From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Sun, 25 Jan 2009 20:50:13 +0000 (-0800)
Subject: x86: micro-optimize __raw_read_trylock()
X-Git-Tag: v2.6.30-rc1~211^2~26^2~2^2~166^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2d4d57db692ea790e185656516e6ebe8791f1788;p=pandora-kernel.git

x86: micro-optimize __raw_read_trylock()

The current version of __raw_read_trylock starts with decrementing the lock
and read its new value as a separate operation after that.

That makes 3 dereferences (read, write (after sub), read) whereas
a single atomic_dec_return does only two pointers dereferences (read, write).

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

Reading git-diff-tree failed