From b12a03ce4880bd13786a98db6de494a3e0123129 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 2 May 2011 16:48:57 +0200 Subject: hrtimers: Prepare for cancel on clock was set timers Make clock_was_set() unconditional and rename hres_timers_resume to hrtimers_resume. This is a preparatory patch for hrtimers which are cancelled when clock realtime was set. Signed-off-by: Thomas Gleixner --- kernel/hrtimer.c | 125 ++++++++++++++++++++++------------------------ kernel/time/timekeeping.c | 2 +- 2 files changed, 62 insertions(+), 65 deletions(-) (limited to 'kernel') diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index dbbbf7d43080..c145ed643bca 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -621,66 +621,6 @@ static int hrtimer_reprogram(struct hrtimer *timer, return res; } - -/* - * Retrigger next event is called after clock was set - * - * Called with interrupts disabled via on_each_cpu() - */ -static void retrigger_next_event(void *arg) -{ - struct hrtimer_cpu_base *base; - struct timespec realtime_offset, wtm, sleep; - - if (!hrtimer_hres_active()) - return; - - get_xtime_and_monotonic_and_sleep_offset(&realtime_offset, &wtm, - &sleep); - set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec); - - base = &__get_cpu_var(hrtimer_bases); - - /* Adjust CLOCK_REALTIME offset */ - raw_spin_lock(&base->lock); - base->clock_base[HRTIMER_BASE_REALTIME].offset = - timespec_to_ktime(realtime_offset); - base->clock_base[HRTIMER_BASE_BOOTTIME].offset = - timespec_to_ktime(sleep); - - hrtimer_force_reprogram(base, 0); - raw_spin_unlock(&base->lock); -} - -/* - * Clock realtime was set - * - * Change the offset of the realtime clock vs. the monotonic - * clock. - * - * We might have to reprogram the high resolution timer interrupt. On - * SMP we call the architecture specific code to retrigger _all_ high - * resolution timer interrupts. On UP we just disable interrupts and - * call the high resolution interrupt code. - */ -void clock_was_set(void) -{ - /* Retrigger the CPU local events everywhere */ - on_each_cpu(retrigger_next_event, NULL, 1); -} - -/* - * During resume we might have to reprogram the high resolution timer - * interrupt (on the local CPU): - */ -void hres_timers_resume(void) -{ - WARN_ONCE(!irqs_disabled(), - KERN_INFO "hres_timers_resume() called with IRQs enabled!"); - - retrigger_next_event(NULL); -} - /* * Initialize the high resolution related parts of cpu_base */ @@ -714,12 +654,14 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer, return 0; } +static void retrigger_next_event(void *arg); + /* * Switch to high resolution mode */ static int hrtimer_switch_to_hres(void) { - int cpu = smp_processor_id(); + int i, cpu = smp_processor_id(); struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu); unsigned long flags; @@ -735,9 +677,8 @@ static int hrtimer_switch_to_hres(void) return 0; } base->hres_active = 1; - base->clock_base[HRTIMER_BASE_REALTIME].resolution = KTIME_HIGH_RES; - base->clock_base[HRTIMER_BASE_MONOTONIC].resolution = KTIME_HIGH_RES; - base->clock_base[HRTIMER_BASE_BOOTTIME].resolution = KTIME_HIGH_RES; + for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) + base->clock_base[i].resolution = KTIME_HIGH_RES; tick_setup_sched_timer(); @@ -764,6 +705,62 @@ static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { } #endif /* CONFIG_HIGH_RES_TIMERS */ +/* + * Retrigger next event is called after clock was set + * + * Called with interrupts disabled via on_each_cpu() + */ +static void retrigger_next_event(void *arg) +{ + struct hrtimer_cpu_base *base = &__get_cpu_var(hrtimer_bases); + struct timespec realtime_offset, xtim, wtm, sleep; + + if (!hrtimer_hres_active()) + return; + + get_xtime_and_monotonic_and_sleep_offset(&xtim, &wtm, &sleep); + set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec); + + /* Adjust CLOCK_REALTIME offset */ + raw_spin_lock(&base->lock); + base->clock_base[HRTIMER_BASE_REALTIME].offset = + timespec_to_ktime(realtime_offset); + base->clock_base[HRTIMER_BASE_BOOTTIME].offset = + timespec_to_ktime(sleep); + + hrtimer_force_reprogram(base, 0); + raw_spin_unlock(&base->lock); +} + +/* + * Clock realtime was set + * + * Change the offset of the realtime clock vs. the monotonic + * clock. + * + * We might have to reprogram the high resolution timer interrupt. On + * SMP we call the architecture specific code to retrigger _all_ high + * resolution timer interrupts. On UP we just disable interrupts and + * call the high resolution interrupt code. + */ +void clock_was_set(void) +{ + /* Retrigger the CPU local events everywhere */ + on_each_cpu(retrigger_next_event, NULL, 1); +} + +/* + * During resume we might have to reprogram the high resolution timer + * interrupt (on the local CPU): + */ +void hrtimers_resume(void) +{ + WARN_ONCE(!irqs_disabled(), + KERN_INFO "hrtimers_resume() called with IRQs enabled!"); + + retrigger_next_event(NULL); +} + static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer) { #ifdef CONFIG_TIMER_STATS diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 8e6a05a5915a..a61b8fa2d39a 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -680,7 +680,7 @@ static void timekeeping_resume(void) clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL); /* Resume hrtimers */ - hres_timers_resume(); + hrtimers_resume(); } static int timekeeping_suspend(void) -- cgit v1.2.3 From 99ee5315dac6211e972fa3f23bcc9a0343ff58c4 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 27 Apr 2011 14:16:42 +0200 Subject: timerfd: Allow timers to be cancelled when clock was set Some applications must be aware of clock realtime being set backward. A simple example is a clock applet which arms a timer for the next minute display. If clock realtime is set backward then the applet displays a stale time for the amount of time which the clock was set backwards. Due to that applications poll the time because we don't have an interface. Extend the timerfd interface by adding a flag which puts the timer onto a different internal realtime clock. All timers on this clock are expired whenever the clock was set. The timerfd core records the monotonic offset when the timer is created. When the timer is armed, then the current offset is compared to the previous recorded offset. When it has changed, then timerfd_settime returns -ECANCELED. When a timer is read the offset is compared and if it changed -ECANCELED returned to user space. Periodic timers are not rearmed in the cancelation case. Signed-off-by: Thomas Gleixner Acked-by: John Stultz Cc: Chris Friesen Tested-by: Kay Sievers Cc: "Kirill A. Shutemov" Cc: Peter Zijlstra Cc: Davide Libenzi Reviewed-by: Alexander Shishkin Link: http://lkml.kernel.org/r/%3Calpine.LFD.2.02.1104271359580.3323%40ionos%3E Signed-off-by: Thomas Gleixner --- kernel/hrtimer.c | 36 +++++++++++++++++++++++++++++++++++- kernel/time/timekeeping.c | 15 +++++++++++++++ 2 files changed, 50 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index c145ed643bca..eabcbd781433 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -78,6 +78,11 @@ DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) = .get_time = &ktime_get_boottime, .resolution = KTIME_LOW_RES, }, + { + .index = CLOCK_REALTIME_COS, + .get_time = &ktime_get_real, + .resolution = KTIME_LOW_RES, + }, } }; @@ -85,6 +90,7 @@ static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = { [CLOCK_REALTIME] = HRTIMER_BASE_REALTIME, [CLOCK_MONOTONIC] = HRTIMER_BASE_MONOTONIC, [CLOCK_BOOTTIME] = HRTIMER_BASE_BOOTTIME, + [CLOCK_REALTIME_COS] = HRTIMER_BASE_REALTIME_COS, }; static inline int hrtimer_clockid_to_base(clockid_t clock_id) @@ -110,6 +116,7 @@ static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base) base->clock_base[HRTIMER_BASE_REALTIME].softirq_time = xtim; base->clock_base[HRTIMER_BASE_MONOTONIC].softirq_time = mono; base->clock_base[HRTIMER_BASE_BOOTTIME].softirq_time = boot; + base->clock_base[HRTIMER_BASE_REALTIME_COS].softirq_time = xtim; } /* @@ -479,6 +486,8 @@ static inline void debug_deactivate(struct hrtimer *timer) trace_hrtimer_cancel(timer); } +static void hrtimer_expire_cancelable(struct hrtimer_cpu_base *cpu_base); + /* High resolution timer related functions */ #ifdef CONFIG_HIGH_RES_TIMERS @@ -715,9 +724,14 @@ static void retrigger_next_event(void *arg) struct hrtimer_cpu_base *base = &__get_cpu_var(hrtimer_bases); struct timespec realtime_offset, xtim, wtm, sleep; - if (!hrtimer_hres_active()) + if (!hrtimer_hres_active()) { + raw_spin_lock(&base->lock); + hrtimer_expire_cancelable(base); + raw_spin_unlock(&base->lock); return; + } + /* Optimized out for !HIGH_RES */ get_xtime_and_monotonic_and_sleep_offset(&xtim, &wtm, &sleep); set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec); @@ -727,6 +741,10 @@ static void retrigger_next_event(void *arg) timespec_to_ktime(realtime_offset); base->clock_base[HRTIMER_BASE_BOOTTIME].offset = timespec_to_ktime(sleep); + base->clock_base[HRTIMER_BASE_REALTIME_COS].offset = + timespec_to_ktime(realtime_offset); + + hrtimer_expire_cancelable(base); hrtimer_force_reprogram(base, 0); raw_spin_unlock(&base->lock); @@ -1222,6 +1240,22 @@ static void __run_hrtimer(struct hrtimer *timer, ktime_t *now) timer->state &= ~HRTIMER_STATE_CALLBACK; } +static void hrtimer_expire_cancelable(struct hrtimer_cpu_base *cpu_base) +{ + struct timerqueue_node *node; + struct hrtimer_clock_base *base; + ktime_t now = ktime_get_real(); + + base = &cpu_base->clock_base[HRTIMER_BASE_REALTIME_COS]; + + while ((node = timerqueue_getnext(&base->active))) { + struct hrtimer *timer; + + timer = container_of(node, struct hrtimer, node); + __run_hrtimer(timer, &now); + } +} + #ifdef CONFIG_HIGH_RES_TIMERS /* diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index a61b8fa2d39a..342408cf68dd 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1098,6 +1098,21 @@ void get_xtime_and_monotonic_and_sleep_offset(struct timespec *xtim, } while (read_seqretry(&xtime_lock, seq)); } +/** + * ktime_get_monotonic_offset() - get wall_to_monotonic in ktime_t format + */ +ktime_t ktime_get_monotonic_offset(void) +{ + unsigned long seq; + struct timespec wtom; + + do { + seq = read_seqbegin(&xtime_lock); + wtom = wall_to_monotonic; + } while (read_seqretry(&xtime_lock, seq)); + return timespec_to_ktime(wtom); +} + /** * xtime_update() - advances the timekeeping infrastructure * @ticks: number of ticks, that have elapsed since the last call. -- cgit v1.2.3 From ce788f930b0cdf821de7ee8f84cfe8cf7fcb6311 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 4 May 2011 08:00:47 +0200 Subject: alarmtimer: Check return value of class_find_device() alarmtimer_late_init() uses class_find_device() to find a alarm capable rtc device. The match callback stores a pointer to the name in the char pointer handed in from the call site. alarmtimer_late_init() checks the char pointer for NULL, but the pointer is on the stack and not initialized to NULL before the call. So it can have random content when the match function did not identify a device, which leads to random access in the following rtc_open() call where the pointer is dereferenced Instead of relying on the char pointer, check the return value of class_find_device. If a device is found then the name pointer is valid as well. Reported-by: Ingo Molnar Cc: John Stultz Signed-off-by: Thomas Gleixner --- kernel/time/alarmtimer.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index 9265014cb4db..e5db9b00751b 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -669,11 +669,13 @@ static int __init has_wakealarm(struct device *dev, void *name_ptr) */ static int __init alarmtimer_init_late(void) { + struct device *dev; char *str; /* Find an rtc device and init the rtc_timer */ - class_find_device(rtc_class, NULL, &str, has_wakealarm); - if (str) + dev = class_find_device(rtc_class, NULL, &str, has_wakealarm); + /* If we have a device then str is valid. See has_wakealarm() */ + if (dev) rtcdev = rtc_class_open(str); if (!rtcdev) { printk(KERN_WARNING "No RTC device found, ALARM timers will" -- cgit v1.2.3 From 179eb03268aa1da03d90f1566ea85dc1478d3ae3 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 4 May 2011 08:18:34 +0200 Subject: alarmtimer: Drop device refcount after rtc_open() class_find_device() takes a refcount on the rtc device. rtc_open() takes another one, so we can drop it after the rtc_open() call. Signed-off-by: Thomas Gleixner Cc: John Stultz --- kernel/time/alarmtimer.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index e5db9b00751b..c6027fe9a4e6 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -675,8 +675,14 @@ static int __init alarmtimer_init_late(void) /* Find an rtc device and init the rtc_timer */ dev = class_find_device(rtc_class, NULL, &str, has_wakealarm); /* If we have a device then str is valid. See has_wakealarm() */ - if (dev) + if (dev) { rtcdev = rtc_class_open(str); + /* + * Drop the reference we got in class_find_device, + * rtc_open takes its own. + */ + put_device(dev); + } if (!rtcdev) { printk(KERN_WARNING "No RTC device found, ALARM timers will" " not wake from suspend"); -- cgit v1.2.3 From 7372b0b122af0f6675f3ab65bfd91c8a438e0480 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Wed, 4 May 2011 15:09:27 -0700 Subject: clockevents: Move C3 stop test outside lock Avoid taking broadcast_lock in the idle path for systems where the timer doesn't stop in C3. [ tglx: Removed the stale label and added comment ] Signed-off-by: Andi Kleen Cc: Dave Kleikamp Cc: Chris Mason Cc: Peter Zijlstra Cc: Tim Chen Cc: lenb@kernel.org Cc: paulmck@us.ibm.com Link: http://lkml.kernel.org/r/%3C20110504234806.GF2925%40one.firstfloor.org%3E Signed-off-by: Thomas Gleixner --- kernel/time/tick-broadcast.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index da800ffa810c..827e0f862da4 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -456,23 +456,27 @@ void tick_broadcast_oneshot_control(unsigned long reason) unsigned long flags; int cpu; - raw_spin_lock_irqsave(&tick_broadcast_lock, flags); - /* * Periodic mode does not care about the enter/exit of power * states */ if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) - goto out; + return; - bc = tick_broadcast_device.evtdev; + /* + * We are called with preemtion disabled from the depth of the + * idle code, so we can't be moved away. + */ cpu = smp_processor_id(); td = &per_cpu(tick_cpu_device, cpu); dev = td->evtdev; if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) - goto out; + return; + + bc = tick_broadcast_device.evtdev; + raw_spin_lock_irqsave(&tick_broadcast_lock, flags); if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) { if (!cpumask_test_cpu(cpu, tick_get_broadcast_oneshot_mask())) { cpumask_set_cpu(cpu, tick_get_broadcast_oneshot_mask()); @@ -489,8 +493,6 @@ void tick_broadcast_oneshot_control(unsigned long reason) tick_program_event(dev->next_event, 1); } } - -out: raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); } -- cgit v1.2.3 From 9ec2690758a5467f24beb301cca5098078073bba Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 20 May 2011 16:18:50 +0200 Subject: timerfd: Manage cancelable timers in timerfd Peter is concerned about the extra scan of CLOCK_REALTIME_COS in the timer interrupt. Yes, I did not think about it, because the solution was so elegant. I didn't like the extra list in timerfd when it was proposed some time ago, but with a rcu based list the list walk it's less horrible than the original global lock, which was held over the list iteration. Requested-by: Peter Zijlstra Signed-off-by: Thomas Gleixner Reviewed-by: Peter Zijlstra --- kernel/hrtimer.c | 94 +++++++++++++++++++------------------------------------- 1 file changed, 32 insertions(+), 62 deletions(-) (limited to 'kernel') diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index eabcbd781433..26dd32f9f6b2 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -78,11 +78,6 @@ DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) = .get_time = &ktime_get_boottime, .resolution = KTIME_LOW_RES, }, - { - .index = CLOCK_REALTIME_COS, - .get_time = &ktime_get_real, - .resolution = KTIME_LOW_RES, - }, } }; @@ -90,7 +85,6 @@ static const int hrtimer_clock_to_base_table[MAX_CLOCKS] = { [CLOCK_REALTIME] = HRTIMER_BASE_REALTIME, [CLOCK_MONOTONIC] = HRTIMER_BASE_MONOTONIC, [CLOCK_BOOTTIME] = HRTIMER_BASE_BOOTTIME, - [CLOCK_REALTIME_COS] = HRTIMER_BASE_REALTIME_COS, }; static inline int hrtimer_clockid_to_base(clockid_t clock_id) @@ -116,7 +110,6 @@ static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base) base->clock_base[HRTIMER_BASE_REALTIME].softirq_time = xtim; base->clock_base[HRTIMER_BASE_MONOTONIC].softirq_time = mono; base->clock_base[HRTIMER_BASE_BOOTTIME].softirq_time = boot; - base->clock_base[HRTIMER_BASE_REALTIME_COS].softirq_time = xtim; } /* @@ -486,8 +479,6 @@ static inline void debug_deactivate(struct hrtimer *timer) trace_hrtimer_cancel(timer); } -static void hrtimer_expire_cancelable(struct hrtimer_cpu_base *cpu_base); - /* High resolution timer related functions */ #ifdef CONFIG_HIGH_RES_TIMERS @@ -663,7 +654,33 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer, return 0; } -static void retrigger_next_event(void *arg); +/* + * Retrigger next event is called after clock was set + * + * Called with interrupts disabled via on_each_cpu() + */ +static void retrigger_next_event(void *arg) +{ + struct hrtimer_cpu_base *base = &__get_cpu_var(hrtimer_bases); + struct timespec realtime_offset, xtim, wtm, sleep; + + if (!hrtimer_hres_active()) + return; + + /* Optimized out for !HIGH_RES */ + get_xtime_and_monotonic_and_sleep_offset(&xtim, &wtm, &sleep); + set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec); + + /* Adjust CLOCK_REALTIME offset */ + raw_spin_lock(&base->lock); + base->clock_base[HRTIMER_BASE_REALTIME].offset = + timespec_to_ktime(realtime_offset); + base->clock_base[HRTIMER_BASE_BOOTTIME].offset = + timespec_to_ktime(sleep); + + hrtimer_force_reprogram(base, 0); + raw_spin_unlock(&base->lock); +} /* * Switch to high resolution mode @@ -711,45 +728,10 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer, return 0; } static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { } +static inline void retrigger_next_event(void *arg) { } #endif /* CONFIG_HIGH_RES_TIMERS */ -/* - * Retrigger next event is called after clock was set - * - * Called with interrupts disabled via on_each_cpu() - */ -static void retrigger_next_event(void *arg) -{ - struct hrtimer_cpu_base *base = &__get_cpu_var(hrtimer_bases); - struct timespec realtime_offset, xtim, wtm, sleep; - - if (!hrtimer_hres_active()) { - raw_spin_lock(&base->lock); - hrtimer_expire_cancelable(base); - raw_spin_unlock(&base->lock); - return; - } - - /* Optimized out for !HIGH_RES */ - get_xtime_and_monotonic_and_sleep_offset(&xtim, &wtm, &sleep); - set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec); - - /* Adjust CLOCK_REALTIME offset */ - raw_spin_lock(&base->lock); - base->clock_base[HRTIMER_BASE_REALTIME].offset = - timespec_to_ktime(realtime_offset); - base->clock_base[HRTIMER_BASE_BOOTTIME].offset = - timespec_to_ktime(sleep); - base->clock_base[HRTIMER_BASE_REALTIME_COS].offset = - timespec_to_ktime(realtime_offset); - - hrtimer_expire_cancelable(base); - - hrtimer_force_reprogram(base, 0); - raw_spin_unlock(&base->lock); -} - /* * Clock realtime was set * @@ -763,8 +745,11 @@ static void retrigger_next_event(void *arg) */ void clock_was_set(void) { +#ifdef CONFIG_HIGHRES_TIMERS /* Retrigger the CPU local events everywhere */ on_each_cpu(retrigger_next_event, NULL, 1); +#endif + timerfd_clock_was_set(); } /* @@ -777,6 +762,7 @@ void hrtimers_resume(void) KERN_INFO "hrtimers_resume() called with IRQs enabled!"); retrigger_next_event(NULL); + timerfd_clock_was_set(); } static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer) @@ -1240,22 +1226,6 @@ static void __run_hrtimer(struct hrtimer *timer, ktime_t *now) timer->state &= ~HRTIMER_STATE_CALLBACK; } -static void hrtimer_expire_cancelable(struct hrtimer_cpu_base *cpu_base) -{ - struct timerqueue_node *node; - struct hrtimer_clock_base *base; - ktime_t now = ktime_get_real(); - - base = &cpu_base->clock_base[HRTIMER_BASE_REALTIME_COS]; - - while ((node = timerqueue_getnext(&base->active))) { - struct hrtimer *timer; - - timer = container_of(node, struct hrtimer, node); - __run_hrtimer(timer, &now); - } -} - #ifdef CONFIG_HIGH_RES_TIMERS /* -- cgit v1.2.3 From ab8177bc53e8ae3a3ba6d200ce2c2dae263f7ee5 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 20 May 2011 13:05:15 +0200 Subject: hrtimers: Avoid touching inactive timer bases Instead of iterating over all possible timer bases avoid it by marking the active bases in the cpu base. Signed-off-by: Thomas Gleixner Reviewed-by: Peter Zijlstra --- kernel/hrtimer.c | 29 ++++++++++++++++++----------- kernel/posix-cpu-timers.c | 4 ++-- kernel/posix-timers.c | 2 +- kernel/time/alarmtimer.c | 4 ++-- 4 files changed, 23 insertions(+), 16 deletions(-) (limited to 'kernel') diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index 26dd32f9f6b2..1b08f6d67f12 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -64,17 +64,20 @@ DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) = .clock_base = { { - .index = CLOCK_REALTIME, + .index = HRTIMER_BASE_REALTIME, + .clockid = CLOCK_REALTIME, .get_time = &ktime_get_real, .resolution = KTIME_LOW_RES, }, { - .index = CLOCK_MONOTONIC, + .index = HRTIMER_BASE_MONOTONIC, + .clockid = CLOCK_MONOTONIC, .get_time = &ktime_get, .resolution = KTIME_LOW_RES, }, { - .index = CLOCK_BOOTTIME, + .index = HRTIMER_BASE_BOOTTIME, + .clockid = CLOCK_BOOTTIME, .get_time = &ktime_get_boottime, .resolution = KTIME_LOW_RES, }, @@ -196,7 +199,7 @@ switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base, struct hrtimer_cpu_base *new_cpu_base; int this_cpu = smp_processor_id(); int cpu = hrtimer_get_target(this_cpu, pinned); - int basenum = hrtimer_clockid_to_base(base->index); + int basenum = base->index; again: new_cpu_base = &per_cpu(hrtimer_bases, cpu); @@ -857,6 +860,7 @@ static int enqueue_hrtimer(struct hrtimer *timer, debug_activate(timer); timerqueue_add(&base->active, &timer->node); + base->cpu_base->active_bases |= 1 << base->index; /* * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the @@ -898,6 +902,8 @@ static void __remove_hrtimer(struct hrtimer *timer, #endif } timerqueue_del(&base->active, &timer->node); + if (!timerqueue_getnext(&base->active)) + base->cpu_base->active_bases &= ~(1 << base->index); out: timer->state = newstate; } @@ -1235,7 +1241,6 @@ static void __run_hrtimer(struct hrtimer *timer, ktime_t *now) void hrtimer_interrupt(struct clock_event_device *dev) { struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); - struct hrtimer_clock_base *base; ktime_t expires_next, now, entry_time, delta; int i, retries = 0; @@ -1257,12 +1262,15 @@ retry: */ cpu_base->expires_next.tv64 = KTIME_MAX; - base = cpu_base->clock_base; - for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) { - ktime_t basenow; + struct hrtimer_clock_base *base; struct timerqueue_node *node; + ktime_t basenow; + + if (!(cpu_base->active_bases & (1 << i))) + continue; + base = cpu_base->clock_base + i; basenow = ktime_add(now, base->offset); while ((node = timerqueue_getnext(&base->active))) { @@ -1295,7 +1303,6 @@ retry: __run_hrtimer(timer, &basenow); } - base++; } /* @@ -1526,7 +1533,7 @@ long __sched hrtimer_nanosleep_restart(struct restart_block *restart) struct timespec __user *rmtp; int ret = 0; - hrtimer_init_on_stack(&t.timer, restart->nanosleep.index, + hrtimer_init_on_stack(&t.timer, restart->nanosleep.clockid, HRTIMER_MODE_ABS); hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires); @@ -1578,7 +1585,7 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp, restart = ¤t_thread_info()->restart_block; restart->fn = hrtimer_nanosleep_restart; - restart->nanosleep.index = t.timer.base->index; + restart->nanosleep.clockid = t.timer.base->clockid; restart->nanosleep.rmtp = rmtp; restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer); diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c index 0791b13df7bf..58f405b581e7 100644 --- a/kernel/posix-cpu-timers.c +++ b/kernel/posix-cpu-timers.c @@ -1514,7 +1514,7 @@ static int posix_cpu_nsleep(const clockid_t which_clock, int flags, return -EFAULT; restart_block->fn = posix_cpu_nsleep_restart; - restart_block->nanosleep.index = which_clock; + restart_block->nanosleep.clockid = which_clock; restart_block->nanosleep.rmtp = rmtp; restart_block->nanosleep.expires = timespec_to_ns(rqtp); } @@ -1523,7 +1523,7 @@ static int posix_cpu_nsleep(const clockid_t which_clock, int flags, static long posix_cpu_nsleep_restart(struct restart_block *restart_block) { - clockid_t which_clock = restart_block->nanosleep.index; + clockid_t which_clock = restart_block->nanosleep.clockid; struct timespec t; struct itimerspec it; int error; diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c index e5498d7405c3..a1b5edf1bf92 100644 --- a/kernel/posix-timers.c +++ b/kernel/posix-timers.c @@ -1056,7 +1056,7 @@ SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags, */ long clock_nanosleep_restart(struct restart_block *restart_block) { - clockid_t which_clock = restart_block->nanosleep.index; + clockid_t which_clock = restart_block->nanosleep.clockid; struct k_clock *kc = clockid_to_kclock(which_clock); if (WARN_ON_ONCE(!kc || !kc->nsleep_restart)) diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index c6027fe9a4e6..2d966244ea60 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -494,7 +494,7 @@ static int update_rmtp(ktime_t exp, enum alarmtimer_type type, */ static long __sched alarm_timer_nsleep_restart(struct restart_block *restart) { - enum alarmtimer_type type = restart->nanosleep.index; + enum alarmtimer_type type = restart->nanosleep.clockid; ktime_t exp; struct timespec __user *rmtp; struct alarm alarm; @@ -573,7 +573,7 @@ static int alarm_timer_nsleep(const clockid_t which_clock, int flags, restart = ¤t_thread_info()->restart_block; restart->fn = alarm_timer_nsleep_restart; - restart->nanosleep.index = type; + restart->nanosleep.clockid = type; restart->nanosleep.expires = exp.tv64; restart->nanosleep.rmtp = rmtp; ret = -ERESTART_RESTARTBLOCK; -- cgit v1.2.3 From 68fa61c026057a39d6ccb850aa8785043afbee02 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 20 May 2011 23:14:04 +0200 Subject: hrtimers: Reorder clock bases The ordering of the clock bases is historical due to the CLOCK_REALTIME and CLOCK_MONOTONIC constants. Now the hrtimer bases have their own enumeration due to the gap between CLOCK_MONOTONIC and CLOCK_BOOTTIME. So we can be more clever as most timers end up on the CLOCK_MONOTONIC base due to the virtue of POSIX declaring that relative CLOCK_REALTIME timers are not affected by time changes. In desktop environments this is slowly changing as applications switch to absolute timers, but I've observed empty CLOCK_REALTIME bases often enough. There is no performance penalty or overhead when CLOCK_REALTIME timers are active, but in case they are not we don't skip over a full cache line. Signed-off-by: Thomas Gleixner Reviewed-by: Peter Zijlstra --- kernel/hrtimer.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index 1b08f6d67f12..c541ee527ecb 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -63,18 +63,18 @@ DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) = .clock_base = { - { - .index = HRTIMER_BASE_REALTIME, - .clockid = CLOCK_REALTIME, - .get_time = &ktime_get_real, - .resolution = KTIME_LOW_RES, - }, { .index = HRTIMER_BASE_MONOTONIC, .clockid = CLOCK_MONOTONIC, .get_time = &ktime_get, .resolution = KTIME_LOW_RES, }, + { + .index = HRTIMER_BASE_REALTIME, + .clockid = CLOCK_REALTIME, + .get_time = &ktime_get_real, + .resolution = KTIME_LOW_RES, + }, { .index = HRTIMER_BASE_BOOTTIME, .clockid = CLOCK_BOOTTIME, -- cgit v1.2.3