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SubjectRe: [PATCH v2 0/6] ftrace: to kill a daemon (small updates)

* Steven Rostedt <rostedt@goodmis.org> wrote:

> [
> Changes since v1:
>
> regex fix in x86_64 recordmcount.pl. Now it can handle all
> mcount+0x... mcount-0x... and mcount, where as the original
> only handled mcount+0x...
>
> Made mcount on start-up to simply return. The current mcount
> is set up to be replaced with a call to ftrace_record_ip.
> This is no longer necessary.
>
> Note: This patch series is focusing on how calls to mcount in
> the kernel are converted to nops. It does not address what
> kind of nop is used. That is a different topic, and should
> be in a different patch series.
>
> Note 2: I have found that the changes here are more stable than
> the current daemon method, and these patches should be used.
> It also solves the resume from suspend to ram bug that was
> reported:
>
> http://lkml.org/lkml/2008/8/12/234
> and
> http://lkml.org/lkml/2008/8/12/451
>
> Note 3: I have already ported this to PowerPC64, but I am waiting
> for this to be accepted first before submitting those changes.
> ]
>
> One of the things that bothered me about the latest ftrace code was
> this annoying daemon that would wake up once a second to see if it had
> work to do. If it did not, it would go to sleep, otherwise it would do
> its work and then go to sleep.

i like this concept alot - i've applied the whole lot to
tip/tracing/ftrace.

Eventually gcc should be extended to provide a separate section for
instrumentation patch sites, instead of us having to disassemble the
object code. That would also make the ftrace build faster. Any gcc folks
interested in that?

Ingo


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