From 27185016b806d5a1181ff501cae120582b2b27dd Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 12 Nov 2009 22:12:06 +0100 Subject: nohz: Track last do_timer() cpu The previous patch which limits the sleep time to the maximum deferment time of the time keeping clocksource has some limitations on SMP machines: if all CPUs are idle then for all CPUs the maximum sleep time is limited. Solve this by keeping track of which cpu had the do_timer() duty assigned last and limit the sleep time only for this cpu. Signed-off-by: Thomas Gleixner LKML-Reference: Cc: Jon Hunter Cc: John Stultz --- include/linux/tick.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/tick.h') diff --git a/include/linux/tick.h b/include/linux/tick.h index 8dc082194b22..d2ae79e21be3 100644 --- a/include/linux/tick.h +++ b/include/linux/tick.h @@ -43,6 +43,7 @@ enum tick_nohz_mode { * @idle_exittime: Time when the idle state was left * @idle_sleeptime: Sum of the time slept in idle with sched tick stopped * @sleep_length: Duration of the current idle sleep + * @do_timer_lst: CPU was the last one doing do_timer before going idle */ struct tick_sched { struct hrtimer sched_timer; @@ -64,6 +65,7 @@ struct tick_sched { unsigned long last_jiffies; unsigned long next_jiffies; ktime_t idle_expires; + int do_timer_last; }; extern void __init tick_init(void); -- cgit v1.2.2