From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id 4A3216B0260 for ; Mon, 9 Oct 2017 14:59:05 -0400 (EDT) Received: by mail-pf0-f197.google.com with SMTP id p87so8189435pfj.21 for ; Mon, 09 Oct 2017 11:59:05 -0700 (PDT) Received: from quartz.orcorp.ca (quartz.orcorp.ca. [184.70.90.242]) by mx.google.com with ESMTPS id g69si7544821ita.125.2017.10.09.11.59.04 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 09 Oct 2017 11:59:04 -0700 (PDT) Date: Mon, 9 Oct 2017 12:58:40 -0600 From: Jason Gunthorpe Subject: Re: [PATCH v7 07/12] dma-mapping: introduce dma_has_iommu() Message-ID: <20171009185840.GB15336@obsidianresearch.com> References: <150732931273.22363.8436792888326501071.stgit@dwillia2-desk3.amr.corp.intel.com> <150732935473.22363.1853399637339625023.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <150732935473.22363.1853399637339625023.stgit@dwillia2-desk3.amr.corp.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Dan Williams Cc: linux-nvdimm@lists.01.org, Jan Kara , Ashok Raj , "Darrick J. Wong" , linux-rdma@vger.kernel.org, Greg Kroah-Hartman , Joerg Roedel , Dave Chinner , linux-xfs@vger.kernel.org, linux-mm@kvack.org, Jeff Moyer , linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, Ross Zwisler , David Woodhouse , Robin Murphy , Christoph Hellwig , Marek Szyprowski On Fri, Oct 06, 2017 at 03:35:54PM -0700, Dan Williams wrote: > otherwise be quiesced. The need for this knowledge is driven by a need > to make RDMA transfers to DAX mappings safe. If the DAX file's block map > changes we need to be to reliably stop accesses to blocks that have been > freed or re-assigned to a new file. If RDMA is driving this need, why not invalidate backing RDMA MRs instead of requiring a IOMMU to do it? RDMA MR are finer grained and do not suffer from the re-use problem David W. brought up with IOVAs.. Jason -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org