Re: [PATCH -tip v5 03/10] kprobes: Introduce kprobes jump optimization

[Masami Hiramatsu]

Frederic Weisbecker wrote:
> On Tue, Nov 24, 2009 at 10:34:08AM -0500, Masami Hiramatsu wrote:
> > > And this comment doesn't tell us much what this brings us.
> > > The changelog tells it stands to avoid a text_mutex deadlock.
> > > I'm not sure why we would deadlock without it.
> >
> > As Mathieu and I discussed on LKML (http://lkml.org/lkml/2009/11/21/187)
> > text_mutex will be locked on the way of cpu-hotplug.
> > Since kprobes locks text_mutex too and stop_machine() refers online_cpus,
> > it will cause a dead-lock. So, I decided to use get_online_cpus() to
> > locking hotplug while optimizing/unoptimizng.
>
>
> Ah ok :)
> Could you add a comment in the code that explains it?

Sure, of course :-)


--
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@xxxxxxxxxx

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