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authorPaul E. McKenney <paul.mckenney@linaro.org>2012-08-24 13:22:13 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-09-23 07:44:52 -0700
commit93482f4ef1093f5961a63359a34612183d6beea0 (patch)
tree7dbba89f5cb77b25c55b2be66cd456a7068a0c90
parent11ad47a0edbd62bfc0547cfcdf227a911433f207 (diff)
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@intel.com> Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Cc: <stable@vger.kernel.org> # 3.3+ Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested by: Tony Luck <tony.luck@intel.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
-rw-r--r--arch/ia64/kernel/process.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index dd6fc1449741..3e316ec0b835 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))