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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 07:44:45 -0700
commit41d8fe5bb3cf91ce2716ac8f43e4b40d802a99c8 (patch)
tree2855dde9a54bfe768ffca698b07b19f8b414e5db
parentc633f9e788928e91ad11f44df29b47bbbe9550b0 (diff)
downloadlinux-41d8fe5bb3cf91ce2716ac8f43e4b40d802a99c8.tar.bz2
frv: 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 Frv'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: <stable@vger.kernel.org> # 3.3+ Acked-by: David Howells <dhowells@redhat.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
-rw-r--r--arch/frv/kernel/process.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/frv/kernel/process.c b/arch/frv/kernel/process.c
index ff95f50efea5..2eb7fa5bf9d8 100644
--- a/arch/frv/kernel/process.c
+++ b/arch/frv/kernel/process.c
@@ -25,6 +25,7 @@
#include <linux/reboot.h>
#include <linux/interrupt.h>
#include <linux/pagemap.h>
+#include <linux/rcupdate.h>
#include <asm/asm-offsets.h>
#include <asm/uaccess.h>
@@ -69,12 +70,14 @@ void cpu_idle(void)
{
/* endless idle loop with no priority at all */
while (1) {
+ rcu_idle_enter();
while (!need_resched()) {
check_pgt_cache();
if (!frv_dma_inprogress && idle)
idle();
}
+ rcu_idle_exit();
schedule_preempt_disabled();
}