From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:38283) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RgH57-0001dq-Db for qemu-devel@nongnu.org; Thu, 29 Dec 2011 09:35:46 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RgH56-000638-07 for qemu-devel@nongnu.org; Thu, 29 Dec 2011 09:35:45 -0500 Received: from mx1.redhat.com ([209.132.183.28]:24498) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RgH55-000633-NK for qemu-devel@nongnu.org; Thu, 29 Dec 2011 09:35:43 -0500 Message-ID: <4EFC7AB8.807@redhat.com> Date: Thu, 29 Dec 2011 16:35:36 +0200 From: Avi Kivity MIME-Version: 1.0 References: <4EFC4DF0.2040708@redhat.com> <20111229123922.GG19274@valinux.co.jp> <4EFC634E.10406@redhat.com> <20111229134920.GH19274@valinux.co.jp> <4EFC70BA.1080808@redhat.com> <20111229141802.GI19274@valinux.co.jp> In-Reply-To: <20111229141802.GI19274@valinux.co.jp> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 0/2][RFC] postcopy migration: Linux char device for postcopy List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Isaku Yamahata Cc: Andrea Arcangeli , t.hirofuchi@aist.go.jp, qemu-devel@nongnu.org, kvm@vger.kernel.org, satoshi.itoh@aist.go.jp On 12/29/2011 04:18 PM, Isaku Yamahata wrote: > > > > > > The issue is how to solve the page fault, not whether TASK_INTERRUPTIBLE or > > > TASK_UNINTERRUPTIBLE. > > > I can think of several options. > > > - When daemon X is dead, all page faults are served by zero pages. > > > - When daemon X is dead, all page faults are resovled as VM_FAULT_SIGBUS > > > - list/reattach: complications. You don't like it > > > - other? > > > > Don't resolve the page fault. It's up to the user/system to make sure > > it happens. qemu can easily do it by watching for the daemon's death > > and respawning it. > > > > When the new daemon is started, it can ask the kernel for a list of > > pending requests, and service them. > > Great, then we agreed with list/reattach basically. > (Maybe identity scheme needs reconsideration.) I guess we miscommunicated. Why is reattach needed? If you have the fd, nothing else is needed. -- error compiling committee.c: too many arguments to function