From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34934) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cVdMS-0000AB-LM for qemu-devel@nongnu.org; Mon, 23 Jan 2017 07:04:37 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cVdMN-0001re-Pj for qemu-devel@nongnu.org; Mon, 23 Jan 2017 07:04:36 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39768) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cVdMN-0001rN-Ku for qemu-devel@nongnu.org; Mon, 23 Jan 2017 07:04:31 -0500 Message-ID: <1485173068.2149.20.camel@redhat.com> From: Gerd Hoffmann Date: Mon, 23 Jan 2017 13:04:28 +0100 In-Reply-To: References: <20170118160332.13390-1-marcandre.lureau@redhat.com> <20170118160332.13390-24-marcandre.lureau@redhat.com> <1484814026.15364.15.camel@redhat.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH v2 23/25] console: make screendump async List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?ISO-8859-1?Q?Marc-Andr=E9?= Lureau Cc: qemu-devel@nongnu.org, armbru@redhat.com Hi, >=20 > If you only ref, you could have the image being modified while it is > being saved asynchronously, this could result in tearing artefacts, > no? Yes, but you have that problem _anyway_. screendump qmp command can run in parallel to guest vcpu, so it can race with guest display updates today. Assuming they happen as simple framebuffer writes and therefore don't involve vmexit + grabbing big qemu lock. cheers, Gerd