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From: Gregory Haskins <ghaskins@novell.com>
To: mingo@elte.hu, tglx@linutronix.de, rostedt@goodmis.org,
	linux-rt-users@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, sdietrich@novell.com,
	pmorreale@novell.com, mkohari@novell.com, ghaskins@novell.com
Subject: [PATCH 5/5] remove the extra call to try_to_take_lock
Date: Tue, 20 May 2008 10:49:36 -0400	[thread overview]
Message-ID: <20080520144936.15992.48894.stgit@novell1.haskins.net> (raw)
In-Reply-To: <20080520143954.15992.85900.stgit@novell1.haskins.net>

From: Peter W. Morreale <pmorreale@novell.com>

Remove the redundant attempt to get the lock.  While it is true that the
exit path with this patch adds an un-necessary xchg (in the event the
lock is granted without further traversal in the loop) experimentation
shows that we almost never encounter this situation.

Signed-off-by: Peter W. Morreale <pmorreale@novell.com>
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
---

 kernel/rtmutex.c |    6 ------
 1 files changed, 0 insertions(+), 6 deletions(-)

diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
index ec1f7d4..1da7813 100644
--- a/kernel/rtmutex.c
+++ b/kernel/rtmutex.c
@@ -785,12 +785,6 @@ rt_spin_lock_slowlock(struct rt_mutex *lock)
 	spin_lock_irqsave(&lock->wait_lock, flags);
 	init_lists(lock);
 
-	/* Try to acquire the lock again: */
-	if (do_try_to_take_rt_mutex(lock, STEAL_LATERAL)) {
-		spin_unlock_irqrestore(&lock->wait_lock, flags);
-		return;
-	}
-
 	BUG_ON(rt_mutex_owner(lock) == current);
 
 	/*


  parent reply	other threads:[~2008-05-20 15:23 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-05-20 14:49 [PATCH 0/5] RT: adaptive-lock enhancements Gregory Haskins
2008-05-20 14:49 ` [PATCH 1/5] optimize rt lock wakeup Gregory Haskins
2008-05-20 14:49 ` [PATCH 2/5] sched: make task->oncpu available in all configurations Gregory Haskins
2008-05-20 14:49 ` [PATCH 3/5] rtmutex: use task->oncpu to save a call Gregory Haskins
2008-05-20 14:49 ` [PATCH 4/5] adjust pi_lock usage in wakeup Gregory Haskins
2008-05-20 14:49 ` Gregory Haskins [this message]
2008-05-24  3:02   ` [PATCH 5/5] remove the extra call to try_to_take_lock Steven Rostedt
2008-05-24  3:30     ` Gregory Haskins
2008-05-24 14:11       ` Peter W. Morreale

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