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| author | Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> | 2012-10-16 13:28:17 +0530 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2012-10-24 10:01:59 +0200 |
| commit | c13d38e4a1fd5dd07135403c613c8091af444169 (patch) | |
| tree | 85bdc667286f9c9d4437c2020f2dd0d60a8f2c89 /include/linux/perf_event.h | |
| parent | 6760bca9fd16256210f4922a3e9f067d2c7017d7 (diff) | |
| download | lwn-c13d38e4a1fd5dd07135403c613c8091af444169.tar.gz lwn-c13d38e4a1fd5dd07135403c613c8091af444169.zip | |
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>
Diffstat (limited to 'include/linux/perf_event.h')
| -rw-r--r-- | include/linux/perf_event.h | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 06478056da03..6bfb2faa0b19 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -803,15 +803,16 @@ static inline void perf_event_task_tick(void) { } 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) |