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authorShan Wei <davidshan@tencent.com>2012-11-19 13:21:01 +0800
committerSteven Rostedt <rostedt@goodmis.org>2013-01-25 20:36:54 -0500
commit821465295b36136998ef294fe176fba4e09c1cd9 (patch)
tree241bf19a408130332b123780b55fc8303fee491b
parentd75f717e19fe595e7efbf67de195ada8d89dfbbe (diff)
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 <cl@linux.com> Signed-off-by: Shan Wei <davidshan@tencent.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
-rw-r--r--kernel/trace/trace.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ca9b7dfed8ef..07888e15c694 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();
}