From: Theodore Ts'o <tytso@mit.edu>
Date: Sun, 16 May 2010 09:00:00 +0000 (-0400)
Subject: jbd2: Improve scalability by not taking j_state_lock in jbd2_journal_stop()
X-Git-Tag: v2.6.35-rc1~39^2~27
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c35a56a090eacefca07afeb994029b57d8dd8025;p=pandora-kernel.git

jbd2: Improve scalability by not taking j_state_lock in jbd2_journal_stop()

One of the most contended locks in the jbd2 layer is j_state_lock when
running dbench.  This is especially true if using the real-time kernel
with its "sleeping spinlocks" patch that replaces spinlocks with
priority inheriting mutexes --- but it also shows up on large SMP
benchmarks.

Thanks to John Stultz for pointing this out.

Reviewed by Mingming Cao and Jan Kara.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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