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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 05:38:55 +0900
commit4a94001bd83f18ff3f3b998899d250d96f60a503 (patch)
tree12650d0f045c248d429a86c84065a3a42a2808c2
parent1b5124a305593deffd6186540546b8bfba429570 (diff)
score: Add missing RCU idle APIs on idle loop
commit 0ee23fda59740767324b4340247ca41a2f498ca6 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 scores's idle loop. Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Chen Liqin <liqin.chen@sunplusct.com> Cc: Lennox Wu <lennox.wu@gmail.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/score/kernel/process.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/score/kernel/process.c b/arch/score/kernel/process.c
index 2707023c7563..637970cfd3f4 100644
--- a/arch/score/kernel/process.c
+++ b/arch/score/kernel/process.c
@@ -27,6 +27,7 @@
#include <linux/reboot.h>
#include <linux/elfcore.h>
#include <linux/pm.h>
+#include <linux/rcupdate.h>
void (*pm_power_off)(void);
EXPORT_SYMBOL(pm_power_off);
@@ -50,9 +51,10 @@ void __noreturn cpu_idle(void)
{
/* endless idle loop with no priority at all */
while (1) {
+ rcu_idle_enter();
while (!need_resched())
barrier();
-
+ rcu_idle_exit();
schedule_preempt_disabled();
}
}