Messages in this thread Patch in this message | | | Date | Tue, 11 Mar 2014 05:41:00 -0700 | From | tip-bot for Jason Low <> | Subject | [tip:core/locking] locking/mutexes: Return false if task need_resched() in mutex_can_spin_on_owner() |
| |
Commit-ID: 46af29e479cc0c1c63633007993af5292c2c3e75 Gitweb: http://git.kernel.org/tip/46af29e479cc0c1c63633007993af5292c2c3e75 Author: Jason Low <jason.low2@hp.com> AuthorDate: Tue, 28 Jan 2014 11:13:12 -0800 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Tue, 11 Mar 2014 12:14:52 +0100
locking/mutexes: Return false if task need_resched() in mutex_can_spin_on_owner()
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.
Signed-off-by: Jason Low <jason.low2@hp.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> 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: scott.norton@hp.com Cc: chegu_vinod@hp.com Cc: paulmck@linux.vnet.ibm.com Link: http://lkml.kernel.org/r/1390936396-3962-2-git-send-email-jason.low2@hp.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- kernel/locking/mutex.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index 4f408be..e6d646b 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -166,6 +166,9 @@ static inline int mutex_can_spin_on_owner(struct mutex *lock) struct task_struct *owner; int retval = 1; + if (need_resched()) + return 0; + rcu_read_lock(); owner = ACCESS_ONCE(lock->owner); if (owner)
| |