From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Date: Sun, 21 Aug 2011 01:29:32 +0000 (-0700)
Subject: rcu: Remove rcu_needs_cpu_flush() to avoid false quiescent states
X-Git-Tag: v3.2-rc1~165^2^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e90c53d3e238dd0b7b02964370e8fece1778df96;p=pandora-kernel.git

rcu: Remove rcu_needs_cpu_flush() to avoid false quiescent states

The purpose of rcu_needs_cpu_flush() was to iterate on pushing the
current grace period in order to help the current CPU enter dyntick-idle
mode.  However, this can result in failures if the CPU starts entering
dyntick-idle mode, but then backs out.  In this case, the call to
rcu_pending() from rcu_needs_cpu_flush() might end up announcing a
non-existing quiescent state.

This commit therefore removes rcu_needs_cpu_flush() in favor of letting
the dyntick-idle machinery at the end of the softirq handler push the
loop along via its call to rcu_pending().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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