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From: Roland McGrath <roland@redhat.com>
To: Oleg Nesterov <oleg@redhat.com>
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Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>,
        Michael Holzheu <holzheu@linux.vnet.ibm.com>,
        Shailabh Nagar <nagar1234@in.ibm.com>,
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        Venkatesh Pallipadi <venki@google.com>,
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        Balbir Singh <balbir@linux.vnet.ibm.com>, Ingo Molnar <mingo@elte.hu>,
        Heiko Carstens <heiko.carstens@de.ibm.com>, linux-s390@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH 09/10] taskstats: Fix exit CPU time accounting
In-Reply-To: Oleg Nesterov's message of  Monday, 27 September 2010 18:51:33 +0200 <20100927165133.GA23535@redhat.com>
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Emacs: don't try this at home, kids!
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Date: Wed, 29 Sep 2010 12:19:16 -0700 (PDT)
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> > I would consider it to be a BUG() that the time is not accounted.
> > Independent of the fact that a parent wants to see the SIGCHLD and
> > the exit status of its child the process time of the child should be
> > accounted, no?
> 
> I do not know. It doesn't look like a BUG(), I mean it looks as if
> the code was intentionally written this way.

POSIX specifies this behavior: "If the child is never waited for (for
example, if the parent has SA_NOCLDWAIT set or sets SIGCHLD to SIG_IGN),
the resource information for the child process is discarded and not
included in the resource information provided by getrusage()."


Thanks,
Roland