From f46481d0a7cb942b84145acb80ad43bdb1ff8eb4 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 25 Mar 2015 13:11:04 +0100 Subject: [PATCH] tick/xen: Provide and use tick_suspend_local() and tick_resume_local() Xen calls on every cpu into tick_resume() which is just wrong. tick_resume() is for the syscore global suspend/resume invocation. What XEN really wants is a per cpu local resume function. Provide a tick_resume_local() function and use it in XEN. Also provide a complementary tick_suspend_local() and modify tick_unfreeze() and tick_freeze(), respectively, to use the new local tick resume/suspend functions. Signed-off-by: Thomas Gleixner [ Combined two patches, rebased, modified subject/changelog. ] Signed-off-by: Rafael J. Wysocki Cc: Boris Ostrovsky Cc: David Vrabel Cc: Konrad Rzeszutek Wilk Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1698741.eezk9tnXtG@vostro.rjw.lan [ Merged to latest timers/core. ] Signed-off-by: Ingo Molnar --- arch/x86/xen/suspend.c | 2 +- include/linux/tick.h | 6 ++--- kernel/time/tick-broadcast.c | 24 +++++++++++++------ kernel/time/tick-common.c | 55 ++++++++++++++++++++++++++++++-------------- kernel/time/tick-internal.h | 8 +++++-- 5 files changed, 65 insertions(+), 30 deletions(-) diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c index 033e428..d949769 100644 --- a/arch/x86/xen/suspend.c +++ b/arch/x86/xen/suspend.c @@ -85,7 +85,7 @@ static void xen_vcpu_notify_restore(void *data) if (smp_processor_id() == 0) return; - tick_resume(); + tick_resume_local(); } void xen_arch_resume(void) diff --git a/include/linux/tick.h b/include/linux/tick.h index 7e07e0e..a3d4d28 100644 --- a/include/linux/tick.h +++ b/include/linux/tick.h @@ -29,13 +29,13 @@ extern struct tick_device *tick_get_device(int cpu); extern void __init tick_init(void); extern void tick_freeze(void); extern void tick_unfreeze(void); -/* Should be core only, but XEN resume magic abuses this interface */ -extern void tick_resume(void); +/* Should be core only, but XEN resume magic requires this */ +extern void tick_resume_local(void); #else /* CONFIG_GENERIC_CLOCKEVENTS */ static inline void tick_init(void) { } static inline void tick_freeze(void) { } static inline void tick_unfreeze(void) { } -static inline void tick_resume(void) { } +static inline void tick_resume_local(void) { } #endif /* !CONFIG_GENERIC_CLOCKEVENTS */ #ifdef CONFIG_TICK_ONESHOT diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 60e6c23..19cfb38 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -455,11 +455,26 @@ void tick_suspend_broadcast(void) raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); } -int tick_resume_broadcast(void) +/* + * This is called from tick_resume_local() on a resuming CPU. That's + * called from the core resume function, tick_unfreeze() and the magic XEN + * resume hackery. + * + * In none of these cases the broadcast device mode can change and the + * bit of the resuming CPU in the broadcast mask is safe as well. + */ +bool tick_resume_check_broadcast(void) +{ + if (tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT) + return false; + else + return cpumask_test_cpu(smp_processor_id(), tick_broadcast_mask); +} + +void tick_resume_broadcast(void) { struct clock_event_device *bc; unsigned long flags; - int broadcast = 0; raw_spin_lock_irqsave(&tick_broadcast_lock, flags); @@ -472,8 +487,6 @@ int tick_resume_broadcast(void) case TICKDEV_MODE_PERIODIC: if (!cpumask_empty(tick_broadcast_mask)) tick_broadcast_start_periodic(bc); - broadcast = cpumask_test_cpu(smp_processor_id(), - tick_broadcast_mask); break; case TICKDEV_MODE_ONESHOT: if (!cpumask_empty(tick_broadcast_mask)) @@ -482,11 +495,8 @@ int tick_resume_broadcast(void) } } raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); - - return broadcast; } - #ifdef CONFIG_TICK_ONESHOT static cpumask_var_t tick_broadcast_oneshot_mask; diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index 1a60c2a..da796d6 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -374,40 +374,32 @@ void tick_shutdown(unsigned int *cpup) } /** - * tick_suspend - Suspend the tick and the broadcast device + * tick_suspend_local - Suspend the local tick device * - * Called from syscore_suspend() via timekeeping_suspend with only one - * CPU online and interrupts disabled or from tick_unfreeze() under - * tick_freeze_lock. + * Called from the local cpu for freeze with interrupts disabled. * * No locks required. Nothing can change the per cpu device. */ -void tick_suspend(void) +static void tick_suspend_local(void) { struct tick_device *td = this_cpu_ptr(&tick_cpu_device); clockevents_shutdown(td->evtdev); - tick_suspend_broadcast(); } /** - * tick_resume - Resume the tick and the broadcast device + * tick_resume_local - Resume the local tick device * - * Called from syscore_resume() via timekeeping_resume with only one - * CPU online and interrupts disabled or from tick_unfreeze() under - * tick_freeze_lock. + * Called from the local CPU for unfreeze or XEN resume magic. * * No locks required. Nothing can change the per cpu device. */ -void tick_resume(void) +void tick_resume_local(void) { - struct tick_device *td; - int broadcast; + struct tick_device *td = this_cpu_ptr(&tick_cpu_device); + bool broadcast = tick_resume_check_broadcast(); - broadcast = tick_resume_broadcast(); - td = this_cpu_ptr(&tick_cpu_device); clockevents_tick_resume(td->evtdev); - if (!broadcast) { if (td->mode == TICKDEV_MODE_PERIODIC) tick_setup_periodic(td->evtdev, 0); @@ -416,6 +408,35 @@ void tick_resume(void) } } +/** + * tick_suspend - Suspend the tick and the broadcast device + * + * Called from syscore_suspend() via timekeeping_suspend with only one + * CPU online and interrupts disabled or from tick_unfreeze() under + * tick_freeze_lock. + * + * No locks required. Nothing can change the per cpu device. + */ +void tick_suspend(void) +{ + tick_suspend_local(); + tick_suspend_broadcast(); +} + +/** + * tick_resume - Resume the tick and the broadcast device + * + * Called from syscore_resume() via timekeeping_resume with only one + * CPU online and interrupts disabled. + * + * No locks required. Nothing can change the per cpu device. + */ +void tick_resume(void) +{ + tick_resume_broadcast(); + tick_resume_local(); +} + static DEFINE_RAW_SPINLOCK(tick_freeze_lock); static unsigned int tick_freeze_depth; @@ -436,7 +457,7 @@ void tick_freeze(void) if (tick_freeze_depth == num_online_cpus()) { timekeeping_suspend(); } else { - tick_suspend(); + tick_suspend_local(); } raw_spin_unlock(&tick_freeze_lock); diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h index 5c9f0ee..6ba7bce 100644 --- a/kernel/time/tick-internal.h +++ b/kernel/time/tick-internal.h @@ -23,6 +23,7 @@ extern void tick_check_new_device(struct clock_event_device *dev); extern void tick_handover_do_timer(int *cpup); extern void tick_shutdown(unsigned int *cpup); extern void tick_suspend(void); +extern void tick_resume(void); extern bool tick_check_replacement(struct clock_event_device *curdev, struct clock_event_device *newdev); extern void tick_install_replacement(struct clock_event_device *dev); @@ -43,6 +44,7 @@ extern int __clockevents_update_freq(struct clock_event_device *dev, u32 freq); extern ssize_t sysfs_get_uname(const char *buf, char *dst, size_t cnt); #else static inline void tick_suspend(void) { } +static inline void tick_resume(void) { } #endif /* GENERIC_CLOCKEVENTS */ /* Oneshot related functions */ @@ -81,7 +83,8 @@ extern int tick_is_broadcast_device(struct clock_event_device *dev); extern void tick_broadcast_on_off(unsigned long reason, int *oncpu); extern void tick_shutdown_broadcast(unsigned int *cpup); extern void tick_suspend_broadcast(void); -extern int tick_resume_broadcast(void); +extern void tick_resume_broadcast(void); +extern bool tick_resume_check_broadcast(void); extern void tick_broadcast_init(void); extern void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast); extern int tick_broadcast_update_freq(struct clock_event_device *dev, u32 freq); @@ -95,7 +98,8 @@ static inline void tick_do_periodic_broadcast(struct clock_event_device *d) { } static inline void tick_broadcast_on_off(unsigned long reason, int *oncpu) { } static inline void tick_shutdown_broadcast(unsigned int *cpup) { } static inline void tick_suspend_broadcast(void) { } -static inline int tick_resume_broadcast(void) { return 0; } +static inline void tick_resume_broadcast(void) { } +static inline bool tick_resume_check_broadcast(void) { return false; } static inline void tick_broadcast_init(void) { } static inline int tick_broadcast_update_freq(struct clock_event_device *dev, u32 freq) { return -ENODEV; } -- 2.7.4