From: David S. Miller <davem@davemloft.net>
Date: Wed, 25 Aug 2010 09:27:49 +0000 (-0700)
Subject: tcp: Combat per-cpu skew in orphan tests.
X-Git-Tag: v2.6.36-rc3~2^2~7
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ad1af0fedba14f82b240a03fe20eb9b2fdbd0357;p=pandora-kernel.git

tcp: Combat per-cpu skew in orphan tests.

As reported by Anton Blanchard when we use
percpu_counter_read_positive() to make our orphan socket limit checks,
the check can be off by up to num_cpus_online() * batch (which is 32
by default) which on a 128 cpu machine can be as large as the default
orphan limit itself.

Fix this by doing the full expensive sum check if the optimized check
triggers.

Reported-by: Anton Blanchard <anton@samba.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
---

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