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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Ulrich Drepper <drepper@redhat.com>
Cc: Linux Kernel List <linux-kernel@vger.kernel.org>,
	Roland McGrath <roland@redhat.com>, Andrew Morton <akpm@osdl.org>
Subject: Re: [PATCH] bug in setpgid()? process groups and thread groups
Date: 02 Aug 2003 01:50:58 -0700	[thread overview]
Message-ID: <1059814257.18860.38.camel@ixodes.goop.org> (raw)
In-Reply-To: <3F2B7435.7070101@redhat.com>

On Sat, 2003-08-02 at 01:20, Ulrich Drepper wrote:
> Your approach with iterating over the threads is not acceptable (at
> least to me). 

I've noticed that postings with patches get paid a lot more attention to
those without.  It was just the patch I used to prove to myself what the
problem is.

> It is racy (concurrent runs are not synchronized) 

Erm, it's protected by tasklist_lock, so that isn't a problem.

> and has
> a non-constant time.  We've sketched out already a mechanism which
> solves to problem.  Basically, most of the time the value from the
> thread group leader is used (just follow the pointer).  Then setting the
> value is an atomic operation an constant.

I was considering that, but it needs changes all over the place where
people look at current->pgrp.  This way makes for a clearer patch.

	J


  reply	other threads:[~2003-08-02  8:51 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-08-02  7:57 [PATCH] bug in setpgid()? process groups and thread groups Jeremy Fitzhardinge
2003-08-02  8:20 ` Ulrich Drepper
2003-08-02  8:50   ` Jeremy Fitzhardinge [this message]
2003-08-02 19:08     ` Roland McGrath
2003-08-02 20:30       ` Nicholas Miell
2003-08-02 20:51       ` Alan Cox
2003-08-03  7:22         ` Florian Weimer
2003-08-03 21:00           ` Alan Cox
2003-08-03  4:15       ` Jeremy Fitzhardinge
2003-08-02 18:39   ` William Lee Irwin III

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