Messages in this thread | | | Date | Mon, 18 Jan 2010 13:21:02 -0500 | From | Masami Hiramatsu <> | Subject | Re: [RFC PATCH 2/8] jump label v4 - x86: Introduce generic jump patching without stop_machine |
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Mathieu Desnoyers wrote: > * Arjan van de Ven (arjan@infradead.org) wrote: >> On Mon, 18 Jan 2010 10:59:30 -0500 >> Masami Hiramatsu <mhiramat@redhat.com> wrote: >> >>> Yeah, so in the latest patch, I updated it to use int3 even if >>> len == 1. :-) >>> >> >> >> int3 is not making a difference for your case; there is no guarantee >> that the other processor even sees the "int3 inbetween state" at all; >> if it's not safe without int3 then it won't be safe with int3 either. > > What Masami means is that he updated his patch to use the int3+IPI > broadcast scheme.
Right.
> > Therefore, the CPUs not seeing the int3 inbetween state will be forced > to issue a serializing instruction while the int3 is in place anyway.
By the way, in kprobes, we just use a text_poke() to put int3. I assume that we'd better send IPI afterward, wouldn't it?
Thank you,
-- Masami Hiramatsu
Software Engineer Hitachi Computer Products (America), Inc. Software Solutions Division
e-mail: mhiramat@redhat.com
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