Messages in this thread Patch in this message | | | Date | Mon, 10 Feb 2014 20:58:22 +0100 | From | Peter Zijlstra <> | Subject | [PATCH 2/8] mutex: In mutex_can_spin_on_owner(), return false if task need_resched() |
| |
The mutex_can_spin_on_owner() function should also return false if the task needs to be rescheduled to avoid entering the MCS queue when it needs to reschedule.
Cc: chegu_vinod@hp.com Cc: paulmck@linux.vnet.ibm.com Cc: Waiman.Long@hp.com Cc: torvalds@linux-foundation.org Cc: tglx@linutronix.de Cc: riel@redhat.com Cc: akpm@linux-foundation.org Cc: davidlohr@hp.com Cc: hpa@zytor.com Cc: andi@firstfloor.org Cc: aswin@hp.com Cc: mingo@kernel.org Cc: scott.norton@hp.com Signed-off-by: Jason Low <jason.low2@hp.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1390936396-3962-2-git-send-email-jason.low2@hp.com --- kernel/locking/mutex.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -166,6 +166,9 @@ static inline int mutex_can_spin_on_owne struct task_struct *owner; int retval = 1; + if (need_resched()) + return 0; + rcu_read_lock(); owner = ACCESS_ONCE(lock->owner); if (owner)
| |