Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760071AbXJXOdy (ORCPT ); Wed, 24 Oct 2007 10:33:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758767AbXJXOc5 (ORCPT ); Wed, 24 Oct 2007 10:32:57 -0400 Received: from mo10.iij4u.or.jp ([210.138.174.78]:51036 "EHLO mo10.iij4u.or.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758324AbXJXOcx (ORCPT ); Wed, 24 Oct 2007 10:32:53 -0400 Date: Wed, 24 Oct 2007 23:32:11 +0900 To: jeff@garzik.org Cc: tomof@acm.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, James.Bottomley@SteelEye.com, jens.axboe@oracle.com, greg@kroah.com, muli@il.ibm.com, paulus@samba.org, tony.luck@intel.com, davem@davemloft.net, kyle@parisc-linux.org, aacraid@adaptec.com, fujita.tomonori@lab.ntt.co.jp Subject: Re: [PATCH -mm 0/11] fix iommu sg merging problem From: FUJITA Tomonori In-Reply-To: <471F2F42.1080806@garzik.org> References: <67bb10d9f4e9473ddc84d9839114602c1966f19f.tomof@acm.org> <471F2F42.1080806@garzik.org> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: <20071024233419K.tomof@acm.org> X-Dispatcher: imput version 20050308(IM148) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1924 Lines: 40 On Wed, 24 Oct 2007 07:40:50 -0400 Jeff Garzik wrote: > FUJITA Tomonori wrote: > > IOMMUs merges scatter/gather segments without considering a low level > > driver's restrictions. The problem is that IOMMUs can't access to the > > limitations because they are in request_queue. > > > > This patchset introduces a new structure, device_dma_parameters, > > including dma information. A pointer to device_dma_parameters is added > > to struct device. The bus specific structures (like pci_dev) includes > > device_dma_parameters. Low level drivers can use dma_set_max_seg_size > > to tell IOMMUs about the restrictions. > > > > We can move more dma stuff in struct device (like dma_mask) to struct > > device_dma_parameters later (needs some cleanups before that). > > > > This includes patches for all the IOMMUs that could merge sg (x86_64, > > ppc, IA64, alpha, sparc64, and parisc) though only the ppc patch was > > tested. The patches for other IOMMUs are only compile tested. > > > > Thanks to everyone for the comments on the previous submission > > to linux-scsi. > > > > This is against 2.6.24-rc1. The same patchset is also available: > > > > git://git.kernel.org/pub/scm/linux/kernel/git/tomo/linux-2.6-misc.git iommu-sg-fixes > > Are you interested in collecting patches to libata that eliminate the > hand-rolled S/G splitting? e.g. now ata_fill_sg() and mv_fill_sg() can > be made much more efficient. Yeah, but ATA has the segment boundary limit too. It's much more tricky than the segment size limit. It makes the IOMMU free space managemet complicated. > Again, thanks for doing this! It's been needed for a long time. My pleasure. - 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/