From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=41647 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Q0Xia-00053c-VU for qemu-devel@nongnu.org; Fri, 18 Mar 2011 07:19:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Q0XiZ-0007do-Jj for qemu-devel@nongnu.org; Fri, 18 Mar 2011 07:19:44 -0400 Received: from verein.lst.de ([213.95.11.211]:49843 helo=newverein.lst.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Q0XiZ-0007dF-Bm for qemu-devel@nongnu.org; Fri, 18 Mar 2011 07:19:43 -0400 Date: Fri, 18 Mar 2011 12:19:41 +0100 From: Christoph Hellwig Subject: Re: [Qemu-devel] [PATCH 6/6] ide: Avoid canceling IDE DMA Message-ID: <20110318111941.GA25520@lst.de> References: <1280846670-27063-1-git-send-email-kwolf@redhat.com> <1280846670-27063-7-git-send-email-kwolf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1280846670-27063-7-git-send-email-kwolf@redhat.com> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: qemu-devel@nongnu.org On Tue, Aug 03, 2010 at 04:44:30PM +0200, Kevin Wolf wrote: > Furthermore because the DMA operation is splitted into many synchronous > aio_read/write if there's more than one entry in the SG table, without this > patch the DMA would be cancelled in the middle, something we've no idea if it > happens on real hardware too or not. Overall this seems a great risk for zero > gain. That hasn't been true for a long time when this code was commited, at least on kernel supporting preadv/pwritev and/or aio.