diff options
| -rw-r--r-- | include/linux/timer.h | 1 | ||||
| -rw-r--r-- | kernel/timer.c | 65 |
2 files changed, 58 insertions, 8 deletions
diff --git a/include/linux/timer.h b/include/linux/timer.h index 719113b652d..e0c5c16c992 100644 --- a/include/linux/timer.h +++ b/include/linux/timer.h @@ -37,6 +37,7 @@ extern struct tvec_t_base_s boot_tvec_bases; TIMER_INITIALIZER(_function, _expires, _data) void fastcall init_timer(struct timer_list * timer); +void fastcall init_timer_deferrable(struct timer_list *timer); static inline void setup_timer(struct timer_list * timer, void (*function)(unsigned long), diff --git a/kernel/timer.c b/kernel/timer.c index b22bd39740d..dbe966feff2 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -74,7 +74,7 @@ struct tvec_t_base_s { tvec_t tv3; tvec_t tv4; tvec_t tv5; -} ____cacheline_aligned_in_smp; +} ____cacheline_aligned; typedef struct tvec_t_base_s tvec_base_t; @@ -82,6 +82,37 @@ tvec_base_t boot_tvec_bases; EXPORT_SYMBOL(boot_tvec_bases); static DEFINE_PER_CPU(tvec_base_t *, tvec_bases) = &boot_tvec_bases; +/* + * Note that all tvec_bases is 2 byte aligned and lower bit of + * base in timer_list is guaranteed to be zero. Use the LSB for + * the new flag to indicate whether the timer is deferrable + */ +#define TBASE_DEFERRABLE_FLAG (0x1) + +/* Functions below help us manage 'deferrable' flag */ +static inline unsigned int tbase_get_deferrable(tvec_base_t *base) +{ + return ((unsigned int)(unsigned long)base & TBASE_DEFERRABLE_FLAG); +} + +static inline tvec_base_t *tbase_get_base(tvec_base_t *base) +{ + return ((tvec_base_t *)((unsigned long)base & ~TBASE_DEFERRABLE_FLAG)); +} + +static inline void timer_set_deferrable(struct timer_list *timer) +{ + timer->base = ((tvec_base_t *)((unsigned long)(timer->base) | + TBASE_DEFERRABLE_FLAG)); +} + +static inline void +timer_set_base(struct timer_list *timer, tvec_base_t *new_base) +{ + timer->base = (tvec_base_t *)((unsigned long)(new_base) | + tbase_get_deferrable(timer->base)); +} + /** * __round_jiffies - function to round jiffies to a full second * @j: the time in (absolute) jiffies that should be rounded @@ -295,6 +326,13 @@ void fastcall init_timer(struct timer_list *timer) } EXPORT_SYMBOL(init_timer); +void fastcall init_timer_deferrable(struct timer_list *timer) +{ + init_timer(timer); + timer_set_deferrable(timer); +} +EXPORT_SYMBOL(init_timer_deferrable); + static inline void detach_timer(struct timer_list *timer, int clear_pending) { @@ -325,10 +363,11 @@ static tvec_base_t *lock_timer_base(struct timer_list *timer, tvec_base_t *base; for (;;) { - base = timer->base; + tvec_base_t *prelock_base = timer->base; + base = tbase_get_base(prelock_base); if (likely(base != NULL)) { spin_lock_irqsave(&base->lock, *flags); - if (likely(base == timer->base)) + if (likely(prelock_base == timer->base)) return base; /* The timer has migrated to another CPU */ spin_unlock_irqrestore(&base->lock, *flags); @@ -365,11 +404,11 @@ int __mod_timer(struct timer_list *timer, unsigned long expires) */ if (likely(base->running_timer != timer)) { /* See the comment in lock_timer_base() */ - timer->base = NULL; + timer_set_base(timer, NULL); spin_unlock(&base->lock); base = new_base; spin_lock(&base->lock); - timer->base = base; + timer_set_base(timer, base); } } @@ -397,7 +436,7 @@ void add_timer_on(struct timer_list *timer, int cpu) timer_stats_timer_set_start_info(timer); BUG_ON(timer_pending(timer) || !timer->function); spin_lock_irqsave(&base->lock, flags); - timer->base = base; + timer_set_base(timer, base); internal_add_timer(base, timer); spin_unlock_irqrestore(&base->lock, flags); } @@ -550,7 +589,7 @@ static int cascade(tvec_base_t *base, tvec_t *tv, int index) * don't have to detach them individually. */ list_for_each_entry_safe(timer, tmp, &tv_list, entry) { - BUG_ON(timer->base != base); + BUG_ON(tbase_get_base(timer->base) != base); internal_add_timer(base, timer); } @@ -636,6 +675,9 @@ static unsigned long __next_timer_interrupt(tvec_base_t *base) index = slot = timer_jiffies & TVR_MASK; do { list_for_each_entry(nte, base->tv1.vec + slot, entry) { + if (tbase_get_deferrable(nte->base)) + continue; + found = 1; expires = nte->expires; /* Look at the cascade bucket(s)? */ @@ -1617,6 +1659,13 @@ static int __devinit init_timers_cpu(int cpu) cpu_to_node(cpu)); if (!base) return -ENOMEM; + + /* Make sure that tvec_base is 2 byte aligned */ + if (tbase_get_deferrable(base)) { + WARN_ON(1); + kfree(base); + return -ENOMEM; + } memset(base, 0, sizeof(*base)); per_cpu(tvec_bases, cpu) = base; } else { @@ -1658,7 +1707,7 @@ static void migrate_timer_list(tvec_base_t *new_base, struct list_head *head) while (!list_empty(head)) { timer = list_entry(head->next, struct timer_list, entry); detach_timer(timer, 0); - timer->base = new_base; + timer_set_base(timer, new_base); internal_add_timer(new_base, timer); } } |