Messages in this thread | | | Date | Mon, 20 Mar 2017 09:02:17 -0500 | From | Josh Poimboeuf <> | Subject | Re: [PATCH 5/6 v3] ftrace/x86_32: Add -mfentry support to x86_32 with DYNAMIC_FTRACE set |
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On Sat, Mar 18, 2017 at 05:09:28PM -0400, Steven Rostedt wrote: > From: "Steven Rostedt (VMware)" <rostedt@goodmis.org> > > x86_64 has had fentry support for some time. I did not add support to x86_32 > as I was unsure if it will be used much in the future. It is still very much > used, and there's issues with function graph tracing with gcc playing around > with the mcount frames, causing function graph to panic. The fentry code > does not have this issue, and is able to cope as there is no frame to mess > up. > > Note, this only add support for fentry when DYNAMIC_FTRACE is set. There's > really no reason to not have that set, because the performance of the > machine drops significantly when it's not enabled. I only keep > !DYNAMIC_FTRACE around to test it off, as there's still some archs that have > FTRACE but not DYNAMIC_FTRACE. > > Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> > Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
-- Josh
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