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authorIngo Molnar <mingo@kernel.org>2016-07-07 10:35:28 +0200
committerIngo Molnar <mingo@kernel.org>2016-07-07 10:35:28 +0200
commit4b4b20852d1009c5e8bc357b22353b62e3a241c7 (patch)
tree1026418471fe10c5b9f2fdff8a6b49bf070938fc /kernel/time/tick-sched.c
parent5130213721d01b6632c255d4295a8102cbb58379 (diff)
parentf00c0afdfa625165a609513bc74164d56752ec3e (diff)
Merge branch 'timers/fast-wheel' into timers/core
Diffstat (limited to 'kernel/time/tick-sched.c')
-rw-r--r--kernel/time/tick-sched.c45
1 files changed, 13 insertions, 32 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index db57d1ba73eb..2ec7c00228f3 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -700,6 +700,12 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,
delta = next_tick - basemono;
if (delta <= (u64)TICK_NSEC) {
tick.tv64 = 0;
+
+ /*
+ * Tell the timer code that the base is not idle, i.e. undo
+ * the effect of get_next_timer_interrupt():
+ */
+ timer_clear_idle();
/*
* We've not stopped the tick yet, and there's a timer in the
* next period, so no point in stopping it either, bail.
@@ -809,6 +815,12 @@ static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now)
tick_do_update_jiffies64(now);
cpu_load_update_nohz_stop();
+ /*
+ * Clear the timer idle flag, so we avoid IPIs on remote queueing and
+ * the clock forward checks in the enqueue path:
+ */
+ timer_clear_idle();
+
calc_load_exit_idle();
touch_softlockup_watchdog_sched();
/*
@@ -1092,35 +1104,6 @@ static void tick_nohz_switch_to_nohz(void)
tick_nohz_activate(ts, NOHZ_MODE_LOWRES);
}
-/*
- * When NOHZ is enabled and the tick is stopped, we need to kick the
- * tick timer from irq_enter() so that the jiffies update is kept
- * alive during long running softirqs. That's ugly as hell, but
- * correctness is key even if we need to fix the offending softirq in
- * the first place.
- *
- * Note, this is different to tick_nohz_restart. We just kick the
- * timer and do not touch the other magic bits which need to be done
- * when idle is left.
- */
-static void tick_nohz_kick_tick(struct tick_sched *ts, ktime_t now)
-{
-#if 0
- /* Switch back to 2.6.27 behaviour */
- ktime_t delta;
-
- /*
- * Do not touch the tick device, when the next expiry is either
- * already reached or less/equal than the tick period.
- */
- delta = ktime_sub(hrtimer_get_expires(&ts->sched_timer), now);
- if (delta.tv64 <= tick_period.tv64)
- return;
-
- tick_nohz_restart(ts, now);
-#endif
-}
-
static inline void tick_nohz_irq_enter(void)
{
struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
@@ -1131,10 +1114,8 @@ static inline void tick_nohz_irq_enter(void)
now = ktime_get();
if (ts->idle_active)
tick_nohz_stop_idle(ts, now);
- if (ts->tick_stopped) {
+ if (ts->tick_stopped)
tick_nohz_update_jiffies(now);
- tick_nohz_kick_tick(ts, now);
- }
}
#else