From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d12nrmr1607.megacenter.de.ibm.com (d12nrmr1607.megacenter.de.ibm.com [9.149.167.49]) by mtagate7.de.ibm.com (8.13.8/8.13.8) with ESMTP id m9H6ijhn314724 for ; Fri, 17 Oct 2008 06:44:45 GMT Received: from d12av03.megacenter.de.ibm.com (d12av03.megacenter.de.ibm.com [9.149.165.213]) by d12nrmr1607.megacenter.de.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id m9H6ijAd3281150 for ; Fri, 17 Oct 2008 08:44:45 +0200 Received: from d12av03.megacenter.de.ibm.com (loopback [127.0.0.1]) by d12av03.megacenter.de.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m9H6iimP015338 for ; Fri, 17 Oct 2008 08:44:45 +0200 Message-ID: <48F83458.2080602@fr.ibm.com> Date: Fri, 17 Oct 2008 08:44:40 +0200 From: Cedric Le Goater MIME-Version: 1.0 Subject: Re: [RFC v6][PATCH 0/9] Kernel based checkpoint/restart References: <1223461197-11513-1-git-send-email-orenl@cs.columbia.edu> <20081009124658.GE2952@elte.hu> <1223557122.11830.14.camel@nimitz> <20081009131701.GA21112@elte.hu> <1223559246.11830.23.camel@nimitz> <20081009134415.GA12135@elte.hu> <1223571036.11830.32.camel@nimitz> <20081010153951.GD28977@elte.hu> <48F30315.1070909@fr.ibm.com> <1223916223.29877.14.camel@nimitz> <48F6092D.6050400@fr.ibm.com> <48F685A3.1060804@cs.columbia.edu> <48F7352F.3020700@fr.ibm.com> <48F74674.20202@cs.columbia.edu> <87r66g8875.wl%peter@chubb.wattle.id.au> In-Reply-To: <87r66g8875.wl%peter@chubb.wattle.id.au> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Peter Chubb Cc: Oren Laadan , Daniel Lezcano , jeremy@goop.org, arnd@arndb.de, containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Dave Hansen , linux-mm@kvack.org, Alexander Viro , "H. Peter Anvin" , Ingo Molnar , Thomas Gleixner , Andrey Mirkin List-ID: > Oren> For now, yes. But we definitely want this capability in the long > Oren> run; otherwise we won't be able to checkpoint a kernel compile > Oren> ('make' uses vfork), or anything with 'gdb' running inside, or > Oren> 'strace', and other goodies. > > The strace/gdb example is *really* hard; but for vfork, you just wait > until it's over. The interval between vfork and exec/exit should be > short enough not to affect the overall time for a checkpoint (and > checkpoint can be fairly slow anyway --- on the HPC machines we used > to do it on, writing half a terabyte of checkpoint image to disc could take > many minutes. In hindsight, we should have multithreaded it). we've tried that and it doesn't change a thing if you have only one disk :) it might even give worse results as you are increasing context switches. > Waiting for a vforked process to exec is less than a millisecond. yes that shouldn't be too hard to handle. Cheers, C. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org