From a3e9082a19d723e7be0bc51d851b5689eee67c9c Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Wed, 22 Aug 2012 17:27:34 +0200 Subject: [PATCH] cris: Add missing RCU idle APIs on idle loop commit c633f9e788928e91ad11f44df29b47bbbe9550b0 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 Cris's idle loop. Reported-by: Paul E. McKenney Signed-off-by: Frederic Weisbecker Cc: Mikael Starvik Cc: Jesper Nilsson Cc: Cris Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett Signed-off-by: Greg Kroah-Hartman --- arch/cris/kernel/process.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/cris/kernel/process.c b/arch/cris/kernel/process.c index 891dad8..c722027 100644 --- a/arch/cris/kernel/process.c +++ b/arch/cris/kernel/process.c @@ -25,6 +25,7 @@ #include #include #include +#include //#define DEBUG @@ -102,6 +103,7 @@ void cpu_idle (void) { /* endless idle loop with no priority at all */ while (1) { + rcu_idle_enter(); while (!need_resched()) { void (*idle)(void); /* @@ -114,6 +116,7 @@ void cpu_idle (void) idle = default_idle; idle(); } + rcu_idle_exit(); schedule_preempt_disabled(); } } -- 2.7.4