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| author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2019-11-08 19:12:57 +0100 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2019-11-13 15:36:49 +0100 |
| commit | a3ad1a7e39689005cb04a4f2adb82f9d55b4724f (patch) | |
| tree | 64deafb73e244d233836735dd2fa6a3c41462cc6 /arch/x86/kernel | |
| parent | ftrace/x86: Add register_ftrace_direct() for custom trampolines (diff) | |
| download | linux-a3ad1a7e39689005cb04a4f2adb82f9d55b4724f.tar.xz linux-a3ad1a7e39689005cb04a4f2adb82f9d55b4724f.zip | |
ftrace/x86: Add a counter to test function_graph with direct
As testing for direct calls from the function graph tracer adds a little
overhead (which is a lot when tracing every function), add a counter that
can be used to test if function_graph tracer needs to test for a direct
caller or not.
It would have been nicer if we could use a static branch, but the static
branch logic fails when used within the function graph tracer trampoline.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/ftrace.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index fef283f6341d..060a361d9d11 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -1049,9 +1049,11 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent, * return address is actually off by one word, and we * need to adjust for that. */ - if (ftrace_find_direct_func(self_addr + MCOUNT_INSN_SIZE)) { - self_addr = *parent; - parent++; + if (ftrace_direct_func_count) { + if (ftrace_find_direct_func(self_addr + MCOUNT_INSN_SIZE)) { + self_addr = *parent; + parent++; + } } /* |