diff options
| -rw-r--r-- | include/linux/timer.h | 1 | ||||
| -rw-r--r-- | kernel/time/timer.c | 45 |
2 files changed, 39 insertions, 7 deletions
diff --git a/include/linux/timer.h b/include/linux/timer.h index 9f8895decb82..37b5e2f74d21 100644 --- a/include/linux/timer.h +++ b/include/linux/timer.h @@ -203,6 +203,7 @@ extern void add_timer_on(struct timer_list *timer, int cpu); extern int del_timer(struct timer_list * timer); extern int mod_timer(struct timer_list *timer, unsigned long expires); extern int mod_timer_pending(struct timer_list *timer, unsigned long expires); +extern int timer_reduce(struct timer_list *timer, unsigned long expires); /* * The jiffies value which is added to now, when there is no timer diff --git a/kernel/time/timer.c b/kernel/time/timer.c index fbb1f85327bf..af0b8bae4502 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -929,8 +929,11 @@ static struct timer_base *lock_timer_base(struct timer_list *timer, } } +#define MOD_TIMER_PENDING_ONLY 0x01 +#define MOD_TIMER_REDUCE 0x02 + static inline int -__mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only) +__mod_timer(struct timer_list *timer, unsigned long expires, unsigned int options) { struct timer_base *base, *new_base; unsigned int idx = UINT_MAX; @@ -950,7 +953,11 @@ __mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only) * larger granularity than you would get from adding a new * timer with this expiry. */ - if (timer->expires == expires) + long diff = timer->expires - expires; + + if (!diff) + return 1; + if (options & MOD_TIMER_REDUCE && diff <= 0) return 1; /* @@ -962,6 +969,12 @@ __mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only) base = lock_timer_base(timer, &flags); forward_timer_base(base); + if (timer_pending(timer) && (options & MOD_TIMER_REDUCE) && + time_before_eq(timer->expires, expires)) { + ret = 1; + goto out_unlock; + } + clk = base->clk; idx = calc_wheel_index(expires, clk); @@ -971,7 +984,10 @@ __mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only) * subsequent call will exit in the expires check above. */ if (idx == timer_get_idx(timer)) { - timer->expires = expires; + if (!(options & MOD_TIMER_REDUCE)) + timer->expires = expires; + else if (time_after(timer->expires, expires)) + timer->expires = expires; ret = 1; goto out_unlock; } @@ -981,7 +997,7 @@ __mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only) } ret = detach_if_pending(timer, base, false); - if (!ret && pending_only) + if (!ret && (options & MOD_TIMER_PENDING_ONLY)) goto out_unlock; debug_activate(timer, expires); @@ -1042,7 +1058,7 @@ out_unlock: */ int mod_timer_pending(struct timer_list *timer, unsigned long expires) { - return __mod_timer(timer, expires, true); + return __mod_timer(timer, expires, MOD_TIMER_PENDING_ONLY); } EXPORT_SYMBOL(mod_timer_pending); @@ -1068,11 +1084,26 @@ EXPORT_SYMBOL(mod_timer_pending); */ int mod_timer(struct timer_list *timer, unsigned long expires) { - return __mod_timer(timer, expires, false); + return __mod_timer(timer, expires, 0); } EXPORT_SYMBOL(mod_timer); /** + * timer_reduce - Modify a timer's timeout if it would reduce the timeout + * @timer: The timer to be modified + * @expires: New timeout in jiffies + * + * timer_reduce() is very similar to mod_timer(), except that it will only + * modify a running timer if that would reduce the expiration time (it will + * start a timer that isn't running). + */ +int timer_reduce(struct timer_list *timer, unsigned long expires) +{ + return __mod_timer(timer, expires, MOD_TIMER_REDUCE); +} +EXPORT_SYMBOL(timer_reduce); + +/** * add_timer - start a timer * @timer: the timer to be added * @@ -1754,7 +1785,7 @@ signed long __sched schedule_timeout(signed long timeout) timer.task = current; timer_setup_on_stack(&timer.timer, process_timeout, 0); - __mod_timer(&timer.timer, expire, false); + __mod_timer(&timer.timer, expire, 0); schedule(); del_singleshot_timer_sync(&timer.timer); |