Commit 46af29e4 authored Jan 28, 2014 by Jason Low Committed by Ingo Molnar Mar 11, 2014

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>

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)

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