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Re: [PATCH -tip v3 0/3] tracepoint: Add signal events
- From: Oleg Nesterov <oleg at redhat dot com>
- To: Ingo Molnar <mingo at elte dot hu>
- Cc: Masami Hiramatsu <mhiramat at redhat dot com>, lkml <linux-kernel at vger dot kernel dot org>, Roland McGrath <roland at redhat dot com>, Jason Baron <jbaron at redhat dot com>, systemtap <systemtap at sources dot redhat dot com>, DLE <dle-develop at lists dot sourceforge dot net>
- Date: Tue, 24 Nov 2009 22:22:47 +0100
- Subject: Re: [PATCH -tip v3 0/3] tracepoint: Add signal events
- References: <20091120213108.14708.97871.stgit@dhcp-100-2-132.bos.redhat.com> <20091123175740.GA15594@elte.hu>
On 11/23, Ingo Molnar wrote:
>
> * Masami Hiramatsu <mhiramat@redhat.com> 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.
Oleg.