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authorFrederic Weisbecker <fweisbec@gmail.com>2012-08-22 17:27:34 +0200
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-09-23 07:44:47 -0700
commit48ae077cfce72591b8fc80e1dcc87806f86fed7f (patch)
tree19bf28676bbf912295ae24b8e7d8d4ff4eaf7627
parentb2fe1430d4115c74d007c825cb9dc3317f28bb16 (diff)
m32r: Add missing RCU idle APIs on idle loop
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 m32r's idle loop. Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: <stable@vger.kernel.org> # 3.3+ Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
-rw-r--r--arch/m32r/kernel/process.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/m32r/kernel/process.c b/arch/m32r/kernel/process.c
index 3a4a32b27208..384e63f3a4c4 100644
--- a/arch/m32r/kernel/process.c
+++ b/arch/m32r/kernel/process.c
@@ -26,6 +26,7 @@
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/hardirq.h>
+#include <linux/rcupdate.h>
#include <asm/io.h>
#include <asm/uaccess.h>
@@ -82,6 +83,7 @@ void cpu_idle (void)
{
/* endless idle loop with no priority at all */
while (1) {
+ rcu_idle_enter();
while (!need_resched()) {
void (*idle)(void) = pm_idle;
@@ -90,6 +92,7 @@ void cpu_idle (void)
idle();
}
+ rcu_idle_exit();
schedule_preempt_disabled();
}
}