the PTP clock which is based on CLOCK TAI relevant as that's the clock which drives the timekeeping adjustments via the various user space daemons through adjtimex(2). The non TAI based clock domains are accessible via the file descriptor based posix clocks, but their usability is very limited. They can't be accessed fast as they always go all the way out to the hardware and they cannot be utilized in the kernel itself. As Time Sensitive Networking (TSN) gains traction it is required to provide fast user and kernel space access to these clocks. The approach taken is to utilize the timekeeping and adjtimex(2) infrastructure to provide this access in a similar way how the kernel provides access to clock MONOTONIC, REALTIME etc. Instead of creating a duplicated infrastructure this rework converts timekeeping and adjtimex(2) into generic functionality which operates on pointers to data structures instead of using static variables. This allows to provide time accessors and adjtimex(2) functionality for the independent PTP clocks in a subsequent step. - Consolidate hrtimer initialization hrtimers are set up by initializing the data structure and then seperately setting the callback function for historical reasons. That's an extra unnecessary step and makes Rust support less straight forward than it should be. Provide a new set of hrtimer_setup*() functions and convert the core code and a few usage sites of the less frequently used interfaces over. The bulk of the htimer_init() to hrtimer_setup() conversion is already prepared and scheduled for the next merge window. - Drivers: - Ensure that the global timekeeping clocksource is utilizing the cluster 0 timer on MIPS multi-cluster systems. Otherwise CPUs on different clusters use their cluster specific clocksource which is not guaranteed to be synchronized with other clusters. - Mostly boring cleanups, fixes, improvements and code movement" * tag 'timers-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (140 commits) posix-timers: Fix spurious warning on double enqueue versus do_exit() clocksource/drivers/arm_arch_timer: Use of_property_present() for non-boolean properties clocksource/drivers/gpx: Remove redundant casts clocksource/drivers/timer-ti-dm: Fix child node refcount handling dt-bindings: timer: actions,owl-timer: convert to YAML clocksource/drivers/ralink: Add Ralink System Tick Counter driver clocksource/drivers/mips-gic-timer: Always use cluster 0 counter as clocksource clocksource/drivers/timer-ti-dm: Don't fail probe if int not found clocksource/drivers:sp804: Make user selectable clocksource/drivers/dw_apb: Remove unused dw_apb_clockevent functions hrtimers: Delete hrtimer_init_on_stack() alarmtimer: Switch to use hrtimer_setup() and hrtimer_setup_on_stack() io_uring: Switch to use hrtimer_setup_on_stack() sched/idle: Switch to use hrtimer_setup_on_stack() hrtimers: Delete hrtimer_init_sleeper_on_stack() wait: Switch to use hrtimer_setup_sleeper_on_stack() timers: Switch to use hrtimer_setup_sleeper_on_stack() net: pktgen: Switch to use hrtimer_setup_sleeper_on_stack() futex: Switch to use hrtimer_setup_sleeper_on_stack() fs/aio: Switch to use hrtimer_setup_sleeper_on_stack() ...
| * clockevents: Shutdown and unregister current clockevents at CPUHP_AP_TICK_DYINGFrederic Weisbecker2024-10-311-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The way the clockevent devices are finally stopped while a CPU is offlining is currently chaotic. The layout being by order: 1) tick_sched_timer_dying() stops the tick and the underlying clockevent but only for oneshot case. The periodic tick and its related clockevent still runs. 2) tick_broadcast_offline() detaches and stops the per-cpu oneshot broadcast and append it to the released list. 3) Some individual clockevent drivers stop the clockevents (a second time if the tick is oneshot) 4) Once the CPU is dead, a control CPU remotely detaches and stops (a 3rd time if oneshot mode) the CPU clockevent and adds it to the released list. 5) The released list containing the broadcast device released on step 2) and the remotely detached clockevent from step 4) are unregistered. These random events can be factorized if the current clockevent is detached and stopped by the dying CPU at the generic layer, that is from the dying CPU: a) Stop the tick b) Stop/detach the underlying per-cpu oneshot broadcast clockevent c) Stop/detach the underlying clockevent d) Release / unregister the clockevents from b) and c) e) Release / unregister the remaining clockevents from the dying CPU. This part could be performed by the dying CPU This way the drivers and the tick layer don't need to care about clockevent operations during cpuhotplug down. This also unifies the tick behaviour on offline CPUs between oneshot and periodic modes, avoiding offline ticks altogether for sanity. Adopt the simplification. [ tglx: Remove the WARN_ON() in clockevents_register_device() as that is called from an upcoming CPU before the CPU is marked online ] Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20241029125451.54574-3-frederic@kernel.org
* | posix-cpu-timers: Clear TICK_DEP_BIT_POSIX_TIMER on cloneBenjamin Segall2024-10-271-0/+8
|/ | | | | | | | | | | | | | | | | | | | | | | | | | When cloning a new thread, its posix_cputimers are not inherited, and are cleared by posix_cputimers_init(). However, this does not clear the tick dependency it creates in tsk->tick_dep_mask, and the handler does not reach the code to clear the dependency if there were no timers to begin with. Thus if a thread has a cputimer running before clone/fork, all descendants will prevent nohz_full unless they create a cputimer of their own. Fix this by entirely clearing the tick_dep_mask in copy_process(). (There is currently no inherited state that needs a tick dependency) Process-wide timers do not have this problem because fork does not copy signal_struct as a baseline, it creates one from scratch. Fixes: b78783000d5c ("posix-cpu-timers: Migrate to use new tick dependency mask model") Signed-off-by: Ben Segall <bsegall@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/xm26o737bq8o.fsf@google.com
* tick: Remove unnused tick_nohz_get_idle_calls()Christian Loehle2024-06-211-1/+0
| | | | | | | | | | | | The function returns the idle calls counter for the current cpu and therefore usually isn't what the caller wants. It is unnused since commit 466a2b42d676 ("cpufreq: schedutil: Use idle_calls counter of the remote CPU") Signed-off-by: Christian Loehle <christian.loehle@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20240617161615.49309-1-christian.loehle@arm.com
* Merge tag 'x86-core-2024-03-11' of ↵Linus Torvalds2024-03-111-0/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull core x86 updates from Ingo Molnar: - The biggest change is the rework of the percpu code, to support the 'Named Address Spaces' GCC feature, by Uros Bizjak: - This allows C code to access GS and FS segment relative memory via variables declared with such attributes, which allows the compiler to better optimize those accesses than the previous inline assembly code. - The series also includes a number of micro-optimizations for various percpu access methods, plus a number of cleanups of %gs accesses in assembly code. - These changes have been exposed to linux-next testing for the last ~5 months, with no known regressions in this area. - Fix/clean up __switch_to()'s broken but accidentally working handling of FPU switching - which also generates better code - Propagate more RIP-relative addressing in assembly code, to generate slightly better code - Rework the CPU mitigations Kconfig space to be less idiosyncratic, to make it easier for distros to follow & maintain these options - Rework the x86 idle code to cure RCU violations and to clean up the logic - Clean up the vDSO Makefile logic - Misc cleanups and fixes * tag 'x86-core-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits) x86/idle: Select idle routine only once x86/idle: Let prefer_mwait_c1_over_halt() return bool x86/idle: Cleanup idle_setup() x86/idle: Clean up idle selection x86/idle: Sanitize X86_BUG_AMD_E400 handling sched/idle: Conditionally handle tick broadcast in default_idle_call() x86: Increase brk randomness entropy for 64-bit systems x86/vdso: Move vDSO to mmap region x86/vdso/kbuild: Group non-standard build attributes and primary object file rules together x86/vdso: Fix rethunk patching for vdso-image-{32,64}.o x86/retpoline: Ensure default return thunk isn't used at runtime x86/vdso: Use CONFIG_COMPAT_32 to specify vdso32 x86/vdso: Use $(addprefix ) instead of $(foreach ) x86/vdso: Simplify obj-y addition x86/vdso: Consolidate targets and clean-files x86/bugs: Rename CONFIG_RETHUNK => CONFIG_MITIGATION_RETHUNK x86/bugs: Rename CONFIG_CPU_SRSO => CONFIG_MITIGATION_SRSO x86/bugs: Rename CONFIG_CPU_IBRS_ENTRY => CONFIG_MITIGATION_IBRS_ENTRY x86/bugs: Rename CONFIG_CPU_UNRET_ENTRY => CONFIG_MITIGATION_UNRET_ENTRY x86/bugs: Rename CONFIG_SLS => CONFIG_MITIGATION_SLS ...
| * sched/idle: Conditionally handle tick broadcast in default_idle_call()Thomas Gleixner2024-03-011-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The x86 architecture has an idle routine for AMD CPUs which are affected by erratum 400. On the affected CPUs the local APIC timer stops in the C1E halt state. It therefore requires tick broadcasting. The invocation of tick_broadcast_enter()/exit() from this function violates the RCU constraints because it can end up in lockdep or tracing, which rightfully triggers a warning. tick_broadcast_enter()/exit() must be invoked before ct_cpuidle_enter() and after ct_cpuidle_exit() in default_idle_call(). Add a static branch conditional invocation of tick_broadcast_enter()/exit() into this function to allow X86 to replace the AMD specific idle code. It's guarded by a config switch which will be selected by x86. Otherwise it's a NOOP. Reported-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20240229142248.266708822@linutronix.de
* | Merge tag 'x86_cache_for_v6.9_rc1' of ↵Linus Torvalds2024-03-111-1/+8
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull resource control updates from Borislav Petkov: - Rework different aspects of the resctrl code like adding arch-specific accessors and splitting the locking, in order to accomodate ARM's MPAM implementation of hw resource control and be able to use the same filesystem control interface like on x86. Work by James Morse - Improve the memory bandwidth throttling heuristic to handle workloads with not too regular load levels which end up penalized unnecessarily - Use CPUID to detect the memory bandwidth enforcement limit on AMD - The usual set of fixes * tag 'x86_cache_for_v6.9_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (30 commits) x86/resctrl: Remove lockdep annotation that triggers false positive x86/resctrl: Separate arch and fs resctrl locks x86/resctrl: Move domain helper migration into resctrl_offline_cpu() x86/resctrl: Add CPU offline callback for resctrl work x86/resctrl: Allow overflow/limbo handlers to be scheduled on any-but CPU x86/resctrl: Add CPU online callback for resctrl work x86/resctrl: Add helpers for system wide mon/alloc capable x86/resctrl: Make rdt_enable_key the arch's decision to switch x86/resctrl: Move alloc/mon static keys into helpers x86/resctrl: Make resctrl_mounted checks explicit x86/resctrl: Allow arch to allocate memory needed in resctrl_arch_rmid_read() x86/resctrl: Allow resctrl_arch_rmid_read() to sleep x86/resctrl: Queue mon_event_read() instead of sending an IPI x86/resctrl: Add cpumask_any_housekeeping() for limbo/overflow x86/resctrl: Move CLOSID/RMID matching and setting to use helpers x86/resctrl: Allocate the cleanest CLOSID by searching closid_num_dirty_rmid x86/resctrl: Use __set_bit()/__clear_bit() instead of open coding x86/resctrl: Track the number of dirty RMID a CLOSID has x86/resctrl: Allow RMID allocation to be scoped by CLOSID x86/resctrl: Access per-rmid structures by index ...
| * | tick/nohz: Move tick_nohz_full_mask declaration outside the #ifdefJames Morse2024-02-161-1/+8
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | tick_nohz_full_mask lists the CPUs that are nohz_full. This is only needed when CONFIG_NO_HZ_FULL is defined. tick_nohz_full_cpu() allows a specific CPU to be tested against the mask, and evaluates to false when CONFIG_NO_HZ_FULL is not defined. The resctrl code needs to pick a CPU to run some work on, a new helper prefers housekeeping CPUs by examining the tick_nohz_full_mask. Hiding the declaration behind #ifdef CONFIG_NO_HZ_FULL forces all the users to be behind an #ifdef too. Move the tick_nohz_full_mask declaration, this lets callers drop the #ifdef, and guard access to tick_nohz_full_mask with IS_ENABLED() or something like tick_nohz_full_cpu(). The definition does not need to be moved as any callers should be removed at compile time unless CONFIG_NO_HZ_FULL is defined. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Shaopeng Tan <tan.shaopeng@fujitsu.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Reinette Chatre <reinette.chatre@intel.com> # for resctrl dependency Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com> Tested-by: Peter Newman <peternewman@google.com> Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64 Link: https://lore.kernel.org/r/20240213184438.16675-2-james.morse@arm.com Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
* | tick: Assume timekeeping is correctly handed over upon last offline idle callFrederic Weisbecker2024-02-261-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The timekeeping duty is handed over from the outgoing CPU on stop machine, then the oneshot tick is stopped right after. Therefore it's guaranteed that the current CPU isn't the timekeeper upon its last call to idle. Besides, calling tick_nohz_idle_stop_tick() while the dying CPU goes into idle suggests that the tick is going to be stopped while it is actually stopped already from the appropriate CPU hotplug state. Remove the confusing call and the obsolete case handling and convert it to a sanity check that verifies the above assumption. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20240225225508.11587-16-frederic@kernel.org
* | tick: Move broadcast cancellation up to CPUHP_AP_TICK_DYINGFrederic Weisbecker2024-02-261-6/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The broadcast shutdown code is executed through a random explicit call within stop machine from the outgoing CPU. However the tick broadcast is a midware between the tick callback and the clocksource, therefore it makes more sense to shut it down after the tick callback and before the clocksource drivers. Move it instead to the common tick shutdown CPU hotplug state where related operations can be ordered from highest to lowest level. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20240225225508.11587-10-frederic@kernel.org
* | tick: Start centralizing tick related CPU hotplug operationsFrederic Weisbecker2024-02-261-2/+6
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | During the CPU offlining process, the various timer tick features are shut down from scattered places, sometimes from teardown callbacks on stop machine, sometimes through explicit calls, sometimes from the control CPU after the CPU died. The reason why these shutdown operations are spread around is not always clear and it makes the tick lifecycle hard to follow. The tick should be shut down in order from highest to lowest level: On stop machine from the dying CPU (high-level): 1) Hand-over the timekeeping duty (tick_handover_do_timer()) 2) Cancel the tick implementation called by the clockevent callback (tick_cancel_sched_timer()) 3) Shutdown broadcasting (tick_offline_cpu() / tick_broadcast_offline()) On stop machine from the dying CPU (low-level): 4) Shutdown clockevents drivers (CPUHP_AP_*_TIMER_STARTING states) From the control CPU after the CPU died (low-level): 5) Shutdown/unregister/cleanup clockevents for the dead CPU (tick_cleanup_dead_cpu()) Instead the current order is 2, 4 (both from CPU hotplug states), then 1 and 3 through direct calls. This layout and order don't make much sense. The operations 1, 2, 3 should be gathered together and in order. Sort this situation with creating a new TICK shut-down CPU hotplug state and start with introducing the timekeeping duty hand-over there. The state must precede hrtimers migration because the tick hrtimer will be stopped from it in a further patch. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20240225225508.11587-8-frederic@kernel.org
* tick/nohz: Remove unused tick_nohz_idle_stop_tick_protected()Xueshi Hu2023-09-271-10/+0
| | | | | | | | | | | All the caller has been removed since commit 336f560a8917 ("x86/xen: don't let xen_pv_play_dead() return") Signed-off-by: Xueshi Hu <xueshi.hu@smartx.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20230912104406.312185-5-frederic@kernel.org
* tick/nohz: Fix cpu_is_hotpluggable() by checking with nohz subsystemJoel Fernandes (Google)2023-04-051-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | For CONFIG_NO_HZ_FULL systems, the tick_do_timer_cpu cannot be offlined. However, cpu_is_hotpluggable() still returns true for those CPUs. This causes torture tests that do offlining to end up trying to offline this CPU causing test failures. Such failure happens on all architectures. Fix the repeated error messages thrown by this (even if the hotplug errors are harmless) by asking the opinion of the nohz subsystem on whether the CPU can be hotplugged. [ Apply Frederic Weisbecker feedback on refactoring tick_nohz_cpu_down(). ] For drivers/base/ portion: Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Frederic Weisbecker <frederic@kernel.org> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Zhouyi Zhou <zhouzhouyi@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: rcu <rcu@vger.kernel.org> Cc: stable@vger.kernel.org Fixes: 2987557f52b9 ("driver-core/cpu: Expose hotpluggability to the rest of the kernel") Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
* Merge tag 'timers-nohz-2021-06-28' of ↵Linus Torvalds2021-06-281-11/+15
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: Change signal tick dependency to wake up CPUs of member tasksMarcelo Tosatti2021-05-131-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | 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: Evaluate the CPU expression after the static keyPeter Zijlstra2021-05-131-7/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When tick_nohz_full_cpu() is called with smp_processor_id(), the latter is unconditionally evaluated whether the static key is on or off. It is not necessary in the off-case though, so make sure the cpu expression is executed at the last moment. Illustrate with the following test function: int tick_nohz_test(void) { return tick_nohz_full_cpu(smp_processor_id()); } The resulting code before was: mov %gs:0x7eea92d1(%rip),%eax # smp_processor_id() fetch nopl 0x0(%rax,%rax,1) xor %eax,%eax retq cmpb $0x0,0x29d393a(%rip) # <tick_nohz_full_running> je tick_nohz_test+0x29 # jump to below eax clear mov %eax,%eax bt %rax,0x29d3936(%rip) # <tick_nohz_full_mask> setb %al movzbl %al,%eax retq xor %eax,%eax retq Now it becomes: nopl 0x0(%rax,%rax,1) xor %eax,%eax retq cmpb $0x0,0x29d3871(%rip) # <tick_nohz_full_running> je tick_nohz_test+0x29 # jump to below eax clear mov %gs:0x7eea91f0(%rip),%eax # smp_processor_id() fetch, after static key mov %eax,%eax bt %rax,0x29d3866(%rip) # <tick_nohz_full_mask> setb %al movzbl %al,%eax retq xor %eax,%eax retq 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/20210512232924.150322-2-frederic@kernel.org
* | tick/nohz: Only check for RCU deferred wakeup on user/guest entry when neededFrederic Weisbecker2021-05-311-0/+7
|/ | | | | | | | | | | | | | | | | | | 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
* rcu: Enable tick for nohz_full CPUs slow to provide expedited QSPaul E. McKenney2019-12-091-1/+4
| | | | | | | | | | | | | | | | | | | An expedited grace period can be stalled by a nohz_full CPU looping in kernel context. This possibility is currently handled by some carefully crafted checks in rcu_read_unlock_special() that enlist help from ksoftirqd when permitted by the scheduler. However, it is exactly these checks that require the scheduler avoid holding any of its rq or pi locks across rcu_read_unlock() without also having held them across the entire RCU read-side critical section. It would therefore be very nice if expedited grace periods could handle nohz_full CPUs looping in kernel context without such checks. This commit therefore adds code to the expedited grace period's wait and cleanup code that forces the scheduler-clock interrupt on for CPUs that fail to quickly supply a quiescent state. "Quickly" is currently a hard-coded single-jiffy delay. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
* Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds2019-11-261-1/+6
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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() ...
| * nohz: Add TICK_DEP_BIT_RCUFrederic Weisbecker2019-10-051-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | context_tracking: Rename context_tracking_is_enabled() => ↵Frederic Weisbecker2019-10-291-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | context_tracking_enabled() Remove the superfluous "is" in the middle of the name. We want to standardize the naming so that it can be expanded through suffixes: context_tracking_enabled() context_tracking_enabled_cpu() context_tracking_enabled_this_cpu() 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/20191016025700.31277-6-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge tag 'pm-5.2-rc1' of ↵Linus Torvalds2019-05-061-1/+6
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 Hansson2019-04-101-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | tick: Remove outgoing CPU from broadcast masksThomas Gleixner2019-03-231-0/+6
|/ | | | | | | | | | | | | | | | | | | | | Valentin reported that unplugging a CPU occasionally results in a warning in the tick broadcast code which is triggered when an offline CPU is in the broadcast mask. This happens because the outgoing CPU is not removing itself from the broadcast masks, especially not from the broadcast_force_mask. The removal happens on the control CPU after the outgoing CPU is dead. It's a long standing issue, but the warning is harmless. Rework the hotplug mechanism so that the outgoing CPU removes itself from the broadcast masks after disabling interrupts and removing itself from the online mask. Reported-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Valentin Schneider <valentin.schneider@arm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1903211540180.1784@nanos.tec.linutronix.de
* cpuidle: menu: Refine idle state selection for running tickRafael J. Wysocki2018-04-091-3/+4
| | | | | | | | | | | | | | If the tick isn't stopped, the target residency of the state selected by the menu governor may be greater than the actual time to the next tick and that means lost energy. To avoid that, make tick_nohz_get_sleep_length() return the current time to the next event (before stopping the tick) in addition to the estimated one via an extra pointer argument and make menu_select() use that value to refine the state selection when necessary. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
* sched: idle: Select idle state before stopping the tickRafael J. Wysocki2018-04-091-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In order to address the issue with short idle duration predictions by the idle governor after the scheduler tick has been stopped, reorder the code in cpuidle_idle_call() so that the governor idle state selection runs before tick_nohz_idle_go_idle() and use the "nohz" hint returned by cpuidle_select() to decide whether or not to stop the tick. This isn't straightforward, because menu_select() invokes tick_nohz_get_sleep_length() to get the time to the next timer event and the number returned by the latter comes from __tick_nohz_idle_stop_tick(). Fortunately, however, it is possible to compute that number without actually stopping the tick and with the help of the existing code. Namely, tick_nohz_get_sleep_length() can be made call tick_nohz_next_event(), introduced earlier, to get the time to the next non-highres timer event. If that happens, tick_nohz_next_event() need not be called by __tick_nohz_idle_stop_tick() again. If it turns out that the scheduler tick cannot be stopped going forward or the next timer event is too close for the tick to be stopped, tick_nohz_get_sleep_length() can simply return the time to the next event currently programmed into the corresponding clock event device. In addition to knowing the return value of tick_nohz_next_event(), however, tick_nohz_get_sleep_length() needs to know the time to the next highres timer event, but with the scheduler tick timer excluded, which can be computed with the help of hrtimer_get_next_event(). That minimum of that number and the tick_nohz_next_event() return value is the total time to the next timer event with the assumption that the tick will be stopped. It can be returned to the idle governor which can use it for predicting idle duration (under the assumption that the tick will be stopped) and deciding whether or not it makes sense to stop the tick before putting the CPU into the selected idle state. With the above, the sleep_length field in struct tick_sched is not necessary any more, so drop it. Link: https://bugzilla.kernel.org/show_bug.cgi?id=199227 Reported-by: Doug Smythies <dsmythies@telus.net> Reported-by: Thomas Ilsche <thomas.ilsche@tu-dresden.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
* cpuidle: Return nohz hint from cpuidle_select()Rafael J. Wysocki2018-04-061-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a new pointer argument to cpuidle_select() and to the ->select cpuidle governor callback to allow a boolean value indicating whether or not the tick should be stopped before entering the selected state to be returned from there. Make the ladder governor ignore that pointer (to preserve its current behavior) and make the menu governor return 'false" through it if: (1) the idle exit latency is constrained at 0, or (2) the selected state is a polling one, or (3) the expected idle period duration is within the tick period range. In addition to that, the correction factor computations in the menu governor need to take the possibility that the tick may not be stopped into account to avoid artificially small correction factor values. To that end, add a mechanism to record tick wakeups, as suggested by Peter Zijlstra, and use it to modify the menu_update() behavior when tick wakeup occurs. Namely, if the CPU is woken up by the tick and the return value of tick_nohz_get_sleep_length() is not within the tick boundary, the predicted idle duration is likely too short, so make menu_update() try to compensate for that by updating the governor statistics as though the CPU was idle for a long time. Since the value returned through the new argument pointer of cpuidle_select() is not used by its caller yet, this change by itself is not expected to alter the functionality of the code. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
* sched: idle: Do not stop the tick upfront in the idle loopRafael J. Wysocki2018-04-051-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Push the decision whether or not to stop the tick somewhat deeper into the idle loop. Stopping the tick upfront leads to unpleasant outcomes in case the idle governor doesn't agree with the nohz code on the duration of the upcoming idle period. Specifically, if the tick has been stopped and the idle governor predicts short idle, the situation is bad regardless of whether or not the prediction is accurate. If it is accurate, the tick has been stopped unnecessarily which means excessive overhead. If it is not accurate, the CPU is likely to spend too much time in the (shallow, because short idle has been predicted) idle state selected by the governor [1]. As the first step towards addressing this problem, change the code to make the tick stopping decision inside of the loop in do_idle(). In particular, do not stop the tick in the cpu_idle_poll() code path. Also don't do that in tick_nohz_irq_exit() which doesn't really have enough information on whether or not to stop the tick. Link: https://marc.info/?l=linux-pm&m=150116085925208&w=2 # [1] Link: https://tu-dresden.de/zih/forschung/ressourcen/dateien/projekte/haec/powernightmares.pdf Suggested-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
* time: tick-sched: Reorganize idle tick management codeRafael J. Wysocki2018-04-051-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | Prepare the scheduler tick code for reworking the idle loop to avoid stopping the tick in some cases. The idea is to split the nohz idle entry call to decouple the idle time stats accounting and preparatory work from the actual tick stop code, in order to later be able to delay the tick stop once we reach more power-knowledgeable callers. Move away the tick_nohz_start_idle() invocation from __tick_nohz_idle_enter(), rename the latter to __tick_nohz_idle_stop_tick() and define tick_nohz_idle_stop_tick() as a wrapper around it for calling it from the outside. Make tick_nohz_idle_enter() only call tick_nohz_start_idle() instead of calling the entire __tick_nohz_idle_enter(), add another wrapper disabling and enabling interrupts around tick_nohz_idle_stop_tick() and make the current callers of tick_nohz_idle_enter() call it too to retain their current functionality. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
* nohz: Allow to check if remote CPU tick is stoppedFrederic Weisbecker2018-02-211-0/+2
| | | | | | | | | | | | | | | | | | | This check is racy but provides a good heuristic to determine whether a CPU may need a remote tick or not. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Christoph Lameter <cl@linux.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Cc: Wanpeng Li <kernellwp@gmail.com> Link: http://lkml.kernel.org/r/1519186649-3242-4-git-send-email-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* nohz: Convert tick_nohz_tick_stopped() to boolFrederic Weisbecker2018-02-211-1/+1
| | | | | | | | | | | | | | | | | | | | It makes this function more self-explanatory about what it does and how to use it. Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Christoph Lameter <cl@linux.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Cc: Wanpeng Li <kernellwp@gmail.com> Link: http://lkml.kernel.org/r/1519186649-3242-3-git-send-email-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* cpufreq: schedutil: Use idle_calls counter of the remote CPUJoel Fernandes2017-12-281-0/+1
| | | | | | | | | | | | | | | Since the recent remote cpufreq callback work, its possible that a cpufreq update is triggered from a remote CPU. For single policies however, the current code uses the local CPU when trying to determine if the remote sg_cpu entered idle or is busy. This is incorrect. To remedy this, compare with the nohz tick idle_calls counter of the remote CPU. Fixes: 674e75411fc2 (sched: cpufreq: Allow remote cpufreq callbacks) Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Joel Fernandes <joelaf@google.com> Cc: 4.14+ <stable@vger.kernel.org> # 4.14+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* Merge branch 'linus' into sched/core, to pick up fixesIngo Molnar2017-11-081-0/+1
|\ | | | | | | Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman2017-11-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | sched/isolation: Handle the nohz_full= parameterFrederic Weisbecker2017-10-271-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We want to centralize the isolation management, done by the housekeeping subsystem. Therefore we need to handle the nohz_full= parameter from there. Since nohz_full= so far has involved unbound timers, watchdog, RCU and tilegx NAPI isolation, we keep that default behaviour. nohz_full= will be deprecated in the future. We want to control the isolation features from the isolcpus= parameter. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Christoph Lameter <cl@linux.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Wanpeng Li <kernellwp@gmail.com> Link: http://lkml.kernel.org/r/1509072159-31808-10-git-send-email-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | sched/isolation: Move housekeeping related code to its own fileFrederic Weisbecker2017-10-271-37/+0
|/ | | | | | | | | | | | | | | | | | | | The housekeeping code is currently tied to the NOHZ code. As we are planning to make housekeeping independent from it, start with moving the relevant code to its own file. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Christoph Lameter <cl@linux.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Wanpeng Li <kernellwp@gmail.com> Link: http://lkml.kernel.org/r/1509072159-31808-2-git-send-email-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* cpufreq: schedutil: Avoid reducing frequency of busy CPUs prematurelyRafael J. Wysocki2017-03-231-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The way the schedutil governor uses the PELT metric causes it to underestimate the CPU utilization in some cases. That can be easily demonstrated by running kernel compilation on a Sandy Bridge Intel processor, running turbostat in parallel with it and looking at the values written to the MSR_IA32_PERF_CTL register. Namely, the expected result would be that when all CPUs were 100% busy, all of them would be requested to run in the maximum P-state, but observation shows that this clearly isn't the case. The CPUs run in the maximum P-state for a while and then are requested to run slower and go back to the maximum P-state after a while again. That causes the actual frequency of the processor to visibly oscillate below the sustainable maximum in a jittery fashion which clearly is not desirable. That has been attributed to CPU utilization metric updates on task migration that cause the total utilization value for the CPU to be reduced by the utilization of the migrated task. If that happens, the schedutil governor may see a CPU utilization reduction and will attempt to reduce the CPU frequency accordingly right away. That may be premature, though, for example if the system is generally busy and there are other runnable tasks waiting to be run on that CPU already. This is unlikely to be an issue on systems where cpufreq policies are shared between multiple CPUs, because in those cases the policy utilization is computed as the maximum of the CPU utilization values over the whole policy and if that turns out to be low, reducing the frequency for the policy most likely is a good idea anyway. On systems with one CPU per policy, however, it may affect performance adversely and even lead to increased energy consumption in some cases. On those systems it may be addressed by taking another utilization metric into consideration, like whether or not the CPU whose frequency is about to be reduced has been idle recently, because if that's not the case, the CPU is likely to be busy in the near future and its frequency should not be reduced. To that end, use the counter of idle calls in the timekeeping code. Namely, make the schedutil governor look at that counter for the current CPU every time before its frequency is about to be reduced. If the counter has not changed since the previous iteration of the governor computations for that CPU, the CPU has been busy for all that time and its frequency should not be decreased, so if the new frequency would be lower than the one set previously, the governor will skip the frequency update. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Joel Fernandes <joelaf@google.com>
* ktime: Get rid of the unionThomas Gleixner2016-12-251-3/+1
| | | | | | | | | | | | | | | ktime is a union because the initial implementation stored the time in scalar nanoseconds on 64 bit machine and in a endianess optimized timespec variant for 32bit machines. The Y2038 cleanup removed the timespec variant and switched everything to scalar nanoseconds. The union remained, but become completely pointless. Get rid of the union and just keep ktime_t as simple typedef of type s64. The conversion was done with coccinelle and some manual mopping up. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org>
* param: convert some "on"/"off" users to strtoboolKees Cook2016-03-171-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | This changes several users of manual "on"/"off" parsing to use strtobool. Some side-effects: - these uses will now parse y/n/1/0 meaningfully too - the early_param uses will now bubble up parse errors Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Amitkumar Karwar <akarwar@marvell.com> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Joe Perches <joe@perches.com> Cc: Kalle Valo <kvalo@codeaurora.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Nishant Sarmukadam <nishants@marvell.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Steve French <sfrench@samba.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* posix-cpu-timers: Migrate to use new tick dependency mask modelFrederic Weisbecker2016-03-021-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | Instead of providing asynchronous checks for the nohz subsystem to verify posix cpu timers tick dependency, migrate the latter to the new mask. In order to keep track of the running timers and expose the tick dependency accordingly, we must probe the timers queuing and dequeuing on threads and process lists. Unfortunately it implies both task and signal level dependencies. We should be able to further optimize this and merge all that on the task level dependency, at the cost of a bit of complexity and may be overhead. Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* perf: Migrate perf to use new tick dependency mask modelFrederic Weisbecker2016-03-021-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | Instead of providing asynchronous checks for the nohz subsystem to verify perf event tick dependency, migrate perf to the new mask. Perf needs the tick for two situations: 1) Freq events. We could set the tick dependency when those are installed on a CPU context. But setting a global dependency on top of the global freq events accounting is much easier. If people want that to be optimized, we can still refine that on the per-CPU tick dependency level. This patch dooesn't change the current behaviour anyway. 2) Throttled events: this is a per-cpu dependency. Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* nohz: Use enum code for tick stop failure tracing messageFrederic Weisbecker2016-03-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | It makes nohz tracing more lightweight, standard and easier to parse. Examples: user_loop-2904 [007] d..1 517.701126: tick_stop: success=1 dependency=NONE user_loop-2904 [007] dn.1 518.021181: tick_stop: success=0 dependency=SCHED posix_timers-6142 [007] d..1 1739.027400: tick_stop: success=0 dependency=POSIX_TIMER user_loop-5463 [007] dN.1 1185.931939: tick_stop: success=0 dependency=PERF_EVENTS Suggested-by: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* nohz: New tick dependency maskFrederic Weisbecker2016-03-021-0/+92
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The tick dependency is evaluated on every IRQ and context switch. This consists is a batch of checks which determine whether it is safe to stop the tick or not. These checks are often split in many details: posix cpu timers, scheduler, sched clock, perf events.... each of which are made of smaller details: posix cpu timer involves checking process wide timers then thread wide timers. Perf involves checking freq events then more per cpu details. Checking these informations asynchronously every time we update the full dynticks state bring avoidable overhead and a messy layout. Let's introduce instead tick dependency masks: one for system wide dependency (unstable sched clock, freq based perf events), one for CPU wide dependency (sched, throttling perf events), and task/signal level dependencies (posix cpu timers). The subsystems are responsible for setting and clearing their dependency through a set of APIs that will take care of concurrent dependency mask modifications and kick targets to restart the relevant CPU tick whenever needed. This new dependency engine stays beside the old one until all subsystems having a tick dependency are converted to it. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Suggested-by: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* time: nohz: Expose tick_nohz_enabledJean Delvare2016-01-151-0/+2
| | | | | | | | The cpuidle subsystem needs it. Signed-off-by: Jean Delvare <jdelvare@suse.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* nohz: Affine unpinned timers to housekeepersVatika Harlalka2015-09-021-0/+9
| | | | | | | | | | | | | | | | | | | | | | The problem addressed in this patch is about affining unpinned timers. Adaptive or Full Dynticks CPUs are currently disturbed by unnecessary jitter due to firing of such timers on them. This patch will affine timers to online CPUs which are not full dynticks in NOHZ_FULL configured systems. It should not introduce overhead in nohz full off case due to static keys. Signed-off-by: Vatika Harlalka <vatikaharlalka@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1441119060-2230-2-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* nohz: Remove useless argument on tick_nohz_task_switch()Frederic Weisbecker2015-07-291-4/+4
| | | | | | | | | | | | | Leftover from early code. Cc: Christoph Lameter <cl@linux.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* nohz: Restart nohz full tick from irq exitFrederic Weisbecker2015-07-291-8/+0
| | | | | | | | | | | | | | | | | | | | | | Restart the tick when necessary from the irq exit path. It makes nohz full more flexible, simplify the related IPIs and doesn't bring significant overhead on irq exit. In a longer term view, it will allow us to piggyback the nohz kick on the scheduler IPI in the future instead of sending a dedicated IPI that often doubles the scheduler IPI on task wakeup. This will require more changes though including careful review of resched_curr() callers to include nohz full needs. Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* nohz: Prevent tilegx network driver interruptsChris Metcalf2015-07-291-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | Normally the tilegx networking shim sends irqs to all the cores to distribute the load of processing incoming-packet interrupts, so that you can get to multiple Gb's of traffic inbound. However, in nohz_full mode we don't want to interrupt the nohz_full cores by default, so we limit the set of cores we use to only the online housekeeping cores. To make client code easier to read, we introduce a new nohz_full accessor, housekeeping_cpumask(), which returns a pointer to the housekeeping_mask if nohz_full is enabled, and otherwise returns the cpu_possible_mask. Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* tick/broadcast: Unbreak CONFIG_GENERIC_CLOCKEVENTS=n buildThomas Gleixner2015-07-071-0/+7
| | | | | | | | | | | | | Making tick_broadcast_oneshot_control() independent from CONFIG_GENERIC_CLOCKEVENTS_BROADCAST broke the build for CONFIG_GENERIC_CLOCKEVENTS=n because the function is not defined there. Provide a proper stub inline. Fixes: f32dd1170511 'tick/broadcast: Make idle check independent from mode and config' Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* tick/broadcast: Make idle check independent from mode and configThomas Gleixner2015-07-071-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently the broadcast busy check, which prevents the idle code from going into deep idle, works only in one shot mode. If NOHZ and HIGHRES are off (config or command line) there is no sanity check at all, so under certain conditions cpus are allowed to go into deep idle, where the local timer stops, and are not woken up again because there is no broadcast timer installed or a hrtimer based broadcast device is not evaluated. Move tick_broadcast_oneshot_control() into the common code and provide proper subfunctions for the various config combinations. The common check in tick_broadcast_oneshot_control() is for the C3STOP misfeature flag of the local clock event device. If its not set, idle can proceed. If set, further checks are necessary. Provide checks for the trivial cases: - If broadcast is disabled in the config, then return busy - If oneshot mode (NOHZ/HIGHES) is disabled in the config, return busy if the broadcast device is hrtimer based. - If oneshot mode is enabled in the config call the original tick_broadcast_oneshot_control() function. That function needs extra checks which will be implemented in seperate patches. [ Split out from a larger combo patch ] Reported-and-tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
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