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| author | Eric Dumazet | 2010-11-26 17:22:16 +0100 |
|---|---|---|
| committer | Ingo Molnar | 2010-12-08 20:16:01 +0100 |
| commit | 40dc11ffb35e8c4e8fa71092048e0f8de9db758c (patch) | |
| tree | 88ae143dab98b902b7ec94220160560463c063f9 /kernel | |
| parent | sched: Make pushable_tasks CONFIG_SMP dependant (diff) | |
| download | kernel-qcow2-linux-40dc11ffb35e8c4e8fa71092048e0f8de9db758c.tar.gz kernel-qcow2-linux-40dc11ffb35e8c4e8fa71092048e0f8de9db758c.tar.xz kernel-qcow2-linux-40dc11ffb35e8c4e8fa71092048e0f8de9db758c.zip | |
printk: Use this_cpu_{read|write} api on printk_pending
__get_cpu_var() is a bit inefficient, lets use __this_cpu_read() and
__this_cpu_write() to manipulate printk_pending.
printk_needs_cpu(cpu) is called only for the current cpu :
Use faster __this_cpu_read().
Remove the redundant unlikely on (cpu_is_offline(cpu)) test:
# size kernel/printk.o*
text data bss dec hex filename
9942 756 263488 274186 42f0a kernel/printk.o.new
9990 756 263488 274234 42f3a kernel/printk.o.old
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1290788536.2855.237.camel@edumazet-laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/printk.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/printk.c b/kernel/printk.c index a23315dc4498..ab3ffc5b3b64 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -1074,17 +1074,17 @@ static DEFINE_PER_CPU(int, printk_pending); void printk_tick(void) { - if (__get_cpu_var(printk_pending)) { - __get_cpu_var(printk_pending) = 0; + if (__this_cpu_read(printk_pending)) { + __this_cpu_write(printk_pending, 0); wake_up_interruptible(&log_wait); } } int printk_needs_cpu(int cpu) { - if (unlikely(cpu_is_offline(cpu))) + if (cpu_is_offline(cpu)) printk_tick(); - return per_cpu(printk_pending, cpu); + return __this_cpu_read(printk_pending); } void wake_up_klogd(void) |