diff options
Diffstat (limited to 'kernel/time/timer.c')
| -rw-r--r-- | kernel/time/timer.c | 49 |
1 files changed, 41 insertions, 8 deletions
diff --git a/kernel/time/timer.c b/kernel/time/timer.c index c16c48de01c5..658051c97a3c 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1252,8 +1252,8 @@ static void expire_timers(struct timer_base *base, struct hlist_head *head) } } -static int collect_expired_timers(struct timer_base *base, - struct hlist_head *heads) +static int __collect_expired_timers(struct timer_base *base, + struct hlist_head *heads) { unsigned long clk = base->clk; struct hlist_head *vec; @@ -1279,9 +1279,9 @@ static int collect_expired_timers(struct timer_base *base, #ifdef CONFIG_NO_HZ_COMMON /* - * Find the next pending bucket of a level. Search from @offset + @clk upwards - * and if nothing there, search from start of the level (@offset) up to - * @offset + clk. + * Find the next pending bucket of a level. Search from level start (@offset) + * + @clk upwards and if nothing there, search from start of the level + * (@offset) up to @offset + clk. */ static int next_pending_bucket(struct timer_base *base, unsigned offset, unsigned clk) @@ -1298,14 +1298,14 @@ static int next_pending_bucket(struct timer_base *base, unsigned offset, } /* - * Search the first expiring timer in the various clock levels. + * Search the first expiring timer in the various clock levels. Caller must + * hold base->lock. */ static unsigned long __next_timer_interrupt(struct timer_base *base) { unsigned long clk, next, adj; unsigned lvl, offset = 0; - spin_lock(&base->lock); next = base->clk + NEXT_TIMER_MAX_DELTA; clk = base->clk; for (lvl = 0; lvl < LVL_DEPTH; lvl++, offset += LVL_SIZE) { @@ -1358,7 +1358,6 @@ static unsigned long __next_timer_interrupt(struct timer_base *base) clk >>= LVL_CLK_SHIFT; clk += adj; } - spin_unlock(&base->lock); return next; } @@ -1416,7 +1415,10 @@ u64 get_next_timer_interrupt(unsigned long basej, u64 basem) if (cpu_is_offline(smp_processor_id())) return expires; + spin_lock(&base->lock); nextevt = __next_timer_interrupt(base); + spin_unlock(&base->lock); + if (time_before_eq(nextevt, basej)) expires = basem; else @@ -1424,6 +1426,37 @@ u64 get_next_timer_interrupt(unsigned long basej, u64 basem) return cmp_next_hrtimer_event(basem, expires); } + +static int collect_expired_timers(struct timer_base *base, + struct hlist_head *heads) +{ + /* + * NOHZ optimization. After a long idle sleep we need to forward the + * base to current jiffies. Avoid a loop by searching the bitfield for + * the next expiring timer. + */ + if ((long)(jiffies - base->clk) > 2) { + unsigned long next = __next_timer_interrupt(base); + + /* + * If the next timer is ahead of time forward to current + * jiffies, otherwise forward to the next expiry time. + */ + if (time_after(next, jiffies)) { + /* The call site will increment clock! */ + base->clk = jiffies - 1; + return 0; + } + base->clk = next; + } + return __collect_expired_timers(base, heads); +} +#else +static inline int collect_expired_timers(struct timer_base *base, + struct hlist_head *heads) +{ + return __collect_expired_timers(base, heads); +} #endif /* |