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authorPaul E. McKenney <paul.mckenney@linaro.org>2012-08-24 13:22:13 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-10-13 05:50:30 +0900
commiteeb8209162b3d61b4e3cddb9935f5c8dfe097fb4 (patch)
treea113be41146e2b132c2035f7aeff2dd193dd5d09
parent2a853d7062c3598e2fa68a6614cd953164dcaf3e (diff)
ia64: Add missing RCU idle APIs on idle loop
commit 93482f4ef1093f5961a63359a34612183d6beea0 upstream. 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> 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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))