perf, cpu hotplug: Use cached value of smp_processor_id()
The perf_cpu_notifier() macro invokes smp_processor_id()
multiple times. Optimize it by using a local variable.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: peterz@infradead.org
Cc: acme@ghostprotocols.net
Link: http://lkml.kernel.org/r/20121016075817.3572.76733.stgit@srivatsabhat.in.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 0647805..6bfb2faa 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -803,15 +803,16 @@
do { \
static struct notifier_block fn##_nb __cpuinitdata = \
{ .notifier_call = fn, .priority = CPU_PRI_PERF }; \
+ unsigned long cpu = smp_processor_id(); \
unsigned long flags; \
fn(&fn##_nb, (unsigned long)CPU_UP_PREPARE, \
- (void *)(unsigned long)smp_processor_id()); \
+ (void *)(unsigned long)cpu); \
local_irq_save(flags); \
fn(&fn##_nb, (unsigned long)CPU_STARTING, \
- (void *)(unsigned long)smp_processor_id()); \
+ (void *)(unsigned long)cpu); \
local_irq_restore(flags); \
fn(&fn##_nb, (unsigned long)CPU_ONLINE, \
- (void *)(unsigned long)smp_processor_id()); \
+ (void *)(unsigned long)cpu); \
register_cpu_notifier(&fn##_nb); \
} while (0)