Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752869AbYJ0IVy (ORCPT ); Mon, 27 Oct 2008 04:21:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751739AbYJ0IVq (ORCPT ); Mon, 27 Oct 2008 04:21:46 -0400 Received: from gw.goop.org ([64.81.55.164]:40731 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751116AbYJ0IVq (ORCPT ); Mon, 27 Oct 2008 04:21:46 -0400 Message-ID: <49057A15.7030007@goop.org> Date: Mon, 27 Oct 2008 19:21:41 +1100 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.17 (X11/20081009) MIME-Version: 1.0 To: FUJITA Tomonori CC: linux-kernel@vger.kernel.org, mingo@elte.hu, jens.axboe@oracle.com Subject: Re: [PATCH 2/2] x86: replace BIO_VMERGE_BOUNDARY with BIOVEC_PHYS_MERGEABLE References: <20081024143836K.fujita.tomonori@lab.ntt.co.jp> <4902371A.5050303@goop.org> <20081027125139I.fujita.tomonori@lab.ntt.co.jp> In-Reply-To: <20081027125139I.fujita.tomonori@lab.ntt.co.jp> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 861 Lines: 21 FUJITA Tomonori wrote: > The block layer always done the physical merge if possible. We don't > provide any kernel parameter to disable it. > > The iommu_bio_merge parameter had been used to enable the virtual > merge. As I wrote, the virtual merge feature was completely > removed. Effectively, the iommu_bio_merge parameter is meaningless > now. > Under Xen, pages which appear to be pseudo-physically adjacent are not necessarily really physically adjacent. We need to hook BIOVEC_PHYS_MERGEABLE to prevent the bio layer from inappropriately merging requests across non-contiguous page boundaries. J -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/