score: Add missing RCU idle APIs on idle loop
authorFrederic Weisbecker <fweisbec@gmail.com>
Wed, 22 Aug 2012 15:27:34 +0000 (17:27 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 12 Oct 2012 20:38:55 +0000 (05:38 +0900)
commit4a94001bd83f18ff3f3b998899d250d96f60a503
tree12650d0f045c248d429a86c84065a3a42a2808c2
parent1b5124a305593deffd6186540546b8bfba429570
score: Add missing RCU idle APIs on idle loop

commit 0ee23fda59740767324b4340247ca41a2f498ca6 upstream.

In the old times, the whole idle task was considered
as an RCU quiescent state. But as RCU became more and
more successful overtime, some RCU read side critical
section have been added even in the code of some
architectures idle tasks, for tracing for example.

So nowadays, rcu_idle_enter() and rcu_idle_exit() must
be called by the architecture to tell RCU about the part
in the idle loop that doesn't make use of rcu read side
critical sections, typically the part that puts the CPU
in low power mode.

This is necessary for RCU to find the quiescent states in
idle in order to complete grace periods.

Add this missing pair of calls in scores's idle loop.

Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chen Liqin <liqin.chen@sunplusct.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/score/kernel/process.c