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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7AF6ECAAA1 for ; Fri, 9 Sep 2022 18:11:57 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DE7FC8D0001; Fri, 9 Sep 2022 14:11:56 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D96D86B0072; Fri, 9 Sep 2022 14:11:56 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C5E078D0001; Fri, 9 Sep 2022 14:11:56 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id B40816B0071 for ; Fri, 9 Sep 2022 14:11:56 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 93C561A0229 for ; Fri, 9 Sep 2022 18:11:56 +0000 (UTC) X-FDA: 79893340632.19.7E62430 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf07.hostedemail.com (Postfix) with ESMTP id 4F2DA40074 for ; Fri, 9 Sep 2022 18:11:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=K3rEGQsv9BVwA6kFBpw+S4FQ+EQeuMIv7O7eLl5u0rw=; b=O8P9Ae9GbkjzsWNrdQYmIBdIur UCdi1Q9zOS9sdHX5NNA+sreQJVZFyJAjOs7cTmAMkP7Ff+zi1oMP6cwFjgcYLLFwIHmAbYDfQMewZ muwNZbY05oszhg5SZXH5W0fsmXZi4Em9YBK/0dS2xcUtmU4pU0NGjGL7hxYrJLAleUmHjCaz4NlI3 g09ArFO/JKgrQIpB67VyXiS6+3YOYxLHzS3NkQYaLA+N6SQVt17PEDxi9jQsi3EYdi/gKbQood8yq kEsAwAY8TkyIQ8tIpiEz3qKBeuHVImwXe3eGL7FNR+0t0lFMXR6UzXKUBRjxF40uw2SPO+jROZxsX v7feLepg==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1oWiTd-00DSSd-Fu; Fri, 09 Sep 2022 18:11:41 +0000 Date: Fri, 9 Sep 2022 19:11:41 +0100 From: Matthew Wilcox To: Dan Williams Cc: Jason Gunthorpe , akpm@linux-foundation.org, Jan Kara , Christoph Hellwig , "Darrick J. Wong" , John Hubbard , linux-mm@kvack.org, nvdimm@lists.linux.dev, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 00/13] Fix the DAX-gup mistake Message-ID: References: <6317a26d3e1ed_166f2946e@dwillia2-xfh.jf.intel.com.notmuch> <6317ebde620ec_166f29466@dwillia2-xfh.jf.intel.com.notmuch> <6318d07fa17e7_166f29495@dwillia2-xfh.jf.intel.com.notmuch> <6318e66861c87_166f294f1@dwillia2-xfh.jf.intel.com.notmuch> <631902ef5591a_166f2941c@dwillia2-xfh.jf.intel.com.notmuch> <631a420ad2f28_166f29423@dwillia2-xfh.jf.intel.com.notmuch> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <631a420ad2f28_166f29423@dwillia2-xfh.jf.intel.com.notmuch> ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1662747115; a=rsa-sha256; cv=none; b=x9JZHgABsCFynn6EYF7eO+MCRQHoWKpQYdnwOQgide7VyCbykCnZKRHPCD+AlirOzXvt0Z kcW72VCm/uztk2ftKsg0b7iflUgI9GTvA0Ze5/ezrU2rv5CNEvVwgBC21Cb/BWZ3EFIv0j ptrxmyoR3cPwIFXrumEOuEmWyqV52nI= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=O8P9Ae9G; spf=none (imf07.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1662747115; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=K3rEGQsv9BVwA6kFBpw+S4FQ+EQeuMIv7O7eLl5u0rw=; b=Ezxt7CjStVhQVSoj6L4KhIqb/WwrqFh8VUVBKCUGvI1rOrwK/3SJ1+MrcI6zbt4a30k5M0 UfRxBKQ3nDoHRvJznIfvVRQ0pjim8rfQ7tzTTzRDGJxzQrcnuSSOBoabtm7eUfJ1zBGUrf 9RWtWs8Vdvm6iCCYFn+FmRE7rLEZj+w= Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=O8P9Ae9G; spf=none (imf07.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none X-Rspam-User: X-Stat-Signature: acqpa1xdkrwm7cqrngum9q5oye977a9a X-Rspamd-Queue-Id: 4F2DA40074 X-Rspamd-Server: rspam08 X-HE-Tag: 1662747115-669009 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Sep 08, 2022 at 12:27:06PM -0700, Dan Williams wrote: > This thread is mainly about DAX slowly reinventing _mapcount that gets > managed in all the right places for a normal_page. Longer term I think > we either need to get back to the page-less DAX experiment and find a > way to unwind some of this page usage creep, or cut over to finally > making DAX-pages be normal pages and delete most of the special case > handling in fs/dax.c. I am open to discussing the former, but I think > the latter is more likely. I'm still very much in favour of the former. I've started on replacing scatterlist with phyr, but haven't got very far yet.