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Message-ID: <a36005b50901071302q70160bady41abc5ed2b105474@mail.gmail.com>
Date: Wed, 7 Jan 2009 13:02:32 -0800
From: "Ulrich Drepper" <drepper@gmail.com>
To: "Roland McGrath" <roland@redhat.com>
Subject: Re: [RESEND][RFC PATCH v2] waitfd
Cc: "Ingo Molnar" <mingo@elte.hu>, "Casey Dahlin" <cdahlin@redhat.com>,
       "Linux Kernel" <linux-kernel@vger.kernel.org>,
       "Randy Dunlap" <randy.dunlap@oracle.com>,
       "Oleg Nesterov" <oleg@redhat.com>,
       "Davide Libenzi" <davidel@xmailserver.org>,
       "Peter Zijlstra" <a.p.zijlstra@chello.nl>
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References: <49639EB8.40204@redhat.com> <4963ABF0.6070400@redhat.com>
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On Wed, Jan 7, 2009 at 12:53 PM, Roland McGrath <roland@redhat.com> wrote:
> Do we really need another one for this?  How about using signalfd plus
> setting the child's exit_signal to a queuing (SIGRTMIN+n) signal instead of
> SIGCHLD?  It's slightly more magical for the userland process to know to do
> that (fork -> clone SIGRTMIN).  But compared to adding a syscall we don't
> really have to add, maybe better.

Since waitfd shouldn't consume the child termination notification
waitfd should be more widely usable than the wait*() interfaces.
I.e., it's not necessary to restrict the use to parents.  Any process
with the same UID should be allowed to call waitfd.  This would allow
some new user cases.
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