From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MGYEE-0004ob-EL for qemu-devel@nongnu.org; Tue, 16 Jun 2009 08:57:30 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MGYE9-0004nA-MD for qemu-devel@nongnu.org; Tue, 16 Jun 2009 08:57:29 -0400 Received: from [199.232.76.173] (port=60042 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MGYE9-0004mw-9z for qemu-devel@nongnu.org; Tue, 16 Jun 2009 08:57:25 -0400 Received: from e5.ny.us.ibm.com ([32.97.182.145]:54647) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1MGYE8-0005oK-LF for qemu-devel@nongnu.org; Tue, 16 Jun 2009 08:57:24 -0400 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e5.ny.us.ibm.com (8.13.1/8.13.1) with ESMTP id n5GCpFJw025046 for ; Tue, 16 Jun 2009 08:51:15 -0400 Received: from d01av03.pok.ibm.com (d01av03.pok.ibm.com [9.56.224.217]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n5GCvNmZ254046 for ; Tue, 16 Jun 2009 08:57:23 -0400 Received: from d01av03.pok.ibm.com (loopback [127.0.0.1]) by d01av03.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n5GCvNUS025565 for ; Tue, 16 Jun 2009 08:57:23 -0400 Message-ID: <4A3796B1.8060003@us.ibm.com> Date: Tue, 16 Jun 2009 07:57:21 -0500 From: Anthony Liguori MIME-Version: 1.0 References: <4A36B025.2080602@us.ibm.com> <4A37618E.6040606@redhat.com> <4A379504.4080100@us.ibm.com> <4A3795F4.9080507@redhat.com> In-Reply-To: <4A3795F4.9080507@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: Live migration broken when under heavy IO List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: "qemu-devel@nongnu.org" , kvm-devel Avi Kivity wrote: > Yes, that's even better (though without linux-aio, it's equivalent). Not absolutely equivalent. There many be queued requests that haven't yet been dispatched to the thread pool, but yeah, I understand what you mean. >> >> The tricky bit is that this has to happen at the device layer because >> the opaques cannot be saved in a meaningful way. >> > > Do you mean the device has to record all cancelled requests and replay > them? I think we can do it at the block layer (though we have to > avoid it for nested requests). In order to complete the requests, you have to call a callback and pass an opaque with the results. The callback/opaque cannot be saved in the block layer in a meaningful way. -- Regards, Anthony Liguori