Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934705Ab0KQMOf (ORCPT ); Wed, 17 Nov 2010 07:14:35 -0500 Received: from hera.kernel.org ([140.211.167.34]:38613 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934118Ab0KQMOe (ORCPT ); Wed, 17 Nov 2010 07:14:34 -0500 Message-ID: <4CE3C6A7.1060508@kernel.org> Date: Wed, 17 Nov 2010 13:12:23 +0100 From: Tejun Heo User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.9.2.12) Gecko/20101027 Lightning/1.0b2 Thunderbird/3.1.6 MIME-Version: 1.0 To: Kapil Arya CC: Gene Cooperman , Oren Laadan , ksummit-2010-discuss@lists.linux-foundation.org, linux-kernel@vger.kernel.org, hch@lst.de Subject: Re: [Ksummit-2010-discuss] checkpoint-restart: naked patch References: <4CD08419.5050803@kernel.org> <4CD26948.7050009@kernel.org> <20101104164401.GC10656@sundance.ccs.neu.edu> <4CD3CE29.2010105@kernel.org> <4CE3B23D.6040603@kernel.org> In-Reply-To: <4CE3B23D.6040603@kernel.org> X-Enigmail-Version: 1.1.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Wed, 17 Nov 2010 12:12:25 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1099 Lines: 25 On 11/17/2010 11:45 AM, Tejun Heo wrote: >> Since /proc/*/net provides a simpler design for sockets, we started >> wondering what other simplifications may be possible. Here is one >> possibility, in the case of shared file descriptors, DMTCP goes >> through two barriers in order to decide which process will be >> responsible for checkpointing which shared-file descriptor. It works >> and the overhead is reasonable, but if you have additional >> suggestion for this case, we would be very interested. > > I wrote in another mail but you can find out which fd's are shared by > flipping O_NONBLOCK and looking at the flags field of > /proc/*/fdinfo/*. Or are you talking about something else? Ooh, one more thing, /proc/*/net/* has tx/rx queue counts. With those, you wouldn't need the cookie based connection draining, right? Thanks. -- tejun -- 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/