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Message-ID: <4B01C95B.1070302@redhat.com>
Date: Mon, 16 Nov 2009 16:51:23 -0500
From: Masami Hiramatsu <mhiramat@...hat.com>
To: Ingo Molnar <mingo@...e.hu>
CC: Roland McGrath <roland@...hat.com>,
lkml <linux-kernel@...r.kernel.org>,
systemtap <systemtap@...rces.redhat.com>,
DLE <dle-develop@...ts.sourceforge.net>
Subject: Re: [PATCH -tip 3/3] Add get_signal tracepoint
Ingo Molnar wrote:
>> Especially if you call this "get" rather than "deliver", there is
>> another place that should invoke this tracepoint (or perhaps a third
>> one). sys_rt_sigtimedwait "gets" a signal without delivering it. In
>> POSIX terminology this is called "accepting" the signal: the three
>> things that can happen in the life of a signal are "generate",
>> "deliver", and "accept". If you are trying to match up what happened
>> to a signal generated by kill() or whatnot, then you want to notice
>> both delivery and acceptance as the complementary event.
>>
>> (And again I have no clue why this signal stuff should be called
>> "sched" at all.)
>
> it shouldnt be called 'sched' - it should go into 'events/signal.h'.
>
> But we also need fuller coverage than this. Coredumps and signal
> delivery events are just a small part of all things signals, we also
> want:
That's a good idea. I'll put coredump and signal related events
into events/signal.h.
>
> - signal generation events (send_sig*() variants)
Those events finally calls __send_signal(), so I think
trace_signal_send() can trace those events.
> - signal IPI/wakeup events
All signals might be used for IPI, isn't it? :-)
Or, did you mean SIGSTOP/SIGCONT pare?
> - signal loss events (queue overflow)
Perhaps, this event is only for rt-signals, since
legacy signals just overwritten if it was sent.
Thank you,
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division
e-mail: mhiramat@...hat.com
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