From: Shan Wei <davids...@tencent.com>
__this_cpu_inc_return() or __this_cpu_dec generates a single instruction,
which is faster than __get_cpu_var operation.
Signed-off-by: Shan Wei <davids...@tencent.com>
---
kernel/trace/trace.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 18c0aa8..3795694 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1313,7 +1313,7 @@ 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
@@ -1367,7 +1367,7 @@ 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();
}
--
1.7.1
--
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