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From: Christoph Lameter <clameter@sgi.com>
To: akpm@osdl.org
Cc: Christoph Lameter <clameter@sgi.com>, linux-kernel@vger.kernel.org
Subject: [PATCH 1/7] Avoid taking rq lock in wake_priority_sleeper
Date: Fri, 3 Nov 2006 12:46:41 -0800 (PST)	[thread overview]
Message-ID: <20061103204641.15739.87085.sendpatchset@schroedinger.engr.sgi.com> (raw)
In-Reply-To: <20061103204636.15739.74831.sendpatchset@schroedinger.engr.sgi.com>

Avoid taking the rq lock in wake_priority sleeper

Avoid taking the request queue lock in wake_priority_sleeper if
there are no running processes.

Signed-off-by: Christoph Lameter <clameter@sgi.com>

Index: linux-2.6.19-rc4-mm2/kernel/sched.c
===================================================================
--- linux-2.6.19-rc4-mm2.orig/kernel/sched.c	2006-11-02 17:31:05.964060772 -0600
+++ linux-2.6.19-rc4-mm2/kernel/sched.c	2006-11-03 12:51:15.281805162 -0600
@@ -2899,6 +2899,9 @@ static inline int wake_priority_sleeper(
 	int ret = 0;
 
 #ifdef CONFIG_SCHED_SMT
+	if (!rq->nr_running)
+		return 0;
+
 	spin_lock(&rq->lock);
 	/*
 	 * If an SMT sibling task has been put to sleep for priority

  reply	other threads:[~2006-11-03 20:46 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-11-03 20:46 [PATCH 0/7] sched_domain balancing via tasklet V3 Christoph Lameter
2006-11-03 20:46 ` Christoph Lameter [this message]
2006-11-03 20:46 ` [PATCH 2/7] Disable interrupts for locking in load_balance() Christoph Lameter
2006-11-03 20:46 ` [PATCH 3/7] Extract load calculation from rebalance_tick Christoph Lameter
2006-11-03 20:46 ` [PATCH 4/7] Stagger load balancing in build_sched_domains Christoph Lameter
2006-11-03 20:47 ` [PATCH 5/7] Move idle stat calculation into rebalance_tick() Christoph Lameter
2006-11-03 20:47 ` [PATCH 6/7] Use tasklet to call balancing Christoph Lameter
2006-11-03 20:47 ` [PATCH 7/7] Call tasklet less frequently Christoph Lameter
  -- strict thread matches above, loose matches on Subject: below --
2006-10-28  2:41 [PATCH 0/7] sched_domain balancing via tasklet V2 Christoph Lameter
2006-10-28  2:41 ` [PATCH 1/7] Avoid taking rq lock in wake_priority_sleeper Christoph Lameter

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