Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751844AbdF1Ptk (ORCPT ); Wed, 28 Jun 2017 11:49:40 -0400 Received: from smtp.eu.citrix.com ([185.25.65.24]:43025 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751515AbdF1Ptf (ORCPT ); Wed, 28 Jun 2017 11:49:35 -0400 X-IronPort-AV: E=Sophos;i="5.40,276,1496102400"; d="scan'208";a="48539508" Date: Wed, 28 Jun 2017 16:34:10 +0100 From: Roger Pau =?iso-8859-1?Q?Monn=E9?= To: Dongli Zhang CC: , , , , Subject: Re: [PATCH v2 1/1] xen/blkfront: always allocate grants first from per-queue persistent grants Message-ID: <20170628153410.replhtna2tpaxbrw@dhcp-3-128.uk.xensource.com> References: <1498654648-9970-1-git-send-email-dongli.zhang@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1498654648-9970-1-git-send-email-dongli.zhang@oracle.com> User-Agent: NeoMutt/20170609 (1.8.3) X-ClientProxiedBy: AMSPEX02CAS01.citrite.net (10.69.22.112) To AMSPEX02CL02.citrite.net (10.69.22.126) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 663 Lines: 15 On Wed, Jun 28, 2017 at 08:57:28PM +0800, Dongli Zhang wrote: > This patch partially reverts 3df0e50 ("xen/blkfront: pseudo support for > multi hardware queues/rings"). The xen-blkfront queue/ring might hang due > to grants allocation failure in the situation when gnttab_free_head is > almost empty while many persistent grants are reserved for this queue/ring. > > As persistent grants management was per-queue since 73716df ("xen/blkfront: > make persistent grants pool per-queue"), we should always allocate from > persistent grants first. > > Signed-off-by: Dongli Zhang Acked-by: Roger Pau Monn? Thanks.