From: Jason Low Date: Tue, 28 Jan 2014 19:13:12 +0000 (-0800) Subject: locking/mutexes: Return false if task need_resched() in mutex_can_spin_on_owner() X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=46af29e479cc0c1c63633007993af5292c2c3e75;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git 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 Signed-off-by: Peter Zijlstra 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 --- diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index 4f408be39a07..e6d646b18d6c 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)