From: Shan Wei Date: Mon, 19 Nov 2012 05:21:01 +0000 (+0800) Subject: tracing: Use __this_cpu_inc/dec operation instead of __get_cpu_var X-Git-Tag: v3.9-rc1~173^2~10^2~8 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=821465295b36136998ef294fe176fba4e09c1cd9;p=platform%2Fkernel%2Flinux-exynos.git tracing: Use __this_cpu_inc/dec operation instead of __get_cpu_var __this_cpu_inc_return() or __this_cpu_dec generates a single instruction, which is faster than __get_cpu_var operation. Link: http://lkml.kernel.org/r/50A9C1BD.1060308@gmail.com Reviewed-by: Christoph Lameter Signed-off-by: Shan Wei Signed-off-by: Steven Rostedt --- diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index ca9b7df..07888e1 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1344,7 +1344,7 @@ static void __ftrace_trace_stack(struct ring_buffer *buffer, */ preempt_disable_notrace(); - use_stack = ++__get_cpu_var(ftrace_stack_reserve); + use_stack = __this_cpu_inc_return(ftrace_stack_reserve); /* * We don't need any atomic variables, just a barrier. * If an interrupt comes in, we don't care, because it would @@ -1398,7 +1398,7 @@ static void __ftrace_trace_stack(struct ring_buffer *buffer, out: /* Again, don't let gcc optimize things here */ barrier(); - __get_cpu_var(ftrace_stack_reserve)--; + __this_cpu_dec(ftrace_stack_reserve); preempt_enable_notrace(); }