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ftrace/x86: Have function graph tracer use its own trampoline 

The function graph trampoline is called from the function trampoline
and both do a save and restore of registers. The save of registers
done by the function trampoline when only the function graph tracer
is running is a waste of CPU cycles.

As the function graph tracer trampoline in x86 is dependent from
the function trampoline, we can call it directly when a function
is only being traced by the function graph trampoline.

Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Red Hat) 2014-07-11 23:23:53 -04:00 committed by Steven Rostedt
parent 646d7043ad
commit 1026ff9b8e
1 changed files with 2 additions and 0 deletions
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2
arch/x86/include/asm/ftrace.h
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@ -68,6 +68,8 @@ struct dyn_arch_ftrace {
int ftrace_int3_handler(struct pt_regs *regs);
#define FTRACE_GRAPH_TRAMP_ADDR FTRACE_GRAPH_ADDR
#endif /* CONFIG_DYNAMIC_FTRACE */
#endif /* __ASSEMBLY__ */
#endif /* CONFIG_FUNCTION_TRACER */