Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH v3]PM/Sleep: Timer quiesce in freeze state | Date | Mon, 19 Jan 2015 16:24:48 +0100 |
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On Wednesday, January 14, 2015 08:24:04 AM Li, Aubrey wrote: > Happy New Year, can you please take a look at this patch now?
Thomas, Peter, any comments?
> On 2014/12/9 11:01, Li, Aubrey wrote: > > The patch is based on v3.18. > > > > Freeze is a general power saving state that processes are frozen, devices > > are suspended and CPUs are in idle state. However, when the system enters > > freeze state, there are a few timers keep ticking and hence consumes more > > power unnecessarily. The observed timer events in freeze state are: > > - tick_sched_timer > > - watchdog lockup detector > > - realtime scheduler period timer > > > > The system power consumption in freeze state will be reduced significantly > > if we quiesce these timers. > > > > The patch is tested on: > > - Sandybrdige-EP system, both RTC alarm and power button are able to wake > > the system up from freeze state. > > - HP laptop EliteBook 8460p, both RTC alarm and power button are able to > > wake the system up from freeze state. > > - Baytrail-T(ASUS_T100) platform, power button is able to wake the system > > up from freeze state. > > > > Suggested-by: Thomas Gleixner <tglx@linutronix.de> > > Signed-off-by: Aubrey Li <aubrey.li@linux.intel.com> > > Cc: Peter Zijlstra <peterz@infradead.org> > > Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > Cc: Len Brown <len.brown@intel.com> > > Cc: Alan Cox <alan@linux.intel.com> > > --- > > drivers/cpuidle/cpuidle.c | 13 ++++++++ > > include/linux/clockchips.h | 4 +++ > > include/linux/suspend.h | 4 +++ > > include/linux/timekeeping.h | 2 ++ > > kernel/power/suspend.c | 50 ++++++++++++++++++++++++++--- > > kernel/sched/idle.c | 45 ++++++++++++++++++++++++++ > > kernel/softirq.c | 5 +-- > > kernel/time/clockevents.c | 13 ++++++++ > > kernel/time/tick-common.c | 53 +++++++++++++++++++++++++++++++ > > kernel/time/tick-internal.h | 3 ++ > > kernel/time/timekeeping.c | 77 +++++++++++++++++++++++++++++++++------------ > > 11 files changed, 243 insertions(+), 26 deletions(-) > > > > diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c > > index 125150d..b9a3ada 100644 > > --- a/drivers/cpuidle/cpuidle.c > > +++ b/drivers/cpuidle/cpuidle.c > > @@ -20,6 +20,7 @@ > > #include <linux/hrtimer.h> > > #include <linux/module.h> > > #include <trace/events/power.h> > > +#include <linux/suspend.h> > > > > #include "cpuidle.h" > > > > @@ -119,6 +120,18 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, > > ktime_t time_start, time_end; > > s64 diff; > > > > + /* > > + * under the freeze scenario, the timekeeping is suspended > > + * as well as the clock source device, so we bypass the idle > > + * counter update in freeze idle > > + */ > > + if (in_freeze()) { > > + entered_state = target_state->enter(dev, drv, index); > > + if (!cpuidle_state_is_coupled(dev, drv, entered_state)) > > + local_irq_enable(); > > + return entered_state; > > + } > > + > > trace_cpu_idle_rcuidle(index, dev->cpu); > > time_start = ktime_get(); > > > > diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h > > index 2e4cb67..d118e0b 100644 > > --- a/include/linux/clockchips.h > > +++ b/include/linux/clockchips.h > > @@ -18,6 +18,9 @@ enum clock_event_nofitiers { > > CLOCK_EVT_NOTIFY_BROADCAST_EXIT, > > CLOCK_EVT_NOTIFY_SUSPEND, > > CLOCK_EVT_NOTIFY_RESUME, > > + CLOCK_EVT_NOTIFY_FREEZE_PREPARE, > > + CLOCK_EVT_NOTIFY_FREEZE, > > + CLOCK_EVT_NOTIFY_UNFREEZE, > > CLOCK_EVT_NOTIFY_CPU_DYING, > > CLOCK_EVT_NOTIFY_CPU_DEAD, > > }; > > @@ -95,6 +98,7 @@ enum clock_event_mode { > > */ > > struct clock_event_device { > > void (*event_handler)(struct clock_event_device *); > > + void (*real_handler)(struct clock_event_device *); > > int (*set_next_event)(unsigned long evt, > > struct clock_event_device *); > > int (*set_next_ktime)(ktime_t expires, > > diff --git a/include/linux/suspend.h b/include/linux/suspend.h > > index 3388c1b..86a651c 100644 > > --- a/include/linux/suspend.h > > +++ b/include/linux/suspend.h > > @@ -203,6 +203,8 @@ extern void suspend_set_ops(const struct platform_suspend_ops *ops); > > extern int suspend_valid_only_mem(suspend_state_t state); > > extern void freeze_set_ops(const struct platform_freeze_ops *ops); > > extern void freeze_wake(void); > > +extern bool in_freeze(void); > > +extern bool idle_should_freeze(void); > > > > /** > > * arch_suspend_disable_irqs - disable IRQs for suspend > > @@ -230,6 +232,8 @@ static inline void suspend_set_ops(const struct platform_suspend_ops *ops) {} > > static inline int pm_suspend(suspend_state_t state) { return -ENOSYS; } > > static inline void freeze_set_ops(const struct platform_freeze_ops *ops) {} > > static inline void freeze_wake(void) {} > > +static inline bool in_freeze(void) { return false; } > > +static inline bool idle_should_freeze(void) { return false; } > > #endif /* !CONFIG_SUSPEND */ > > > > /* struct pbe is used for creating lists of pages that should be restored > > diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h > > index 1caa6b0..07957a9 100644 > > --- a/include/linux/timekeeping.h > > +++ b/include/linux/timekeeping.h > > @@ -5,6 +5,8 @@ > > > > void timekeeping_init(void); > > extern int timekeeping_suspended; > > +extern void timekeeping_freeze(void); > > +extern void timekeeping_unfreeze(void); > > > > /* > > * Get and set timeofday > > diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c > > index c347e3c..6467fb8 100644 > > --- a/kernel/power/suspend.c > > +++ b/kernel/power/suspend.c > > @@ -28,6 +28,7 @@ > > #include <linux/ftrace.h> > > #include <trace/events/power.h> > > #include <linux/compiler.h> > > +#include <linux/clockchips.h> > > > > #include "power.h" > > > > @@ -37,7 +38,15 @@ const char *pm_states[PM_SUSPEND_MAX]; > > static const struct platform_suspend_ops *suspend_ops; > > static const struct platform_freeze_ops *freeze_ops; > > static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head); > > -static bool suspend_freeze_wake; > > + > > +/* freeze state machine */ > > +enum freeze_state { > > + FREEZE_STATE_NONE, /* not in freeze */ > > + FREEZE_STATE_ENTER, /* enter freeze */ > > + FREEZE_STATE_WAKE, /* in freeze wakeup context */ > > +}; > > + > > +static enum freeze_state suspend_freeze_state; > > > > void freeze_set_ops(const struct platform_freeze_ops *ops) > > { > > @@ -46,23 +55,56 @@ void freeze_set_ops(const struct platform_freeze_ops *ops) > > unlock_system_sleep(); > > } > > > > +bool in_freeze(void) > > +{ > > + return (suspend_freeze_state > FREEZE_STATE_NONE); > > +} > > +EXPORT_SYMBOL_GPL(in_freeze); > > + > > +bool idle_should_freeze(void) > > +{ > > + return (suspend_freeze_state == FREEZE_STATE_ENTER); > > +} > > +EXPORT_SYMBOL_GPL(idle_should_freeze); > > + > > static void freeze_begin(void) > > { > > - suspend_freeze_wake = false; > > + suspend_freeze_state = FREEZE_STATE_NONE; > > } > > > > static void freeze_enter(void) > > { > > + suspend_freeze_state = FREEZE_STATE_ENTER; > > + get_online_cpus(); > > cpuidle_use_deepest_state(true); > > cpuidle_resume(); > > - wait_event(suspend_freeze_wait_head, suspend_freeze_wake); > > + clockevents_notify(CLOCK_EVT_NOTIFY_FREEZE_PREPARE, NULL); > > + /* > > + * push all the CPUs into freeze idle loop > > + */ > > + wake_up_all_idle_cpus(); > > + printk(KERN_INFO "PM: suspend to idle\n"); > > + /* > > + * put the current CPU into wait queue so that this CPU > > + * is able to enter freeze idle loop as well > > + */ > > + wait_event(suspend_freeze_wait_head, > > + (suspend_freeze_state == FREEZE_STATE_WAKE)); > > + printk(KERN_INFO "PM: resume from freeze\n"); > > cpuidle_pause(); > > cpuidle_use_deepest_state(false); > > + put_online_cpus(); > > + suspend_freeze_state = FREEZE_STATE_NONE; > > } > > > > void freeze_wake(void) > > { > > - suspend_freeze_wake = true; > > + if (!in_freeze()) > > + return; > > + /* > > + * wake freeze task up > > + */ > > + suspend_freeze_state = FREEZE_STATE_WAKE; > > wake_up(&suspend_freeze_wait_head); > > } > > EXPORT_SYMBOL_GPL(freeze_wake); > > diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c > > index c47fce7..f28f8cb 100644 > > --- a/kernel/sched/idle.c > > +++ b/kernel/sched/idle.c > > @@ -7,6 +7,7 @@ > > #include <linux/tick.h> > > #include <linux/mm.h> > > #include <linux/stackprotector.h> > > +#include <linux/suspend.h> > > > > #include <asm/tlb.h> > > > > @@ -182,6 +183,45 @@ exit_idle: > > } > > > > /* > > + * cpu idle freeze function > > + */ > > +static void cpu_idle_freeze(void) > > +{ > > + struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices); > > + struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); > > + > > + /* > > + * suspend tick, the last CPU suspend timekeeping > > + */ > > + clockevents_notify(CLOCK_EVT_NOTIFY_FREEZE, NULL); > > + /* > > + * idle loop here if idle_should_freeze() > > + */ > > + while (idle_should_freeze()) { > > + int next_state; > > + /* > > + * interrupt must be disabled before cpu enters idle > > + */ > > + local_irq_disable(); > > + > > + next_state = cpuidle_select(drv, dev); > > + if (next_state < 0) { > > + arch_cpu_idle(); > > + continue; > > + } > > + /* > > + * cpuidle_enter will return with interrupt enabled > > + */ > > + cpuidle_enter(drv, dev, next_state); > > + } > > + > > + /* > > + * resume tick, the first wakeup CPU resume timekeeping > > + */ > > + clockevents_notify(CLOCK_EVT_NOTIFY_UNFREEZE, NULL); > > +} > > + > > +/* > > * Generic idle loop implementation > > * > > * Called with polling cleared. > > @@ -208,6 +248,11 @@ static void cpu_idle_loop(void) > > if (cpu_is_offline(smp_processor_id())) > > arch_cpu_idle_dead(); > > > > + if (idle_should_freeze()) { > > + cpu_idle_freeze(); > > + continue; > > + } > > + > > local_irq_disable(); > > arch_cpu_idle_enter(); > > > > diff --git a/kernel/softirq.c b/kernel/softirq.c > > index 0699add..a231bf6 100644 > > --- a/kernel/softirq.c > > +++ b/kernel/softirq.c > > @@ -26,6 +26,7 @@ > > #include <linux/smpboot.h> > > #include <linux/tick.h> > > #include <linux/irq.h> > > +#include <linux/suspend.h> > > > > #define CREATE_TRACE_POINTS > > #include <trace/events/irq.h> > > @@ -321,7 +322,7 @@ asmlinkage __visible void do_softirq(void) > > void irq_enter(void) > > { > > rcu_irq_enter(); > > - if (is_idle_task(current) && !in_interrupt()) { > > + if (is_idle_task(current) && !in_interrupt() && !in_freeze()) { > > /* > > * Prevent raise_softirq from needlessly waking up ksoftirqd > > * here, as softirq will be serviced on return from interrupt. > > @@ -364,7 +365,7 @@ static inline void tick_irq_exit(void) > > > > /* Make sure that timer wheel updates are propagated */ > > if ((idle_cpu(cpu) && !need_resched()) || tick_nohz_full_cpu(cpu)) { > > - if (!in_interrupt()) > > + if (!in_interrupt() && !in_freeze()) > > tick_nohz_irq_exit(); > > } > > #endif > > diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c > > index 5544990..6d9a4a3 100644 > > --- a/kernel/time/clockevents.c > > +++ b/kernel/time/clockevents.c > > @@ -17,6 +17,7 @@ > > #include <linux/module.h> > > #include <linux/smp.h> > > #include <linux/device.h> > > +#include <linux/suspend.h> > > > > #include "tick-internal.h" > > > > @@ -579,6 +580,18 @@ int clockevents_notify(unsigned long reason, void *arg) > > tick_resume(); > > break; > > > > + case CLOCK_EVT_NOTIFY_FREEZE_PREPARE: > > + tick_freeze_prepare(); > > + break; > > + > > + case CLOCK_EVT_NOTIFY_FREEZE: > > + tick_freeze(); > > + break; > > + > > + case CLOCK_EVT_NOTIFY_UNFREEZE: > > + tick_unfreeze(); > > + break; > > + > > case CLOCK_EVT_NOTIFY_CPU_DEAD: > > tick_shutdown_broadcast_oneshot(arg); > > tick_shutdown_broadcast(arg); > > diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c > > index 7efeedf..0bbc886 100644 > > --- a/kernel/time/tick-common.c > > +++ b/kernel/time/tick-common.c > > @@ -19,6 +19,7 @@ > > #include <linux/profile.h> > > #include <linux/sched.h> > > #include <linux/module.h> > > +#include <linux/suspend.h> > > > > #include <asm/irq_regs.h> > > > > @@ -51,6 +52,16 @@ ktime_t tick_period; > > int tick_do_timer_cpu __read_mostly = TICK_DO_TIMER_BOOT; > > > > /* > > + * Tick device is per CPU device, when we freeze the timekeeping stuff, we > > + * want to freeze the tick device on all of the online CPUs. > > + * > > + * tick_freeze_target_depth is a counter used for freezing tick device, the > > + * initial value of it is online CPU number. When it is counted down to ZERO, > > + * all of the tick devices are freezed. > > + */ > > +static unsigned int tick_freeze_target_depth; > > + > > +/* > > * Debugging: see timer_list.c > > */ > > struct tick_device *tick_get_device(int cpu) > > @@ -375,15 +386,21 @@ void tick_shutdown(unsigned int *cpup) > > void tick_suspend(void) > > { > > struct tick_device *td = this_cpu_ptr(&tick_cpu_device); > > + struct clock_event_device *dev = td->evtdev; > > > > + dev->real_handler = dev->event_handler; > > + dev->event_handler = clockevents_handle_noop; > > clockevents_shutdown(td->evtdev); > > } > > > > void tick_resume(void) > > { > > struct tick_device *td = this_cpu_ptr(&tick_cpu_device); > > + struct clock_event_device *dev = td->evtdev; > > int broadcast = tick_resume_broadcast(); > > > > + dev->event_handler = dev->real_handler; > > + dev->real_handler = NULL; > > clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_RESUME); > > > > if (!broadcast) { > > @@ -394,6 +411,42 @@ void tick_resume(void) > > } > > } > > > > +void tick_freeze_prepare(void) > > +{ > > + tick_freeze_target_depth = num_online_cpus(); > > +} > > + > > +void tick_freeze(void) > > +{ > > + /* > > + * This is serialized against a concurrent wakeup > > + * via clockevents_lock > > + */ > > + tick_freeze_target_depth--; > > + tick_suspend(); > > + > > + /* > > + * the last tick_suspend CPU suspends timekeeping > > + */ > > + if (!tick_freeze_target_depth) > > + timekeeping_freeze(); > > +} > > + > > +void tick_unfreeze(void) > > +{ > > + /* > > + * the first wakeup CPU resumes timekeeping > > + */ > > + if (timekeeping_suspended) { > > + timekeeping_unfreeze(); > > + touch_softlockup_watchdog(); > > + tick_resume(); > > + hrtimers_resume(); > > + } else { > > + tick_resume(); > > + } > > +} > > + > > /** > > * tick_init - initialize the tick control > > */ > > diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h > > index 366aeb4..8b5bab6 100644 > > --- a/kernel/time/tick-internal.h > > +++ b/kernel/time/tick-internal.h > > @@ -27,6 +27,9 @@ extern void tick_handover_do_timer(int *cpup); > > extern void tick_shutdown(unsigned int *cpup); > > extern void tick_suspend(void); > > extern void tick_resume(void); > > +extern void tick_freeze_prepare(void); > > +extern void tick_freeze(void); > > +extern void tick_unfreeze(void); > > extern bool tick_check_replacement(struct clock_event_device *curdev, > > struct clock_event_device *newdev); > > extern void tick_install_replacement(struct clock_event_device *dev); > > diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c > > index ec1791f..a11065f 100644 > > --- a/kernel/time/timekeeping.c > > +++ b/kernel/time/timekeeping.c > > @@ -1107,14 +1107,7 @@ void timekeeping_inject_sleeptime(struct timespec *delta) > > clock_was_set(); > > } > > > > -/** > > - * timekeeping_resume - Resumes the generic timekeeping subsystem. > > - * > > - * This is for the generic clocksource timekeeping. > > - * xtime/wall_to_monotonic/jiffies/etc are > > - * still managed by arch specific suspend/resume code. > > - */ > > -static void timekeeping_resume(void) > > +static void timekeeping_resume_compensate_time(void) > > { > > struct timekeeper *tk = &tk_core.timekeeper; > > struct clocksource *clock = tk->tkr.clock; > > @@ -1127,9 +1120,6 @@ static void timekeeping_resume(void) > > read_persistent_clock(&tmp); > > ts_new = timespec_to_timespec64(tmp); > > > > - clockevents_resume(); > > - clocksource_resume(); > > - > > raw_spin_lock_irqsave(&timekeeper_lock, flags); > > write_seqcount_begin(&tk_core.seq); > > > > @@ -1186,16 +1176,9 @@ static void timekeeping_resume(void) > > timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET); > > write_seqcount_end(&tk_core.seq); > > raw_spin_unlock_irqrestore(&timekeeper_lock, flags); > > - > > - touch_softlockup_watchdog(); > > - > > - clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); > > - > > - /* Resume hrtimers */ > > - hrtimers_resume(); > > } > > > > -static int timekeeping_suspend(void) > > +static void timekeeping_suspend_get_time(void) > > { > > struct timekeeper *tk = &tk_core.timekeeper; > > unsigned long flags; > > @@ -1242,11 +1225,65 @@ static int timekeeping_suspend(void) > > timekeeping_update(tk, TK_MIRROR); > > write_seqcount_end(&tk_core.seq); > > raw_spin_unlock_irqrestore(&timekeeper_lock, flags); > > +} > > > > - clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); > > +/* > > + * The following operations: > > + * clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); > > + * clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); > > + * are moved out of > > + * timekeeping_freeze() and timekeeping_unfreeze() > > + * and, replaced by > > + * tick_suspend() and tick_resume() > > + * and, put into: > > + * tick_freeze() and tick_unfreeze() > > + * so we avoid clockevents_lock multiple access > > + */ > > +void timekeeping_freeze(void) > > +{ > > + /* > > + * clockevents_lock being held > > + */ > > + timekeeping_suspend_get_time(); > > clocksource_suspend(); > > clockevents_suspend(); > > +} > > > > +void timekeeping_unfreeze(void) > > +{ > > + /* > > + * clockevents_lock being held > > + */ > > + clockevents_resume(); > > + clocksource_resume(); > > + timekeeping_resume_compensate_time(); > > +} > > + > > +/** > > + * timekeeping_resume - Resumes the generic timekeeping subsystem. > > + * > > + * This is for the generic clocksource timekeeping. > > + * xtime/wall_to_monotonic/jiffies/etc are > > + * still managed by arch specific suspend/resume code. > > + */ > > +static void timekeeping_resume(void) > > +{ > > + clockevents_resume(); > > + clocksource_resume(); > > + timekeeping_resume_compensate_time(); > > + > > + touch_softlockup_watchdog(); > > + clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); > > + /* Resume hrtimers */ > > + hrtimers_resume(); > > +} > > + > > +static int timekeeping_suspend(void) > > +{ > > + timekeeping_suspend_get_time(); > > + clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL); > > + clocksource_suspend(); > > + clockevents_suspend(); > > return 0; > > } > > > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
-- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.
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