From: Eric Dumazet <edumazet@google.com>
Date: Tue, 7 Aug 2012 10:55:45 +0000 (+0000)
Subject: net: force dst_default_metrics to const section
X-Git-Tag: v3.6-rc2~15^2~22
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a37e6e344910a43b9ebc2bbf29a029f5ea942598;p=pandora-kernel.git

net: force dst_default_metrics to const section

While investigating on network performance problems, I found this little
gem :

$ nm -v vmlinux | grep -1 dst_default_metrics
ffffffff82736540 b busy.46605
ffffffff82736560 B dst_default_metrics
ffffffff82736598 b dst_busy_list

Apparently, declaring a const array without initializer put it in
(writeable) bss section, in middle of possibly often dirtied cache
lines.

Since we really want dst_default_metrics be const to avoid any possible
false sharing and catch any buggy writes, I force a null initializer.

ffffffff818a4c20 R dst_default_metrics

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

Reading git-diff-tree failed