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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 05:38:53 +0900
commit699d26ccee4e22e324468e94eb648cc89964a15d (patch)
treea1fddfd614fe43b48b42d934d55891dcbf34ae55
parentc5a3f2e9981b6da91e70765d0a958a0ac9d14a53 (diff)
downloadlwn-699d26ccee4e22e324468e94eb648cc89964a15d.tar.gz
lwn-699d26ccee4e22e324468e94eb648cc89964a15d.zip
h8300: Add missing RCU idle APIs on idle loop
commit b2fe1430d4115c74d007c825cb9dc3317f28bb16 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 h8300's idle loop. Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> 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/h8300/kernel/process.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/h8300/kernel/process.c b/arch/h8300/kernel/process.c
index 0e9c315be104..f153ed1a4c08 100644
--- a/arch/h8300/kernel/process.c
+++ b/arch/h8300/kernel/process.c
@@ -36,6 +36,7 @@
#include <linux/reboot.h>
#include <linux/fs.h>
#include <linux/slab.h>
+#include <linux/rcupdate.h>
#include <asm/uaccess.h>
#include <asm/traps.h>
@@ -78,8 +79,10 @@ void (*idle)(void) = default_idle;
void cpu_idle(void)
{
while (1) {
+ rcu_idle_enter();
while (!need_resched())
idle();
+ rcu_idle_exit();
schedule_preempt_disabled();
}
}