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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 07:44:49 -0700
commitfbe752188d5589e7fcbb8e79824e560f77dccc92 (patch)
tree898b03595514dc9d9c0bccdc4e16fc2ab73f34ac /arch/parisc/kernel
parent5b0753a90b7a98bc613c3767e9263a1a76d4f900 (diff)
downloadvexpress-lsk-fbe752188d5589e7fcbb8e79824e560f77dccc92.tar.gz
parisc: 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 parisc's idle loop. Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: James E.J. Bottomley <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: Parisc <linux-parisc@vger.kernel.org> Cc: <stable@vger.kernel.org> # 3.3+ Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'arch/parisc/kernel')
-rw-r--r--arch/parisc/kernel/process.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
index 2c05a9292a8..8c6b6b6561f 100644
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -48,6 +48,7 @@
#include <linux/unistd.h>
#include <linux/kallsyms.h>
#include <linux/uaccess.h>
+#include <linux/rcupdate.h>
#include <asm/io.h>
#include <asm/asm-offsets.h>
@@ -69,8 +70,10 @@ void 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();
check_pgt_cache();
}