Commit-ID: 93482f4ef1093f5961a63359a34612183d6beea0
Gitweb: http://git.kernel.org/tip/93482f4ef1093f5961a63359a34612183d6beea0
Author: Paul E. McKenney <paul.mckenney@xxxxxxxxxx>
AuthorDate: Fri, 24 Aug 2012 13:22:13 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Sun, 23 Sep 2012 07:44:52 -0700
ia64: Add missing RCU idle APIs on idle loop
Traditionally, the entire idle task served as an RCU quiescent state.
But when RCU read side critical sections started appearing within the
idle loop, this traditional strategy became untenable. The fix was to
create new RCU APIs named rcu_idle_enter() and rcu_idle_exit(), which
must be called by each architecture's idle loop so that RCU can tell
when it is safe to ignore a given idle CPU.
Unfortunately, this fix was never applied to ia64, a shortcoming remedied
by this commit.
Reported by: Tony Luck <tony.luck@xxxxxxxxx>
Signed-off-by: Paul E. McKenney <paul.mckenney@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # 3.3+
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Tested by: Tony Luck <tony.luck@xxxxxxxxx>
Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
---
arch/ia64/kernel/process.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index dd6fc14..3e316ec 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -29,6 +29,7 @@
#include <linux/kdebug.h>
#include <linux/utsname.h>
#include <linux/tracehook.h>
+#include <linux/rcupdate.h>
#include <asm/cpu.h>
#include <asm/delay.h>
@@ -279,6 +280,7 @@ cpu_idle (void)
/* endless idle loop with no priority at all */
while (1) {
+ rcu_idle_enter();
if (can_do_pal_halt) {
current_thread_info()->status &= ~TS_POLLING;
/*
@@ -309,6 +311,7 @@ cpu_idle (void)
normal_xtp();
#endif
}
+ rcu_idle_exit();
schedule_preempt_disabled();
check_pgt_cache();
if (cpu_is_offline(cpu))
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|