diff options
| -rw-r--r-- | include/linux/posix-timers.h | 7 | ||||
| -rw-r--r-- | kernel/time/posix-cpu-timers.c | 41 |
2 files changed, 41 insertions, 7 deletions
diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h index 4cf1fbe8d1bc..00fef0064355 100644 --- a/include/linux/posix-timers.h +++ b/include/linux/posix-timers.h @@ -82,9 +82,14 @@ static inline bool cpu_timer_enqueue(struct timerqueue_head *head, return timerqueue_add(head, &ctmr->node); } +static inline bool cpu_timer_queued(struct cpu_timer *ctmr) +{ + return !!ctmr->head; +} + static inline bool cpu_timer_dequeue(struct cpu_timer *ctmr) { - if (ctmr->head) { + if (cpu_timer_queued(ctmr)) { timerqueue_del(ctmr->head, &ctmr->node); ctmr->head = NULL; return true; diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index 0d918117a3e0..ee736861b18f 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -419,6 +419,20 @@ static struct posix_cputimer_base *timer_base(struct k_itimer *timer, } /* + * Force recalculating the base earliest expiration on the next tick. + * This will also re-evaluate the need to keep around the process wide + * cputime counter and tick dependency and eventually shut these down + * if necessary. + */ +static void trigger_base_recalc_expires(struct k_itimer *timer, + struct task_struct *tsk) +{ + struct posix_cputimer_base *base = timer_base(timer, tsk); + + base->nextevt = 0; +} + +/* * Dequeue the timer and reset the base if it was its earliest expiration. * It makes sure the next tick recalculates the base next expiration so we * don't keep the costly process wide cputime counter around for a random @@ -438,7 +452,7 @@ static void disarm_timer(struct k_itimer *timer, struct task_struct *p) base = timer_base(timer, p); if (cpu_timer_getexpires(ctmr) == base->nextevt) - base->nextevt = 0; + trigger_base_recalc_expires(timer, p); } @@ -734,13 +748,28 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags, timer->it_overrun_last = 0; timer->it_overrun = -1; - if (new_expires != 0 && !(val < new_expires)) { + if (val >= new_expires) { + if (new_expires != 0) { + /* + * The designated time already passed, so we notify + * immediately, even if the thread never runs to + * accumulate more time on this clock. + */ + cpu_timer_fire(timer); + } + /* - * The designated time already passed, so we notify - * immediately, even if the thread never runs to - * accumulate more time on this clock. + * Make sure we don't keep around the process wide cputime + * counter or the tick dependency if they are not necessary. */ - cpu_timer_fire(timer); + sighand = lock_task_sighand(p, &flags); + if (!sighand) + goto out; + + if (!cpu_timer_queued(ctmr)) + trigger_base_recalc_expires(timer, p); + + unlock_task_sighand(p, &flags); } out: rcu_read_unlock(); |