From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39049) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vkto9-0002Fr-Ns for qemu-devel@nongnu.org; Mon, 25 Nov 2013 05:54:31 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Vkto3-0008LN-L4 for qemu-devel@nongnu.org; Mon, 25 Nov 2013 05:54:25 -0500 Received: from mx1.redhat.com ([209.132.183.28]:34997) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vkto3-0008L5-6k for qemu-devel@nongnu.org; Mon, 25 Nov 2013 05:54:19 -0500 Message-ID: <52932C52.9080808@redhat.com> Date: Mon, 25 Nov 2013 11:54:10 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1380728469-29435-1-git-send-email-pl@kamp.de> <524C3FCE.4090908@redhat.com> <20131008123315.GE25109@dhcp-200-207.str.redhat.com> <5253FC11.3010309@redhat.com> <20131008123908.GG25109@dhcp-200-207.str.redhat.com> <52932ACF.6090104@kamp.de> In-Reply-To: <52932ACF.6090104@kamp.de> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] block/iscsi: introduce bdrv_co_{readv, writev, flush_to_disk} List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Lieven Cc: Kevin Wolf , ronniesahlberg@gmail.com, qemu-devel@nongnu.org, stefanha@redhat.com Il 25/11/2013 11:47, Peter Lieven ha scritto: > On 08.10.2013 14:39, Kevin Wolf wrote: >> Am 08.10.2013 um 14:35 hat Paolo Bonzini geschrieben: >>> Il 08/10/2013 14:33, Kevin Wolf ha scritto: >>>>>>>> this converts read, write and flush functions from aio to >>>>>>>> coroutines. >>>>>> I'm not sure it's already the time for this... Cancellation sucks in >>>>>> QEMU, and this is going to make things even worse. >>>> Not sure what you're referring to. If you mean iscsi_aio_cancel(), >>>> isn't >>>> it dead code anyway since we changed block.c to use coroutines for >>>> everything? bdrv_co_io_em() even throws the acb away, so even if you >>>> wanted, there's no way to cancel the request even today. >>> SCSI tries to use cancellation, and this results in VCPU threads >>> starving all other threads. So I would like to introduce cancellation >>> points for coroutines. >> Sounds like a nice thing to have, but it's unrelated to this patch. >> Cancellation means waiting for request completion before and after the >> patch. > > Can we proceed with the above patch for 1.8? Yes, thanks. Paolo