Messages in this thread Patch in this message | | | From | "Rafael J. Wysocki" <> | Subject | [PATCH 2/8] PM / Sleep: Use wait queue to signal "no wakeup events in progress" | Date | Sun, 22 Apr 2012 23:20:39 +0200 |
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From: Rafael J. Wysocki <rjw@sisk.pl>
The current wakeup source deactivation code doesn't do anything when the counter of wakeup events in progress goes down to zero, which requires pm_get_wakeup_count() to poll that counter periodically. Although this reduces the average time it takes to deactivate a wakeup source, it also may lead to a substantial amount of unnecessary polling if there are extended periods of wakeup activity. Thus it seems reasonable to use a wait queue for signaling the "no wakeup events in progress" condition and remove the polling.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> --- drivers/base/power/wakeup.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)
Index: linux/drivers/base/power/wakeup.c =================================================================== --- linux.orig/drivers/base/power/wakeup.c +++ linux/drivers/base/power/wakeup.c @@ -17,8 +17,6 @@ #include "power.h" -#define TIMEOUT 100 - /* * If set, the suspend/hibernate code will abort transitions to a sleep state * if wakeup events are registered during or immediately before the transition. @@ -52,6 +50,8 @@ static void pm_wakeup_timer_fn(unsigned static LIST_HEAD(wakeup_sources); +static DECLARE_WAIT_QUEUE_HEAD(wakeup_count_wait_queue); + /** * wakeup_source_prepare - Prepare a new wakeup source for initialization. * @ws: Wakeup source to prepare. @@ -442,6 +442,7 @@ EXPORT_SYMBOL_GPL(pm_stay_awake); */ static void wakeup_source_deactivate(struct wakeup_source *ws) { + unsigned int cnt, inpr; ktime_t duration; ktime_t now; @@ -476,6 +477,10 @@ static void wakeup_source_deactivate(str * couter of wakeup events in progress simultaneously. */ atomic_add(MAX_IN_PROGRESS, &combined_event_count); + + split_counters(&cnt, &inpr); + if (!inpr && waitqueue_active(&wakeup_count_wait_queue)) + wake_up(&wakeup_count_wait_queue); } /** @@ -667,14 +672,19 @@ bool pm_wakeup_pending(void) bool pm_get_wakeup_count(unsigned int *count) { unsigned int cnt, inpr; + DEFINE_WAIT(wait); for (;;) { + prepare_to_wait(&wakeup_count_wait_queue, &wait, + TASK_INTERRUPTIBLE); split_counters(&cnt, &inpr); if (inpr == 0 || signal_pending(current)) break; pm_wakeup_update_hit_counts(); - schedule_timeout_interruptible(msecs_to_jiffies(TIMEOUT)); + + schedule(); } + finish_wait(&wakeup_count_wait_queue, &wait); split_counters(&cnt, &inpr); *count = cnt;
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