Re: [PATCH -tip v3 0/3] tracepoint: Add signal events

[Masami Hiramatsu]

Oleg Nesterov wrote:
> On 11/23, Ingo Molnar wrote:
> > * Masami Hiramatsu<mhiramat@xxxxxxxxxx>  wrote:
> >
> > > Hi,
> > >
> > > These patches add signal related tracepoints including
> > > signal generation, delivery, and loss. First patch also
> > > moves signal-sending tracepoint from events/sched.h to
> > > events/signal.h.
> > >
> > > Changes in v3
> > > - Add Docbook style comments
> > >
> > > Changes in v2
> > > - Add siginfo arguments
> > >
> > > Thank you,
> > >
> > > ---
> > >
> > > Masami Hiramatsu (3):
> > >        tracepoint: Add signal loss events
> > >        tracepoint: Add signal deliver event
> > >        tracepoint: Move signal sending tracepoint to events/signal.h
> > >
> > >
> > >   Documentation/DocBook/tracepoint.tmpl |    5 +
> > >   include/trace/events/sched.h          |   25 -----
> > >   include/trace/events/signal.h         |  173 +++++++++++++++++++++++++++++++++
> > >   kernel/signal.c                       |   27 ++++-
> > >   4 files changed, 198 insertions(+), 32 deletions(-)
> > >   create mode 100644 include/trace/events/signal.h
> >
> > Would be nice to have Roland's and Oleg's Acked-by tags in the patches -
> > to show that this is a representative and useful looking set of signal
> > events.
>
> Sorry, I can't really comment these patches.
>
> I mean, I do not know which info is useful and which is not.
> For example, I am a bit surprized we report trace_signal_lose_info()
> but please do not consider this as if I think we shouldn't. Just I
> do not know.
>
> OTOH, we do not report if __send_signal() fails just because the
> legacy signal is already queued. We do not report who sends the signal,
> we do not report if it was private or shared. zap_process, complete_signal
> can "send" SIGKILL via sigaddset, this won't be noticed. But again, it is
> not that I think this should be reported.
>
> In short: I think any info may be useful, and these patches can help.
> But I do not understand what exactly should be reported to userspace.

Yeah, any comments are welcome:-) IMHO, these tracepoints are just for
providing options for users who care about who sent the signal, etc.

Thank you,

--
Masami Hiramatsu

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

e-mail: mhiramat@xxxxxxxxxx

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