From patchwork Thu May 31 09:58:17 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Beulich X-Patchwork-Id: 162130 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 3DC03B6FB9 for ; Thu, 31 May 2012 19:58:46 +1000 (EST) Received: from localhost ([::1]:41962 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Sa29T-0006yk-IP for incoming@patchwork.ozlabs.org; Thu, 31 May 2012 05:58:43 -0400 Received: from eggs.gnu.org ([208.118.235.92]:35887) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Sa29I-0006yR-0S for qemu-devel@nongnu.org; Thu, 31 May 2012 05:58:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Sa299-0004Qi-EF for qemu-devel@nongnu.org; Thu, 31 May 2012 05:58:31 -0400 Received: from nat28.tlf.novell.com ([130.57.49.28]:57704) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Sa299-0004QL-4K for qemu-devel@nongnu.org; Thu, 31 May 2012 05:58:23 -0400 Received: from EMEA1-MTA by nat28.tlf.novell.com with Novell_GroupWise; Thu, 31 May 2012 10:58:18 +0100 Message-Id: <4FC75CD902000078000871F6@nat28.tlf.novell.com> X-Mailer: Novell GroupWise Internet Agent 12.0.0 Date: Thu, 31 May 2012 10:58:17 +0100 From: "Jan Beulich" To: "xen-devel" , Mime-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) X-Received-From: 130.57.49.28 Cc: Stefano Stabellini Subject: [Qemu-devel] [PATCH, v2] qemu/xendisk: set maximum number of grants to be used X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Legacy (non-pvops) gntdev drivers may require this to be done when the number of grants intended to be used simultaneously exceeds a certain driver specific default limit. Change in v2: Double the number requested, as we need to account for the allocations needing to happen in contiguous chunks. The worst case number would be max_req * max_seg + (max_req - 1) * (max_seg - 1) + 1, but in order to keep things simple just use 2 * max_req * max_seg. Signed-off-by: Jan Beulich qemu/xendisk: set maximum number of grants to be used Legacy (non-pvops) gntdev drivers may require this to be done when the number of grants intended to be used simultaneously exceeds a certain driver specific default limit. Change in v2: Double the number requested, as we need to account for the allocations needing to happen in contiguous chunks. The worst case number would be max_req * max_seg + (max_req - 1) * (max_seg - 1) + 1, but in order to keep things simple just use 2 * max_req * max_seg. Signed-off-by: Jan Beulich --- a/hw/xen_disk.c +++ b/hw/xen_disk.c @@ -548,6 +548,11 @@ static void blk_alloc(struct XenDevice * if (xen_mode != XEN_EMULATE) { batch_maps = 1; } + if (xc_gnttab_set_max_grants(xendev->gnttabdev, + 2 * max_requests * BLKIF_MAX_SEGMENTS_PER_REQUEST) < 0) { + xen_be_printf(xendev, 0, "xc_gnttab_set_max_grants failed: %s\n", + strerror(errno)); + } } static int blk_init(struct XenDevice *xendev) --- a/hw/xen_disk.c +++ b/hw/xen_disk.c @@ -548,6 +548,11 @@ static void blk_alloc(struct XenDevice * if (xen_mode != XEN_EMULATE) { batch_maps = 1; } + if (xc_gnttab_set_max_grants(xendev->gnttabdev, + 2 * max_requests * BLKIF_MAX_SEGMENTS_PER_REQUEST) < 0) { + xen_be_printf(xendev, 0, "xc_gnttab_set_max_grants failed: %s\n", + strerror(errno)); + } } static int blk_init(struct XenDevice *xendev)