Re: [PATCH -v7][RFC]: mutex: implement adaptive spinning
From: Peter Zijlstra <peterz@infradead.org>
Date: 2009-01-09 18:16:04
Also in:
linux-fsdevel, lkml
Possibly related (same subject, not in this thread)
- 2009-01-12 · Re: [PATCH -v7][RFC]: mutex: implement adaptive spinning · Ingo Molnar <hidden>
- 2009-01-12 · Re: [PATCH -v7][RFC]: mutex: implement adaptive spinning · Jamie Lokier <hidden>
- 2009-01-11 · Re: [PATCH -v7][RFC]: mutex: implement adaptive spinning · Linus Torvalds <torvalds@linux-foundation.org>
- 2009-01-11 · Re: [PATCH -v7][RFC]: mutex: implement adaptive spinning · Andi Kleen <hidden>
- 2009-01-11 · Re: [PATCH -v7][RFC]: mutex: implement adaptive spinning · David Woodhouse <dwmw2@infradead.org>
On Fri, 2009-01-09 at 11:44 -0500, Steven Rostedt wrote:
When we get to the schedule() it then needs to be a: preempt_enable_no_resched(); schedule();
On that note: Index: linux-2.6/kernel/mutex.c ===================================================================
--- linux-2.6.orig/kernel/mutex.c
+++ linux-2.6/kernel/mutex.c@@ -220,7 +220,9 @@ __mutex_lock_common(struct mutex *lock, __set_task_state(task, state); /* didnt get the lock, go to sleep: */ + preempt_disable(); spin_unlock_mutex(&lock->wait_lock, flags); + preempt_enable_no_resched(); schedule(); spin_lock_mutex(&lock->wait_lock, flags); }
actually improves mutex performance on PREEMPT=y