| From fc932ffc87196b4ba8233d3095f0f5bc57b57f7a Mon Sep 17 00:00:00 2001 |
| From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| Date: Wed, 13 Jul 2016 18:22:23 +0200 |
| Subject: [PATCH] timer: make the base lock raw |
| |
| The part where the base lock is held got more predictable / shorter after the |
| timer rework. One reason is the lack of re-cascading. |
| That means the lock can be made raw and held in IRQ context. |
| |
| Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| |
| diff --git a/kernel/time/timer.c b/kernel/time/timer.c |
| index 36cec054b8ae..dfc7eef2753c 100644 |
| --- a/kernel/time/timer.c |
| +++ b/kernel/time/timer.c |
| @@ -195,7 +195,7 @@ EXPORT_SYMBOL(jiffies_64); |
| #endif |
| |
| struct timer_base { |
| - spinlock_t lock; |
| + raw_spinlock_t lock; |
| struct timer_list *running_timer; |
| unsigned long clk; |
| unsigned long next_expiry; |
| @@ -920,10 +920,10 @@ static struct timer_base *lock_timer_base(struct timer_list *timer, |
| |
| if (!(tf & TIMER_MIGRATING)) { |
| base = get_timer_base(tf); |
| - spin_lock_irqsave(&base->lock, *flags); |
| + raw_spin_lock_irqsave(&base->lock, *flags); |
| if (timer->flags == tf) |
| return base; |
| - spin_unlock_irqrestore(&base->lock, *flags); |
| + raw_spin_unlock_irqrestore(&base->lock, *flags); |
| } |
| cpu_relax(); |
| } |
| @@ -1000,9 +1000,9 @@ __mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only) |
| /* See the comment in lock_timer_base() */ |
| timer->flags |= TIMER_MIGRATING; |
| |
| - spin_unlock(&base->lock); |
| + raw_spin_unlock(&base->lock); |
| base = new_base; |
| - spin_lock(&base->lock); |
| + raw_spin_lock(&base->lock); |
| WRITE_ONCE(timer->flags, |
| (timer->flags & ~TIMER_BASEMASK) | base->cpu); |
| forward_timer_base(base); |
| @@ -1025,7 +1025,7 @@ __mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only) |
| } |
| |
| out_unlock: |
| - spin_unlock_irqrestore(&base->lock, flags); |
| + raw_spin_unlock_irqrestore(&base->lock, flags); |
| |
| return ret; |
| } |
| @@ -1118,9 +1118,9 @@ void add_timer_on(struct timer_list *timer, int cpu) |
| if (base != new_base) { |
| timer->flags |= TIMER_MIGRATING; |
| |
| - spin_unlock(&base->lock); |
| + raw_spin_unlock(&base->lock); |
| base = new_base; |
| - spin_lock(&base->lock); |
| + raw_spin_lock(&base->lock); |
| WRITE_ONCE(timer->flags, |
| (timer->flags & ~TIMER_BASEMASK) | cpu); |
| } |
| @@ -1128,7 +1128,7 @@ void add_timer_on(struct timer_list *timer, int cpu) |
| |
| debug_activate(timer, timer->expires); |
| internal_add_timer(base, timer); |
| - spin_unlock_irqrestore(&base->lock, flags); |
| + raw_spin_unlock_irqrestore(&base->lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(add_timer_on); |
| |
| @@ -1154,7 +1154,7 @@ int del_timer(struct timer_list *timer) |
| if (timer_pending(timer)) { |
| base = lock_timer_base(timer, &flags); |
| ret = detach_if_pending(timer, base, true); |
| - spin_unlock_irqrestore(&base->lock, flags); |
| + raw_spin_unlock_irqrestore(&base->lock, flags); |
| } |
| |
| return ret; |
| @@ -1181,7 +1181,7 @@ int try_to_del_timer_sync(struct timer_list *timer) |
| if (base->running_timer != timer) |
| ret = detach_if_pending(timer, base, true); |
| |
| - spin_unlock_irqrestore(&base->lock, flags); |
| + raw_spin_unlock_irqrestore(&base->lock, flags); |
| |
| return ret; |
| } |
| @@ -1312,13 +1312,13 @@ static void expire_timers(struct timer_base *base, struct hlist_head *head) |
| data = timer->data; |
| |
| if (timer->flags & TIMER_IRQSAFE) { |
| - spin_unlock(&base->lock); |
| + raw_spin_unlock(&base->lock); |
| call_timer_fn(timer, fn, data); |
| - spin_lock(&base->lock); |
| + raw_spin_lock(&base->lock); |
| } else { |
| - spin_unlock_irq(&base->lock); |
| + raw_spin_unlock_irq(&base->lock); |
| call_timer_fn(timer, fn, data); |
| - spin_lock_irq(&base->lock); |
| + raw_spin_lock_irq(&base->lock); |
| } |
| } |
| } |
| @@ -1487,7 +1487,7 @@ u64 get_next_timer_interrupt(unsigned long basej, u64 basem) |
| if (cpu_is_offline(smp_processor_id())) |
| return expires; |
| |
| - spin_lock(&base->lock); |
| + raw_spin_lock(&base->lock); |
| nextevt = __next_timer_interrupt(base); |
| is_max_delta = (nextevt == base->clk + NEXT_TIMER_MAX_DELTA); |
| base->next_expiry = nextevt; |
| @@ -1521,7 +1521,7 @@ u64 get_next_timer_interrupt(unsigned long basej, u64 basem) |
| base->is_idle = true; |
| } |
| } |
| - spin_unlock(&base->lock); |
| + raw_spin_unlock(&base->lock); |
| |
| return cmp_next_hrtimer_event(basem, expires); |
| } |
| @@ -1609,7 +1609,7 @@ static inline void __run_timers(struct timer_base *base) |
| if (!time_after_eq(jiffies, base->clk)) |
| return; |
| |
| - spin_lock_irq(&base->lock); |
| + raw_spin_lock_irq(&base->lock); |
| |
| while (time_after_eq(jiffies, base->clk)) { |
| |
| @@ -1620,7 +1620,7 @@ static inline void __run_timers(struct timer_base *base) |
| expire_timers(base, heads + levels); |
| } |
| base->running_timer = NULL; |
| - spin_unlock_irq(&base->lock); |
| + raw_spin_unlock_irq(&base->lock); |
| } |
| |
| /* |
| @@ -1818,16 +1818,16 @@ int timers_dead_cpu(unsigned int cpu) |
| * The caller is globally serialized and nobody else |
| * takes two locks at once, deadlock is not possible. |
| */ |
| - spin_lock_irq(&new_base->lock); |
| - spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING); |
| + raw_spin_lock_irq(&new_base->lock); |
| + raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING); |
| |
| BUG_ON(old_base->running_timer); |
| |
| for (i = 0; i < WHEEL_SIZE; i++) |
| migrate_timer_list(new_base, old_base->vectors + i); |
| |
| - spin_unlock(&old_base->lock); |
| - spin_unlock_irq(&new_base->lock); |
| + raw_spin_unlock(&old_base->lock); |
| + raw_spin_unlock_irq(&new_base->lock); |
| put_cpu_ptr(&timer_bases); |
| } |
| return 0; |
| @@ -1843,7 +1843,7 @@ static void __init init_timer_cpu(int cpu) |
| for (i = 0; i < NR_BASES; i++) { |
| base = per_cpu_ptr(&timer_bases[i], cpu); |
| base->cpu = cpu; |
| - spin_lock_init(&base->lock); |
| + raw_spin_lock_init(&base->lock); |
| base->clk = jiffies; |
| } |
| } |
| -- |
| 2.1.4 |
| |