From 5c333864a6ba811052d52ef14fbed056b9ac3512 Mon Sep 17 00:00:00 2001 From: Arun R Bharadwaj Date: Thu, 16 Apr 2009 12:14:37 +0530 Subject: timers: Identifying the existing pinned timers * Arun R Bharadwaj [2009-04-16 12:11:36]: The following pinned hrtimers have been identified and marked: 1)sched_rt_period_timer 2)tick_sched_timer 3)stack_trace_timer_fn [ tglx: fixup the hrtimer pinned mode ] Signed-off-by: Arun R Bharadwaj Signed-off-by: Thomas Gleixner --- kernel/time/tick-sched.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'kernel/time') diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index d3f1ef4d5cbe..2aff39c6f10c 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -349,7 +349,7 @@ void tick_nohz_stop_sched_tick(int inidle) if (ts->nohz_mode == NOHZ_MODE_HIGHRES) { hrtimer_start(&ts->sched_timer, expires, - HRTIMER_MODE_ABS); + HRTIMER_MODE_ABS_PINNED); /* Check, if the timer was already in the past */ if (hrtimer_active(&ts->sched_timer)) goto out; @@ -395,7 +395,7 @@ static void tick_nohz_restart(struct tick_sched *ts, ktime_t now) if (ts->nohz_mode == NOHZ_MODE_HIGHRES) { hrtimer_start_expires(&ts->sched_timer, - HRTIMER_MODE_ABS); + HRTIMER_MODE_ABS_PINNED); /* Check, if the timer was already in the past */ if (hrtimer_active(&ts->sched_timer)) break; @@ -698,7 +698,8 @@ void tick_setup_sched_timer(void) for (;;) { hrtimer_forward(&ts->sched_timer, now, tick_period); - hrtimer_start_expires(&ts->sched_timer, HRTIMER_MODE_ABS); + hrtimer_start_expires(&ts->sched_timer, + HRTIMER_MODE_ABS_PINNED); /* Check, if the timer was already in the past */ if (hrtimer_active(&ts->sched_timer)) break; -- cgit v1.2.2 From eea08f32adb3f97553d49a4f79a119833036000a Mon Sep 17 00:00:00 2001 From: Arun R Bharadwaj Date: Thu, 16 Apr 2009 12:16:41 +0530 Subject: timers: Logic to move non pinned timers * Arun R Bharadwaj [2009-04-16 12:11:36]: This patch migrates all non pinned timers and hrtimers to the current idle load balancer, from all the idle CPUs. Timers firing on busy CPUs are not migrated. While migrating hrtimers, care should be taken to check if migrating a hrtimer would result in a latency or not. So we compare the expiry of the hrtimer with the next timer interrupt on the target cpu and migrate the hrtimer only if it expires *after* the next interrupt on the target cpu. So, added a clockevents_get_next_event() helper function to return the next_event on the target cpu's clock_event_device. [ tglx: cleanups and simplifications ] Signed-off-by: Arun R Bharadwaj Signed-off-by: Thomas Gleixner --- kernel/time/clockevents.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'kernel/time') diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index d13be216a790..ab20ded013bd 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -18,6 +18,7 @@ #include #include #include +#include /* The registered clock event devices */ static LIST_HEAD(clockevent_devices); @@ -251,4 +252,15 @@ void clockevents_notify(unsigned long reason, void *arg) spin_unlock(&clockevents_lock); } EXPORT_SYMBOL_GPL(clockevents_notify); + +ktime_t clockevents_get_next_event(int cpu) +{ + struct tick_device *td; + struct clock_event_device *dev; + + td = &per_cpu(tick_cpu_device, cpu); + dev = td->evtdev; + + return dev->next_event; +} #endif -- cgit v1.2.2