sched: remove extra call overhead for schedule()
Lai Jiangshan's patch reminded me that I promised Nick to remove
that extra call overhead in schedule().
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20090313112300.927414207@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/mutex.c b/kernel/mutex.c
index 5d79781..e1fb735 100644
--- a/kernel/mutex.c
+++ b/kernel/mutex.c
@@ -248,7 +248,9 @@
/* didnt get the lock, go to sleep: */
spin_unlock_mutex(&lock->wait_lock, flags);
- __schedule();
+ preempt_enable_no_resched();
+ schedule();
+ preempt_disable();
spin_lock_mutex(&lock->wait_lock, flags);
}
diff --git a/kernel/sched.c b/kernel/sched.c
index 7601cee..797f6fd 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -5131,13 +5131,15 @@
/*
* schedule() is the main scheduler function.
*/
-asmlinkage void __sched __schedule(void)
+asmlinkage void __sched schedule(void)
{
struct task_struct *prev, *next;
unsigned long *switch_count;
struct rq *rq;
int cpu;
+need_resched:
+ preempt_disable();
cpu = smp_processor_id();
rq = cpu_rq(cpu);
rcu_qsctr_inc(cpu);
@@ -5194,15 +5196,9 @@
if (unlikely(reacquire_kernel_lock(current) < 0))
goto need_resched_nonpreemptible;
-}
-asmlinkage void __sched schedule(void)
-{
-need_resched:
- preempt_disable();
- __schedule();
preempt_enable_no_resched();
- if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
+ if (need_resched())
goto need_resched;
}
EXPORT_SYMBOL(schedule);