Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761480AbYBGBi1 (ORCPT ); Wed, 6 Feb 2008 20:38:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753951AbYBGBiT (ORCPT ); Wed, 6 Feb 2008 20:38:19 -0500 Received: from tama50.ecl.ntt.co.jp ([129.60.39.147]:34085 "EHLO tama50.ecl.ntt.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752900AbYBGBiS (ORCPT ); Wed, 6 Feb 2008 20:38:18 -0500 To: davem@davemloft.net Cc: fujita.tomonori@lab.ntt.co.jp, tomof@acm.org, jens.axboe@oracle.com, linux-kernel@vger.kernel.org Subject: Re: more iommu sg merging fallout From: FUJITA Tomonori In-Reply-To: <20080206.160147.25411834.davem@davemloft.net> References: <20080206.151855.136436571.davem@davemloft.net> <20080207085333Q.fujita.tomonori@lab.ntt.co.jp> <20080206.160147.25411834.davem@davemloft.net> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: <20080207103801T.fujita.tomonori@lab.ntt.co.jp> Date: Thu, 07 Feb 2008 10:38:01 +0900 X-Dispatcher: imput version 20040704(IM147) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1768 Lines: 34 On Wed, 06 Feb 2008 16:01:47 -0800 (PST) David Miller wrote: > From: FUJITA Tomonori > Date: Thu, 07 Feb 2008 08:53:33 +0900 > > > On Wed, 06 Feb 2008 15:18:55 -0800 (PST) > > David Miller wrote: > > > > > I intend to put merging back in, perhaps something similar to > > > powerpc's merging logic but without the expensive (in my opinion) > > > IOMMU allocation every loop. I think it is better to determine the > > > segment breaks in one pass, allocate that many IOMMU entries in one > > > allocation, then fill them all in. > > > > I thought about asking you if I can modify the SPARC IOMMUs to do > > allocation in every loop. > > > > The reason why I need the allocation in every loop is that I also need > > to fix the problem that IOMMUs allocate memory areas without > > considering a low level driver's segment boundary limits. > > > > http://linux.derkeiler.com/Mailing-Lists/Kernel/2007-11/msg07616.html > > http://linux.derkeiler.com/Mailing-Lists/Kernel/2007-12/msg02286.html > > > > As far as I know, all the IOMMUs except for SPARC allocate a free area > > in every loop but if it's too expensive for SPARC, then we need to > > find a different way to handle segment boundary limits. > > Ok then what I'll do is adopt some version of powerpc's merging > allocator into the sparc64 code. Great, thanks! SPARC IOMMUs use bitmap for the free area management like POWER IOMMUs so it could use lib/iommu-helper as POWER does. -- 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/