diff options
Diffstat (limited to 'kernel/time/timer.c')
| -rw-r--r-- | kernel/time/timer.c | 45 |
1 files changed, 24 insertions, 21 deletions
diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 4a4fd567fb26..fa49cd753dea 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -581,7 +581,7 @@ trigger_dyntick_cpu(struct timer_base *base, struct timer_list *timer) * wheel: */ base->next_expiry = timer->expires; - wake_up_nohz_cpu(base->cpu); + wake_up_nohz_cpu(base->cpu); } static void @@ -1251,18 +1251,18 @@ EXPORT_SYMBOL(try_to_del_timer_sync); * * Note: For !irqsafe timers, you must not hold locks that are held in * interrupt context while calling this function. Even if the lock has - * nothing to do with the timer in question. Here's why: + * nothing to do with the timer in question. Here's why:: * * CPU0 CPU1 * ---- ---- - * <SOFTIRQ> - * call_timer_fn(); - * base->running_timer = mytimer; - * spin_lock_irq(somelock); + * <SOFTIRQ> + * call_timer_fn(); + * base->running_timer = mytimer; + * spin_lock_irq(somelock); * <IRQ> * spin_lock(somelock); - * del_timer_sync(mytimer); - * while (base->running_timer == mytimer); + * del_timer_sync(mytimer); + * while (base->running_timer == mytimer); * * Now del_timer_sync() will never return and never release somelock. * The interrupt on the other CPU is waiting to grab somelock but @@ -1657,6 +1657,22 @@ static inline void __run_timers(struct timer_base *base) raw_spin_lock_irq(&base->lock); + /* + * timer_base::must_forward_clk must be cleared before running + * timers so that any timer functions that call mod_timer() will + * not try to forward the base. Idle tracking / clock forwarding + * logic is only used with BASE_STD timers. + * + * The must_forward_clk flag is cleared unconditionally also for + * the deferrable base. The deferrable base is not affected by idle + * tracking and never forwarded, so clearing the flag is a NOOP. + * + * The fact that the deferrable base is never forwarded can cause + * large variations in granularity for deferrable timers, but they + * can be deferred for long periods due to idle anyway. + */ + base->must_forward_clk = false; + while (time_after_eq(jiffies, base->clk)) { levels = collect_expired_timers(base, heads); @@ -1676,19 +1692,6 @@ static __latent_entropy void run_timer_softirq(struct softirq_action *h) { struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]); - /* - * must_forward_clk must be cleared before running timers so that any - * timer functions that call mod_timer will not try to forward the - * base. idle trcking / clock forwarding logic is only used with - * BASE_STD timers. - * - * The deferrable base does not do idle tracking at all, so we do - * not forward it. This can result in very large variations in - * granularity for deferrable timers, but they can be deferred for - * long periods due to idle. - */ - base->must_forward_clk = false; - __run_timers(base); if (IS_ENABLED(CONFIG_NO_HZ_COMMON)) __run_timers(this_cpu_ptr(&timer_bases[BASE_DEF])); |