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From: Christoph Lameter <clameter@sgi.com>
To: akpm@osdl.org
Cc: Peter Williams <pwil3058@bigpond.net.au>,
	linux-kernel@vger.kernel.org,
	Nick Piggin <nickpiggin@yahoo.com.au>,
	Christoph Lameter <clameter@sgi.com>,
	"Siddha, Suresh B" <suresh.b.siddha@intel.com>,
	"Chen, Kenneth W" <kenneth.w.chen@intel.com>,
	Ingo Molnar <mingo@elte.hu>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Subject: [PATCH 1/8] Avoid taking rq lock in wake_priority_sleeper
Date: Tue, 14 Nov 2006 12:33:01 -0800 (PST)	[thread overview]
Message-ID: <20061114203301.12761.56852.sendpatchset@schroedinger.engr.sgi.com> (raw)
In-Reply-To: <20061114203256.12761.33911.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-rc5-mm1/kernel/sched.c
===================================================================
--- linux-2.6.19-rc5-mm1.orig/kernel/sched.c	2006-11-13 14:23:24.244457947 -0600
+++ linux-2.6.19-rc5-mm1/kernel/sched.c	2006-11-13 14:23:29.984173185 -0600
@@ -2918,6 +2918,9 @@ 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:[~2006-11-14 20:33 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-11-14 20:32 [PATCH 0/8] sched_domain balancing via softirq V4 Christoph Lameter
2006-11-14 20:33 ` Christoph Lameter [this message]
2006-11-14 20:33 ` [PATCH 2/8] Remove staggering of load balancing Christoph Lameter
2006-11-14 20:33 ` [PATCH 3/8] Disable interrupts for locking in load_balance() Christoph Lameter
2006-11-14 20:33 ` [PATCH 4/8] Extract load calculation from rebalance_tick Christoph Lameter
2006-11-14 20:33 ` [PATCH 5/8] Move idle status calculation into rebalance_tick() Christoph Lameter
2006-11-14 20:33 ` [PATCH 6/8] Use softirq for load balancing Christoph Lameter
2006-11-14 20:33 ` [PATCH 7/8] Call tasklet less frequently Christoph Lameter
2006-11-14 20:33 ` [PATCH 8/8] Add option to serialize load balancing Christoph Lameter
2006-11-14 20:33 ` [DEBUG] Add a few scheduler event counters Christoph Lameter

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