From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Serge E. Hallyn" Subject: Re: [patch 100/148] cgroups: convert tasks file to use a seq_file with shared pid array Date: Wed, 17 Jun 2009 08:52:16 -0500 Message-ID: <20090617135216.GC18056@us.ibm.com> References: <200810190328.m9J3S4aB000311@imap1.linux-foundation.org> <6599ad830906162146n5a79b9b8n3b7dd0e72c72ab7@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <6599ad830906162146n5a79b9b8n3b7dd0e72c72ab7-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Paul Menage Cc: akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, Linux Containers List-Id: containers.vger.kernel.org Quoting Paul Menage (menage-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org): > It just struck me that this patch broke access to the tasks file in > the presence of multiple pid namespaces, since the pids in the cached Hmm, sure does. > pid array are always from the namespace of the last process to open > the file. Well it's only around as long as the file is open, so I guess that's another reason noone has hit this bug. A task in pidns B must open the file between the open and close by a task in pidns A. > Since I suspect no-one uses pid namespaces in production > environments this probably isn't a show-stopper, but to be technically > correct we need to maintain a list of cached pid arrays keyed by pid > namespace. (This list should generally be very short, usually of > length 1). Just to clarify - do you have a patch in the works for this, or are you asking for the patch to be written? thanks, -serge