From e2e45baa03ae8a7e5e86ab3703983ca18670f869 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Wed, 25 Mar 2015 11:57:45 +0530 Subject: [PATCH] hrtimer: update timer->state with 'pinned' information 'Pinned' information would be required in migrate_hrtimers() now, as we can migrate non-pinned timers away without a hotplug (i.e. with cpuset.quiesce). And so we may need to identify pinned timers now, as we can't migrate them. This patch reuses the timer->state variable for setting this flag as there were enough number of free bits available in this variable. And there is no point increasing size of this struct by adding another field. Change-Id: Id2cdd74903598e31fab6999c4cbab9c2fd17fe23 Signed-off-by: Viresh Kumar [forward port to 3.18] Signed-off-by: Santosh Shukla [ohaugan@codeaurora.org: Port to 4.4] Git-commit: 62feaf1ed0b64c04868d143d8bdb92d60dc3189b Git-repo: git://git.linaro.org/people/mike.holmes/santosh.shukla/lng-isol.git Signed-off-by: Olav Haugan [markivx: Port to 4.14, fix merge conflicts due to lack of timer stats code] Signed-off-by: Vikram Mulukutla [satyap@codeaurora.org: Port to 4.19, fix merge conflicts] Signed-off-by: Satya Durga Srinivasu Prabhala --- include/linux/hrtimer.h | 3 +++ kernel/time/hrtimer.c | 19 ++++++++++++++----- 2 files changed, 17 insertions(+), 5 deletions(-) diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 1b9a51a1bccb..58da31bac5c5 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -73,6 +73,7 @@ enum hrtimer_restart { * * 0x00 inactive * 0x01 enqueued into rbtree + * 0x02 timer is pinned to a cpu * * The callback state is not part of the timer->state because clearing it would * mean touching the timer after the callback, this makes it impossible to free @@ -92,6 +93,8 @@ enum hrtimer_restart { */ #define HRTIMER_STATE_INACTIVE 0x00 #define HRTIMER_STATE_ENQUEUED 0x01 +#define HRTIMER_PINNED_SHIFT 1 +#define HRTIMER_STATE_PINNED (1 << HRTIMER_PINNED_SHIFT) /** * struct hrtimer - the basic hrtimer structure diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 65605530ee34..af9c2d855008 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -966,7 +966,7 @@ static int enqueue_hrtimer(struct hrtimer *timer, base->cpu_base->active_bases |= 1 << base->index; - timer->state = HRTIMER_STATE_ENQUEUED; + timer->state |= HRTIMER_STATE_ENQUEUED; return timerqueue_add(&base->active, &timer->node); } @@ -986,11 +986,9 @@ static void __remove_hrtimer(struct hrtimer *timer, u8 newstate, int reprogram) { struct hrtimer_cpu_base *cpu_base = base->cpu_base; - u8 state = timer->state; - timer->state = newstate; - if (!(state & HRTIMER_STATE_ENQUEUED)) - return; + if (!(timer->state & HRTIMER_STATE_ENQUEUED)) + goto out; if (!timerqueue_del(&base->active, &timer->node)) cpu_base->active_bases &= ~(1 << base->index); @@ -1005,6 +1003,13 @@ static void __remove_hrtimer(struct hrtimer *timer, */ if (reprogram && timer == cpu_base->next_timer) hrtimer_force_reprogram(cpu_base, 1); + +out: + /* + * We need to preserve PINNED state here, otherwise we may end up + * migrating pinned hrtimers as well. + */ + timer->state = newstate | (timer->state & HRTIMER_STATE_PINNED); } /* @@ -1097,6 +1102,10 @@ static int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, /* Switch the timer base, if necessary: */ new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED); + /* Update pinned state */ + timer->state &= ~HRTIMER_STATE_PINNED; + timer->state |= !!(mode & HRTIMER_MODE_PINNED) << HRTIMER_PINNED_SHIFT; + return enqueue_hrtimer(timer, new_base, mode); }