From cd05a1f818073a623455a58e756c5b419fc98db9 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sat, 17 Mar 2007 00:25:52 +0100 Subject: [PATCH] [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 ++++++++++++++++++++++----- kernel/time/tick-common.c | 13 +++++++------ kernel/time/tick-internal.h | 11 ++++++++++- kernel/time/tick-oneshot.c | 12 ++++++++++++ 4 files changed, 51 insertions(+), 12 deletions(-) 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: * diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index 43ba1bdec14..bfda3f7f071 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -298,18 +298,17 @@ static void tick_shutdown(unsigned int *cpup) spin_unlock_irqrestore(&tick_device_lock, flags); } -static void tick_suspend_periodic(void) +static void tick_suspend(void) { struct tick_device *td = &__get_cpu_var(tick_cpu_device); unsigned long flags; spin_lock_irqsave(&tick_device_lock, flags); - if (td->mode == TICKDEV_MODE_PERIODIC) - clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_SHUTDOWN); + clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_SHUTDOWN); spin_unlock_irqrestore(&tick_device_lock, flags); } -static void tick_resume_periodic(void) +static void tick_resume(void) { struct tick_device *td = &__get_cpu_var(tick_cpu_device); unsigned long flags; @@ -317,6 +316,8 @@ static void tick_resume_periodic(void) spin_lock_irqsave(&tick_device_lock, flags); if (td->mode == TICKDEV_MODE_PERIODIC) tick_setup_periodic(td->evtdev, 0); + else + tick_resume_oneshot(); spin_unlock_irqrestore(&tick_device_lock, flags); } @@ -348,13 +349,13 @@ static int tick_notify(struct notifier_block *nb, unsigned long reason, break; case CLOCK_EVT_NOTIFY_SUSPEND: - tick_suspend_periodic(); + tick_suspend(); tick_suspend_broadcast(); break; case CLOCK_EVT_NOTIFY_RESUME: if (!tick_resume_broadcast()) - tick_resume_periodic(); + tick_resume(); break; default: diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h index 75890efd24f..c9d203bde51 100644 --- a/kernel/time/tick-internal.h +++ b/kernel/time/tick-internal.h @@ -19,12 +19,13 @@ extern void tick_setup_oneshot(struct clock_event_device *newdev, extern int tick_program_event(ktime_t expires, int force); extern void tick_oneshot_notify(void); extern int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *)); - +extern void tick_resume_oneshot(void); # ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST extern void tick_broadcast_setup_oneshot(struct clock_event_device *bc); extern void tick_broadcast_oneshot_control(unsigned long reason); extern void tick_broadcast_switch_to_oneshot(void); extern void tick_shutdown_broadcast_oneshot(unsigned int *cpup); +extern int tick_resume_broadcast_oneshot(struct clock_event_device *bc); # else /* BROADCAST */ static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc) { @@ -43,6 +44,10 @@ void tick_setup_oneshot(struct clock_event_device *newdev, { BUG(); } +static inline void tick_resume_oneshot(void) +{ + BUG(); +} static inline int tick_program_event(ktime_t expires, int force) { return 0; @@ -54,6 +59,10 @@ static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc) } static inline void tick_broadcast_oneshot_control(unsigned long reason) { } static inline void tick_shutdown_broadcast_oneshot(unsigned int *cpup) { } +static inline int tick_resume_broadcast_oneshot(struct clock_event_device *bc) +{ + return 0; +} #endif /* !TICK_ONESHOT */ /* diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c index 2e8b7ff863c..f6997ab0c3c 100644 --- a/kernel/time/tick-oneshot.c +++ b/kernel/time/tick-oneshot.c @@ -40,6 +40,18 @@ int tick_program_event(ktime_t expires, int force) } } +/** + * tick_resume_onshot - resume oneshot mode + */ +void tick_resume_oneshot(void) +{ + struct tick_device *td = &__get_cpu_var(tick_cpu_device); + struct clock_event_device *dev = td->evtdev; + + clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT); + tick_program_event(ktime_get(), 1); +} + /** * tick_setup_oneshot - setup the event device for oneshot mode (hres or nohz) */ -- 2.41.1