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

[Masami Hiramatsu <mhiramat@redhat.com>]

Oleg Nesterov wrote:
> 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.

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@redhat.com