From: Benjamin LaHaise <bcrl@kvack.org>
Date: Wed, 30 Jan 2008 12:33:13 +0000 (+0100)
Subject: x86: fix synchronize_rcu(): high latency on idle system
X-Git-Tag: v2.6.25-rc1~1143^2~283
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0723a69a63beec1ca6e792239ef75d0181387ef0;p=pandora-kernel.git

x86: fix synchronize_rcu(): high latency on idle system

an otherwise idle system takes about 3 ticks per network
interface in unregister_netdev() due to multiple calls to synchronize_rcu(),
which adds up to quite a few seconds for tearing down thousands of
interfaces.  By flushing pending rcu callbacks in the idle loop, the system
makes progress hundreds of times faster.  If this is indeed a sane thing to,
it probably needs to be done for other architectures than x86.  And yes, the
network stack shouldn't call synchronize_rcu() quite so much, but fixing that
is a little more involved.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---

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