From mboxrd@z Thu Jan 1 00:00:00 1970 From: Subject: Patch "alpha: Add missing RCU idle APIs on idle loop" has been added to the 3.5-stable tree Date: Wed, 10 Oct 2012 09:25:11 +0900 Message-ID: <13498287103238@kroah.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: Sender: linux-alpha-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: fweisbec@gmail.com, gregkh@linuxfoundation.org, ink@jurassic.park.msu.ru, josh@joshtriplett.org, linux-alpha@vger.kernel.org, mattst88@gmail.com, mcree@orcon.net.nz, paulmck@linux.vnet.ibm.com, rth@twiddle.net Cc: stable@vger.kernel.org, stable-commits@vger.kernel.org This is a note to let you know that I've just added the patch titled alpha: Add missing RCU idle APIs on idle loop to the 3.5-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: alpha-add-missing-rcu-idle-apis-on-idle-loop.patch and it can be found in the queue-3.5 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >From 4c94cada48f7c660eca582be6032427a5e367117 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Wed, 22 Aug 2012 17:27:34 +0200 Subject: alpha: Add missing RCU idle APIs on idle loop From: Frederic Weisbecker commit 4c94cada48f7c660eca582be6032427a5e367117 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 the Alpha's idle loop. Reported-by: Paul E. McKenney Signed-off-by: Frederic Weisbecker Tested-by: Michael Cree Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Matt Turner Cc: alpha Cc: Paul E. McKenney Reviewed-by: Josh Triplett Signed-off-by: Greg Kroah-Hartman --- arch/alpha/kernel/process.c | 3 +++ 1 file changed, 3 insertions(+) --- a/arch/alpha/kernel/process.c +++ b/arch/alpha/kernel/process.c @@ -28,6 +28,7 @@ #include #include #include +#include #include #include @@ -54,8 +55,10 @@ cpu_idle(void) /* FIXME -- EV6 and LCA45 know how to power down the CPU. */ + rcu_idle_enter(); while (!need_resched()) cpu_relax(); + rcu_idle_exit(); schedule(); } } Patches currently in stable-queue which might be from fweisbec@gmail.com are queue-3.5/frv-add-missing-rcu-idle-apis-on-idle-loop.patch queue-3.5/cris-add-missing-rcu-idle-apis-on-idle-loop.patch queue-3.5/m68k-add-missing-rcu-idle-apis-on-idle-loop.patch queue-3.5/alpha-add-missing-rcu-idle-apis-on-idle-loop.patch queue-3.5/h8300-add-missing-rcu-idle-apis-on-idle-loop.patch queue-3.5/parisc-add-missing-rcu-idle-apis-on-idle-loop.patch queue-3.5/m32r-add-missing-rcu-idle-apis-on-idle-loop.patch queue-3.5/score-add-missing-rcu-idle-apis-on-idle-loop.patch queue-3.5/mn10300-add-missing-rcu-idle-apis-on-idle-loop.patch queue-3.5/xtensa-add-missing-rcu-idle-apis-on-idle-loop.patch