diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-06-04 11:25:31 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-06-04 11:25:31 -0700 |
| commit | c22072bdf053b115a1126658100967dda00b5ecf (patch) | |
| tree | 21520119dbbfce237a5005e9840105e86944c9cc /kernel | |
| parent | 0640113be25d283e0ff77a9f041e1242182387f0 (diff) | |
| parent | 62cf20b32aee4ae889a2eb40fd41c0eab73de970 (diff) | |
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Thomas Gleixner:
"The clocksource driver is pure hardware enablement and the skew option
is default off, well tested and non dangerous."
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
tick: Move skew_tick option into the HIGH_RES_TIMER section
clocksource: em_sti: Add DT support
clocksource: em_sti: Emma Mobile STI driver
clockevents: Make clockevents_config() a global symbol
tick: Add tick skew boot option
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/time/clockevents.c | 3 | ||||
| -rw-r--r-- | kernel/time/tick-sched.c | 18 |
2 files changed, 19 insertions, 2 deletions
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index 9cd928f7a7c6..7e1ce012a851 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -297,8 +297,7 @@ void clockevents_register_device(struct clock_event_device *dev) } EXPORT_SYMBOL_GPL(clockevents_register_device); -static void clockevents_config(struct clock_event_device *dev, - u32 freq) +void clockevents_config(struct clock_event_device *dev, u32 freq) { u64 sec; diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 6a3a5b9ff561..efd386667536 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -814,6 +814,16 @@ static enum hrtimer_restart tick_sched_timer(struct hrtimer *timer) return HRTIMER_RESTART; } +static int sched_skew_tick; + +static int __init skew_tick(char *str) +{ + get_option(&str, &sched_skew_tick); + + return 0; +} +early_param("skew_tick", skew_tick); + /** * tick_setup_sched_timer - setup the tick emulation timer */ @@ -831,6 +841,14 @@ void tick_setup_sched_timer(void) /* Get the next period (per cpu) */ hrtimer_set_expires(&ts->sched_timer, tick_init_jiffy_update()); + /* Offset the tick to avert xtime_lock contention. */ + if (sched_skew_tick) { + u64 offset = ktime_to_ns(tick_period) >> 1; + do_div(offset, num_possible_cpus()); + offset *= smp_processor_id(); + hrtimer_add_expires_ns(&ts->sched_timer, offset); + } + for (;;) { hrtimer_forward(&ts->sched_timer, now, tick_period); hrtimer_start_expires(&ts->sched_timer, |