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From: "Mattias Engdegård" <f91-men@nada.kth.se>
To: pmenage@ensim.com
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH][RFC] Pollable /proc/<pid>/ - avoid SIGCHLD/poll() races
Date: Fri, 5 Oct 2001 11:36:28 +0200 (MET DST)	[thread overview]
Message-ID: <200110050936.LAA14156@my.nada.kth.se> (raw)
In-Reply-To: <E15pFHM-0002H1-00@pmenage-dt.ensim.com> (message from Paul Menage on Thu, 04 Oct 2001 13:39:36 -0700)
In-Reply-To: <E15pFHM-0002H1-00@pmenage-dt.ensim.com>

Paul Menage <pmenage@ensim.com> wrote:
>Except that this enhancement is not completely safe, as if you get more
>than 1024 children reaped (assuming you send two bytes of pid and two
>bytes of status) between checks of the pipe, you'll lose notifications.

Obviously, but the cases where the number of children is bounded below
1024 are rather frequent

>At least if you're only using the pipe to stop select() from blocking,
>you don't care about overflowing the pipe as there's no important
>information in there anyway.

sure, but then you have to put the pid/exit status somewhere else and
do some signal blocking/unblocking. In either case, it's portable,
which polling on /proc/pid isn't


  reply	other threads:[~2001-10-05  9:36 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-10-04  7:52 Paul Menage
2001-10-04  8:59 ` Christoph Rohland
2001-10-04  9:31   ` Paul Menage
2001-10-04 10:25     ` Christoph Rohland
2001-10-13 15:44     ` Jamie Lokier
2001-10-04 14:18 ` Mattias Engdegård
2001-10-04 20:39   ` Paul Menage
2001-10-05  9:36     ` Mattias Engdegård [this message]
2001-10-13 15:36   ` Jamie Lokier
2001-10-14  2:25     ` John Alvord

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