3.6-stable review patch. If anyone has any objections, please let me know.
------------------ From: Frederic Weisbecker <[email protected]> commit 5b0753a90b7a98bc613c3767e9263a1a76d4f900 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 mn10300's idle loop. Reported-by: Paul E. McKenney <[email protected]> Signed-off-by: Frederic Weisbecker <[email protected]> Cc: David Howells <[email protected]> Cc: Koichi Yasutake <[email protected]> Signed-off-by: Paul E. McKenney <[email protected]> Acked-by: David Howells <[email protected]> Reviewed-by: Josh Triplett <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/mn10300/kernel/process.c | 3 +++ 1 file changed, 3 insertions(+) --- a/arch/mn10300/kernel/process.c +++ b/arch/mn10300/kernel/process.c @@ -25,6 +25,7 @@ #include <linux/err.h> #include <linux/fs.h> #include <linux/slab.h> +#include <linux/rcupdate.h> #include <asm/uaccess.h> #include <asm/pgtable.h> #include <asm/io.h> @@ -107,6 +108,7 @@ void cpu_idle(void) { /* endless idle loop with no priority at all */ for (;;) { + rcu_idle_enter(); while (!need_resched()) { void (*idle)(void); @@ -121,6 +123,7 @@ void cpu_idle(void) } idle(); } + rcu_idle_exit(); schedule_preempt_disabled(); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
