From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:56816) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SDZ5R-0006j0-0B for qemu-devel@nongnu.org; Fri, 30 Mar 2012 06:29:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SDZ5M-0004Oe-EF for qemu-devel@nongnu.org; Fri, 30 Mar 2012 06:29:40 -0400 Received: from mail-lpp01m010-f45.google.com ([209.85.215.45]:49254) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SDZ5M-0004ON-3W for qemu-devel@nongnu.org; Fri, 30 Mar 2012 06:29:36 -0400 Received: by lahe6 with SMTP id e6so583147lah.4 for ; Fri, 30 Mar 2012 03:29:33 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1333097427-20912-1-git-send-email-zwu.kernel@gmail.com> References: <1333097427-20912-1-git-send-email-zwu.kernel@gmail.com> Date: Fri, 30 Mar 2012 11:29:33 +0100 Message-ID: From: Stefan Hajnoczi Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v3 2/2] block: disable I/O throttling on sync api List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: zwu.kernel@gmail.com Cc: kwolf@redhat.com, wuzhy@linux.vnet.ibm.com, qemu-devel@nongnu.org, stefanha@linux.vnet.ibm.com On Fri, Mar 30, 2012 at 9:50 AM, wrote: > + =A0 =A0 * When all sync I/O drivers are converted to async I/O, it will= be restored > + =A0 =A0 * to the original state. The problem here is that guess_disk_lchs() uses bdrv_read(), not whether device emulation uses sync or async I/O. Converting devices to async I/O will not fix this. Stefan