From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_NEOMUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C4D69C28D18 for ; Wed, 5 Jun 2019 16:22:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9F37420866 for ; Wed, 5 Jun 2019 16:22:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728632AbfFEQWJ (ORCPT ); Wed, 5 Jun 2019 12:22:09 -0400 Received: from mx2.suse.de ([195.135.220.15]:58560 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726670AbfFEQWI (ORCPT ); Wed, 5 Jun 2019 12:22:08 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 537BDAD81; Wed, 5 Jun 2019 16:22:07 +0000 (UTC) Date: Wed, 5 Jun 2019 11:22:04 -0500 From: Goldwyn Rodrigues To: Dan Williams Cc: Matthew Wilcox , Jerome Glisse , Michal Hocko , lsf-pc@lists.linux-foundation.org, linux-xfs , linux-fsdevel , linux-ext4 , Linux Kernel Mailing List , linux-nvdimm Subject: Re: [Lsf-pc] [LSF/MM TOPIC] The end of the DAX experiment Message-ID: <20190605162204.jzou5hry5exly5wx@fiona> References: <20190214134622.GG4525@dhcp22.suse.cz> <20190214191013.GA3420@redhat.com> <20190214200840.GB12668@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716 Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Hi Dan/Jerome, On 12:20 14/02, Dan Williams wrote: > On Thu, Feb 14, 2019 at 12:09 PM Matthew Wilcox wrote: > > > > On Thu, Feb 14, 2019 at 11:31:24AM -0800, Dan Williams wrote: > > > On Thu, Feb 14, 2019 at 11:10 AM Jerome Glisse wrote: > > > > I am just again working on my struct page mapping patchset as well as > > > > the generic page write protection that sits on top. I hope to be able > > > > to post the v2 in couple weeks. You can always look at my posting last > > > > year to see more details. > > > > > > Yes, I have that in mind as one of the contenders. However, it's not > > > clear to me that its a suitable fit for filesystem-reflink. Others > > > have floated the 'page proxy' idea, so it would be good to discuss the > > > merits of the general approaches. > > > > ... and my preferred option of putting pfn entries in the page cache. > > Another option to include the discussion. > > > Or is that what you meant by "page proxy"? > > Page proxy would be an object that a filesystem could allocate to > point back to a single physical 'struct page *'. The proxy would > contain an override for page->index. Was there any outcome on this and its implementation? I am specifically interested in this for DAX support on btrfs/CoW: The TODO comment on top of dax_associate_entry() :) If there are patches/git tree I could use to base my patches on, it would be nice. -- Goldwyn