From cd05a1f818073a623455a58e756c5b419fc98db9 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sat, 17 Mar 2007 00:25:52 +0100 Subject: [PATCH] clockevents: Fix suspend/resume to disk hangs I finally found a dual core box, which survives suspend/resume without crashing in the middle of nowhere. Sigh, I never figured out from the code and the bug reports what's going on. The observed hangs are caused by a stale state transition of the clock event devices, which keeps the RCU synchronization away from completion, when the non boot CPU is brought back up. The suspend/resume in oneshot mode needs the similar care as the periodic mode during suspend to RAM. My assumption that the state transitions during the different shutdown/bringups of s2disk would go through the periodic boot phase and then switch over to highres resp. nohz mode were simply wrong. Add the appropriate suspend / resume handling for the non periodic modes. Signed-off-by: Thomas Gleixner Signed-off-by: Linus Torvalds --- kernel/time/tick-broadcast.c | 27 ++++++++++++++++++++++----- 1 file changed, 22 insertions(+), 5 deletions(-) (limited to 'kernel/time/tick-broadcast.c') diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 5567745470f..eadfce2fff7 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -307,12 +307,19 @@ int tick_resume_broadcast(void) spin_lock_irqsave(&tick_broadcast_lock, flags); bc = tick_broadcast_device.evtdev; - if (bc) { - if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC && - !cpus_empty(tick_broadcast_mask)) - tick_broadcast_start_periodic(bc); - broadcast = cpu_isset(smp_processor_id(), tick_broadcast_mask); + if (bc) { + switch (tick_broadcast_device.mode) { + case TICKDEV_MODE_PERIODIC: + if(!cpus_empty(tick_broadcast_mask)) + tick_broadcast_start_periodic(bc); + broadcast = cpu_isset(smp_processor_id(), + tick_broadcast_mask); + break; + case TICKDEV_MODE_ONESHOT: + broadcast = tick_resume_broadcast_oneshot(bc); + break; + } } spin_unlock_irqrestore(&tick_broadcast_lock, flags); @@ -347,6 +354,16 @@ static int tick_broadcast_set_event(ktime_t expires, int force) } } +int tick_resume_broadcast_oneshot(struct clock_event_device *bc) +{ + clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT); + + if(!cpus_empty(tick_broadcast_oneshot_mask)) + tick_broadcast_set_event(ktime_get(), 1); + + return cpu_isset(smp_processor_id(), tick_broadcast_oneshot_mask); +} + /* * Reprogram the broadcast device: * -- cgit v1.2.3