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authorMinho Ban <mhban@samsung.com>2012-05-07 11:36:00 +0900
committerSteven Rostedt <rostedt@goodmis.org>2012-05-08 09:33:52 -0400
commitb02ee9a33b65bcc4ad13c12a0b04afdaab3ddd8d (patch)
treebf634618536dd15ffb8d0129efeb7aac312279c6
parent19631cb3d67c24c8b1fa58bc69bc2fed8d15095d (diff)
downloadop-kernel-dev-b02ee9a33b65bcc4ad13c12a0b04afdaab3ddd8d.zip
op-kernel-dev-b02ee9a33b65bcc4ad13c12a0b04afdaab3ddd8d.tar.gz
tracing: Prevent wasting time evaluating parameters in trace_preempt_on/off
This fixes spending time for evaluating parameters in trace_preempt_on/off when the tracer config is off. The patch mainly inspired by Steven Rostedt, thanks Steven. Link: http://lkml.kernel.org/r/4FA73510.7070705@samsung.com Cc: Ingo Molnar <mingo@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Turner <pjt@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Minho Ban <mhban@samsung.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
-rw-r--r--include/linux/ftrace.h8
1 files changed, 6 insertions, 2 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 0b55903..d32cc5e 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -491,8 +491,12 @@ static inline void __ftrace_enabled_restore(int enabled)
extern void trace_preempt_on(unsigned long a0, unsigned long a1);
extern void trace_preempt_off(unsigned long a0, unsigned long a1);
#else
- static inline void trace_preempt_on(unsigned long a0, unsigned long a1) { }
- static inline void trace_preempt_off(unsigned long a0, unsigned long a1) { }
+/*
+ * Use defines instead of static inlines because some arches will make code out
+ * of the CALLER_ADDR, when we really want these to be a real nop.
+ */
+# define trace_preempt_on(a0, a1) do { } while (0)
+# define trace_preempt_off(a0, a1) do { } while (0)
#endif
#ifdef CONFIG_FTRACE_MCOUNT_RECORD
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