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authorEric Dumazet <eric.dumazet@gmail.com>2010-11-26 17:22:16 +0100
committerIngo Molnar <mingo@elte.hu>2010-12-08 20:16:01 +0100
commit40dc11ffb35e8c4e8fa71092048e0f8de9db758c (patch)
tree88ae143dab98b902b7ec94220160560463c063f9 /kernel/printk.c
parent806c09a7db457be3758e14b1f152761135d89af5 (diff)
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/printk.c')
-rw-r--r--kernel/printk.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/printk.c b/kernel/printk.c
index a23315dc449..ab3ffc5b3b6 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)