From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Date: Thu, 4 Sep 2014 19:21:41 +0000 (-0700)
Subject: rcu: Use DEFINE_PER_CPU_SHARED_ALIGNED for rcu_data
X-Git-Tag: omap-for-v3.19/fixes-rc1~168^2^2^2~8
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=11bbb235c26f93b7c69e441452e44adbf6ed6996;p=pandora-kernel.git

rcu: Use DEFINE_PER_CPU_SHARED_ALIGNED for rcu_data

The rcu_data per-CPU variable has a number of fields that are atomically
manipulated, potentially by any CPU.  This situation can result in false
sharing with per-CPU variables that have the misfortune of being allocated
adjacent to rcu_data in memory.  This commit therefore changes the
DEFINE_PER_CPU() to DEFINE_PER_CPU_SHARED_ALIGNED() in order to avoid
this false sharing.

Reported-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>
---

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