From 3c4fbe5e01d7e5309be5045e7ae0db20a049e6dc Mon Sep 17 00:00:00 2001 From: Miao Xie Date: Wed, 20 Aug 2008 16:37:38 -0700 Subject: nohz: fix wrong event handler after online an offlined cpu On the tickless system(CONFIG_NO_HZ=y and CONFIG_HIGH_RES_TIMERS=n), after I made an offlined cpu online, I found this cpu's event handler was tick_handle_periodic, not tick_nohz_handler. After debuging, I found this bug was caused by the wrong tick mode. the tick mode is not changed to NOHZ_MODE_INACTIVE when the cpu is offline. This patch fixes this bug. Signed-off-by: Miao Xie Signed-off-by: Andrew Morton Signed-off-by: Ingo Molnar --- kernel/time/tick-sched.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'kernel/time') diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index f5da526424a..7a46bde78c6 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -643,17 +643,21 @@ void tick_setup_sched_timer(void) ts->nohz_mode = NOHZ_MODE_HIGHRES; #endif } +#endif /* HIGH_RES_TIMERS */ +#if defined CONFIG_NO_HZ || defined CONFIG_HIGH_RES_TIMERS void tick_cancel_sched_timer(int cpu) { struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); +# ifdef CONFIG_HIGH_RES_TIMERS if (ts->sched_timer.base) hrtimer_cancel(&ts->sched_timer); +# endif ts->nohz_mode = NOHZ_MODE_INACTIVE; } -#endif /* HIGH_RES_TIMERS */ +#endif /** * Async notification about clocksource changes -- cgit v1.2.3 From 56c7426b3951e4f35a71d695f1c982989399d6fd Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 1 Sep 2008 16:44:23 +0200 Subject: sched_clock: fix NOHZ interaction If HLT stops the TSC, we'll fail to account idle time, thereby inflating the actual process times. Fix this by re-calibrating the clock against GTOD when leaving nohz mode. Signed-off-by: Peter Zijlstra Tested-by: Avi Kivity Signed-off-by: Ingo Molnar --- kernel/time/tick-sched.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel/time') diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 7a46bde78c6..a87b0468568 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -162,6 +162,8 @@ void tick_nohz_stop_idle(int cpu) ts->idle_lastupdate = now; ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta); ts->idle_active = 0; + + sched_clock_idle_wakeup_event(0); } } @@ -177,6 +179,7 @@ static ktime_t tick_nohz_start_idle(struct tick_sched *ts) } ts->idle_entrytime = now; ts->idle_active = 1; + sched_clock_idle_sleep_event(); return now; } -- cgit v1.2.3