Hi Greg,
Thanks for adding it.
Signed-off-by: Chris Zankel <[email protected]>
On 10/10/2012 03:52 PM, Greg Kroah-Hartman wrote:
3.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Frederic Weisbecker <[email protected]>
commit 11ad47a0edbd62bfc0547cfcdf227a911433f207 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 xtensa's idle loop.
Reported-by: Paul E. McKenney <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Chris Zankel <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Reviewed-by: Josh Triplett <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/xtensa/kernel/process.c | 3 +++
1 file changed, 3 insertions(+)
--- a/arch/xtensa/kernel/process.c
+++ b/arch/xtensa/kernel/process.c
@@ -31,6 +31,7 @@
#include <linux/mqueue.h>
#include <linux/fs.h>
#include <linux/slab.h>
+#include <linux/rcupdate.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
@@ -110,8 +111,10 @@ void cpu_idle(void)
/* endless idle loop with no priority at all */
while (1) {
+ rcu_idle_enter();
while (!need_resched())
platform_idle();
+ rcu_idle_exit();
schedule_preempt_disabled();
}
}
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