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Message-ID: <tip-zah5eyn9gu7qlgwh9r6n2anc@git.kernel.org>
Date: Tue, 11 Mar 2014 05:41:51 -0700
From: tip-bot for Peter Zijlstra <tipbot@...or.com>
To: linux-tip-commits@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...nel.org,
peterz@...radead.org, tglx@...utronix.de
Subject: [tip:core/locking] locking/mutexes: Add extra reschedule point
Commit-ID: 34c6bc2c919a55e5ad4e698510a2f35ee13ab900
Gitweb: http://git.kernel.org/tip/34c6bc2c919a55e5ad4e698510a2f35ee13ab900
Author: Peter Zijlstra <peterz@...radead.org>
AuthorDate: Mon, 3 Feb 2014 16:21:09 +0100
Committer: Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 11 Mar 2014 12:14:59 +0100
locking/mutexes: Add extra reschedule point
Add in an extra reschedule in an attempt to avoid getting reschedule
the moment we've acquired the lock.
Signed-off-by: Peter Zijlstra <peterz@...radead.org>
Link: http://lkml.kernel.org/n/tip-zah5eyn9gu7qlgwh9r6n2anc@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
kernel/locking/mutex.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 2670b84..02c61a9 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -468,6 +468,13 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
}
osq_unlock(&lock->osq);
slowpath:
+ /*
+ * If we fell out of the spin path because of need_resched(),
+ * reschedule now, before we try-lock the mutex. This avoids getting
+ * scheduled out right after we obtained the mutex.
+ */
+ if (need_resched())
+ schedule_preempt_disabled();
#endif
spin_lock_mutex(&lock->wait_lock, flags);
--
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