Messages in this thread Patch in this message | | | Date | Tue, 18 Apr 2017 13:11:08 +0200 | From | Thomas Gleixner <> | Subject | [patch V2 06/10] timer: Restructure internal locking |
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Move the locking out from __run_timers() to the call sites, so the protected section can be extended at the call site. Preparatory patch for changing the NOHZ timer placement to a pull at expiry time model.
No functional change.
Signed-off-by: Richard Cochran <rcochran@linutronix.de> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
--- kernel/time/timer.c | 33 +++++++++++++++++++-------------- 1 file changed, 19 insertions(+), 14 deletions(-)
--- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1651,17 +1651,14 @@ void update_process_times(int user_tick) /** * __run_timers - run all expired timers (if any) on this CPU. * @base: the timer vector to be processed. + * + * Caller must hold the base lock. */ static inline void __run_timers(struct timer_base *base) { struct hlist_head heads[LVL_DEPTH]; int levels; - if (!time_after_eq(jiffies, base->clk)) - return; - - spin_lock_irq(&base->lock); - while (time_after_eq(jiffies, base->clk)) { levels = collect_expired_timers(base, heads); @@ -1671,7 +1668,20 @@ static inline void __run_timers(struct t expire_timers(base, heads + levels); } base->running_timer = NULL; - spin_unlock_irq(&base->lock); +} + +static void run_timer_base(int index, bool check_nohz) +{ + struct timer_base *base = this_cpu_ptr(&timer_bases[index]); + + if (check_nohz && !base->nohz_active) + return; + + if (time_after_eq(jiffies, base->clk)) { + spin_lock_irq(&base->lock); + __run_timers(base); + spin_unlock_irq(&base->lock); + } } /* @@ -1679,16 +1689,11 @@ static inline void __run_timers(struct t */ static __latent_entropy void run_timer_softirq(struct softirq_action *h) { - struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_LOCAL]); + run_timer_base(BASE_LOCAL, false); - __run_timers(base); if (IS_ENABLED(CONFIG_NO_HZ_COMMON)) { - base = this_cpu_ptr(&timer_bases[BASE_GLOBAL]); - __run_timers(base); - - base = this_cpu_ptr(&timer_bases[BASE_DEF]); - if (base->nohz_active) - __run_timers(base); + run_timer_base(BASE_GLOBAL, false); + run_timer_base(BASE_DEF, true); } }
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