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Subject: timer-handle-idle-trylock-in-get-next-timer-irq.patch
From: Thomas Gleixner <tglx@linutronix.de>
Date: Sun, 17 Jul 2011 22:08:38 +0200
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/spinlock_rt.h | 12 +++++++++++-
kernel/rtmutex.c | 7 +------
kernel/timer.c | 7 ++++---
3 files changed, 16 insertions(+), 10 deletions(-)
Index: linux-stable/include/linux/spinlock_rt.h
===================================================================
--- linux-stable.orig/include/linux/spinlock_rt.h
+++ linux-stable/include/linux/spinlock_rt.h
@@ -53,7 +53,17 @@ extern void __lockfunc __rt_spin_unlock(
#define spin_lock_irq(lock) spin_lock(lock)
-#define spin_trylock(lock) __cond_lock(lock, rt_spin_trylock(lock))
+#define spin_do_trylock(lock) __cond_lock(lock, rt_spin_trylock(lock))
+
+#define spin_trylock(lock) \
+({ \
+ int __locked; \
+ migrate_disable(); \
+ __locked = spin_do_trylock(lock); \
+ if (!__locked) \
+ migrate_enable(); \
+ __locked; \
+})
#ifdef CONFIG_LOCKDEP
# define spin_lock_nested(lock, subclass) \
Index: linux-stable/kernel/rtmutex.c
===================================================================
--- linux-stable.orig/kernel/rtmutex.c
+++ linux-stable/kernel/rtmutex.c
@@ -861,15 +861,10 @@ EXPORT_SYMBOL(rt_spin_unlock_wait);
int __lockfunc rt_spin_trylock(spinlock_t *lock)
{
- int ret;
+ int ret = rt_mutex_trylock(&lock->lock);
- migrate_disable();
- ret = rt_mutex_trylock(&lock->lock);
if (ret)
spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
- else
- migrate_enable();
-
return ret;
}
EXPORT_SYMBOL(rt_spin_trylock);
Index: linux-stable/kernel/timer.c
===================================================================
--- linux-stable.orig/kernel/timer.c
+++ linux-stable/kernel/timer.c
@@ -1393,9 +1393,10 @@ unsigned long get_next_timer_interrupt(u
/*
* On PREEMPT_RT we cannot sleep here. If the trylock does not
* succeed then we return the worst-case 'expires in 1 tick'
- * value:
+ * value. We use the rt functions here directly to avoid a
+ * migrate_disable() call.
*/
- if (!spin_trylock(&base->lock))
+ if (!spin_do_trylock(&base->lock))
return now + 1;
#else
spin_lock(&base->lock);
@@ -1405,7 +1406,7 @@ unsigned long get_next_timer_interrupt(u
base->next_timer = __next_timer_interrupt(base);
expires = base->next_timer;
}
- spin_unlock(&base->lock);
+ rt_spin_unlock(&base->lock);
if (time_before_eq(expires, now))
return now;
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