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authorFrederic Weisbecker <fweisbec@gmail.com>2012-08-22 19:27:34 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-10-13 00:38:54 +0400
commita3e9082a19d723e7be0bc51d851b5689eee67c9c (patch)
tree59f40e60f3ef8171ce7347058abfb8f54b3d20b6
parent3b30d3182fbf026578fbad09877d78c338562f4c (diff)
downloadlinux-a3e9082a19d723e7be0bc51d851b5689eee67c9c.tar.xz
cris: Add missing RCU idle APIs on idle loop
commit c633f9e788928e91ad11f44df29b47bbbe9550b0 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 Cris's idle loop. Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Cris <linux-cris-kernel@axis.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>
-rw-r--r--arch/cris/kernel/process.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/cris/kernel/process.c b/arch/cris/kernel/process.c
index 891dad85e8bd..c722027d69ad 100644
--- a/arch/cris/kernel/process.c
+++ b/arch/cris/kernel/process.c
@@ -25,6 +25,7 @@
#include <linux/elfcore.h>
#include <linux/mqueue.h>
#include <linux/reboot.h>
+#include <linux/rcupdate.h>
//#define DEBUG
@@ -102,6 +103,7 @@ void cpu_idle (void)
{
/* endless idle loop with no priority at all */
while (1) {
+ rcu_idle_enter();
while (!need_resched()) {
void (*idle)(void);
/*
@@ -114,6 +116,7 @@ void cpu_idle (void)
idle = default_idle;
idle();
}
+ rcu_idle_exit();
schedule_preempt_disabled();
}
}