Messages in this thread | | | Date | Tue, 24 Nov 2009 16:15:05 -0500 | From | Masami Hiramatsu <> | Subject | Re: [PATCH -tip v5 03/10] kprobes: Introduce kprobes jump optimization |
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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@redhat.com
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