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Commit 46af29e4 authored by Jason Low's avatar Jason Low Committed by Ingo Molnar
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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: default avatarJason Low <jason.low2@hp.com>
Signed-off-by: default avatarPeter 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: default avatarIngo Molnar <mingo@kernel.org>
parent c9122da1

kernel/locking/mutex.c

+3 −0
Original line number Diff line number Diff line
@@ -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)