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authorFrederic Weisbecker <fweisbec@gmail.com>2012-08-22 17:27:34 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-10-13 05:38:54 +0900
commitc7cc1fa9594f1c7fe4de4418dbe9d85c3a4727ee (patch)
tree8c6176883facd4d9f08a72b64f939e812f1de840 /arch/mn10300
parentc272355732aaf718ba4c05b0693c0d327ea0de45 (diff)
mn10300: Add missing RCU idle APIs on idle loop
commit 5b0753a90b7a98bc613c3767e9263a1a76d4f900 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 mn10300's idle loop. Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: David Howells <dhowells@redhat.com> Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: David Howells <dhowells@redhat.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/mn10300')
-rw-r--r--arch/mn10300/kernel/process.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/mn10300/kernel/process.c b/arch/mn10300/kernel/process.c
index 14707f25153b..675d8f2c32e9 100644
--- a/arch/mn10300/kernel/process.c
+++ b/arch/mn10300/kernel/process.c
@@ -25,6 +25,7 @@
#include <linux/err.h>
#include <linux/fs.h>
#include <linux/slab.h>
+#include <linux/rcupdate.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/io.h>
@@ -107,6 +108,7 @@ void cpu_idle(void)
{
/* endless idle loop with no priority at all */
for (;;) {
+ rcu_idle_enter();
while (!need_resched()) {
void (*idle)(void);
@@ -121,6 +123,7 @@ void cpu_idle(void)
}
idle();
}
+ rcu_idle_exit();
schedule_preempt_disabled();
}