diff options
| -rw-r--r-- | include/linux/posix-timers.h | 4 | ||||
| -rw-r--r-- | kernel/time/posix-cpu-timers.c | 33 |
2 files changed, 35 insertions, 2 deletions
diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h index 896c16d2c5fb..4cf1fbe8d1bc 100644 --- a/include/linux/posix-timers.h +++ b/include/linux/posix-timers.h @@ -82,12 +82,14 @@ static inline bool cpu_timer_enqueue(struct timerqueue_head *head, return timerqueue_add(head, &ctmr->node); } -static inline void cpu_timer_dequeue(struct cpu_timer *ctmr) +static inline bool cpu_timer_dequeue(struct cpu_timer *ctmr) { if (ctmr->head) { timerqueue_del(ctmr->head, &ctmr->node); ctmr->head = NULL; + return true; } + return false; } static inline u64 cpu_timer_getexpires(struct cpu_timer *ctmr) diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index 4693d3c71e7e..61c78b62fe6a 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -408,6 +408,37 @@ static int posix_cpu_timer_create(struct k_itimer *new_timer) } /* + * 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 + * amount of time, along with the tick dependency. + * + * If another timer gets queued between this and the next tick, its + * expiration will update the base next event if necessary on the next + * tick. + */ +static void disarm_timer(struct k_itimer *timer, struct task_struct *p) +{ + struct cpu_timer *ctmr = &timer->it.cpu; + struct posix_cputimer_base *base; + int clkidx; + + if (!cpu_timer_dequeue(ctmr)) + return; + + clkidx = CPUCLOCK_WHICH(timer->it_clock); + + if (CPUCLOCK_PERTHREAD(timer->it_clock)) + base = p->posix_cputimers.bases + clkidx; + else + base = p->signal->posix_cputimers.bases + clkidx; + + if (cpu_timer_getexpires(ctmr) == base->nextevt) + base->nextevt = 0; +} + + +/* * Clean up a CPU-clock timer that is about to be destroyed. * This is called from timer deletion with the timer already locked. * If we return TIMER_RETRY, it's necessary to release the timer's lock @@ -441,7 +472,7 @@ static int posix_cpu_timer_del(struct k_itimer *timer) if (timer->it.cpu.firing) ret = TIMER_RETRY; else - cpu_timer_dequeue(ctmr); + disarm_timer(timer, p); unlock_task_sighand(p, &flags); } |