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Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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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
This commit is contained in:
Linus Torvalds
2012-06-04 11:25:31 -07:00
parent 0640113be2 62cf20b32a
commit c22072bdf0
7 changed files with 442 additions and 2 deletions
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3
kernel/time/clockevents.c
View File

@@ -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;

18
kernel/time/tick-sched.c
View File

@@ -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,