Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965095AbWHOSpc (ORCPT ); Tue, 15 Aug 2006 14:45:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965114AbWHOSpc (ORCPT ); Tue, 15 Aug 2006 14:45:32 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:62671 "EHLO ebiederm.dsl.xmission.com") by vger.kernel.org with ESMTP id S965095AbWHOSpa (ORCPT ); Tue, 15 Aug 2006 14:45:30 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Alan Cox Cc: Andrew Morton , linux-kernel@vger.kernel.org, containers@lists.osdl.org, Oleg Nesterov Subject: Re: [PATCH 6/7] vt: Update spawnpid to be a struct pid_t References: <1155666193191-git-send-email-ebiederm@xmission.com> <1155667982.24077.307.camel@localhost.localdomain> Date: Tue, 15 Aug 2006 12:45:09 -0600 In-Reply-To: <1155667982.24077.307.camel@localhost.localdomain> (Alan Cox's message of "Tue, 15 Aug 2006 19:53:02 +0100") Message-ID: User-Agent: Gnus/5.110004 (No Gnus v0.4) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1244 Lines: 35 Alan Cox writes: > Ar Maw, 2006-08-15 am 12:23 -0600, ysgrifennodd Eric W. Biederman: >> This keeps the wrong process from being notified if the >> daemon to spawn a new console dies. > > Not sure why we count pids not task structs but within the proposed > implementation this appears correct so Basically struct pid is relatively cheap, 64bytes or so. struct task is expensive 10K or so, when all of the stacks and everything are included. Counting pids allows the task to exit in user space and free up all of it's memory. When /proc used to count the task struct it was fairly easy to deliberately oom a 32bit machine just by open up directories in /proc and then having the process exit. rlimits didn't help because we don't count processes that have exited. > > Acked-by: Alan Cox Thanks. When I get to the tty portion of this I think I am going to have to synchronize with you as last I looked you were working in this area as well. Eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/