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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 39852CCF9E3 for ; Tue, 11 Nov 2025 00:17:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2797A8E0008; Mon, 10 Nov 2025 19:17:52 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 251468E0003; Mon, 10 Nov 2025 19:17:52 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 167488E0008; Mon, 10 Nov 2025 19:17:52 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 06B838E0003 for ; Mon, 10 Nov 2025 19:17:52 -0500 (EST) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id A3B02160315 for ; Tue, 11 Nov 2025 00:17:51 +0000 (UTC) X-FDA: 84096413142.28.155E639 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf06.hostedemail.com (Postfix) with ESMTP id E674218000F for ; Tue, 11 Nov 2025 00:17:49 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=vjkeLHDm; spf=pass (imf06.hostedemail.com: domain of akpm@linux-foundation.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1762820270; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=VRa6a9PTVAKzZIPhPoFYhNCRojY7+kwf6ee46naNTlw=; b=hBvrnc7sg6lSf5xlVD5YflWQjmZdxZq1lnvy2Wgt4FwN8A2mfDUwjysqpGdRcyf0tjIk7q UKbqqfzgDBWS+6vrc9IG7gDR4Svr5HSlW6nJeRd/kfJlWtl5hEN90b9BAN/X7AF/BoojC2 CLzX2edFUV0hlkw/JntSrJ+ykPEcFNo= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=vjkeLHDm; spf=pass (imf06.hostedemail.com: domain of akpm@linux-foundation.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1762820270; a=rsa-sha256; cv=none; b=OyWqOxuRzAHxskfJtDqUQ+D8JvS+kLdXY4shPxgce2m5DuH+rSgV3wrIdoOSO23jwASm9g iGHswvUayyvDNfeGw6CzlwyPgUwgGdDbqgTUhyElbcTbA9Qtmg2rXDarXaGxyQf/3kxtRd KBJVmA3y2CsoqlDDYf4C69c6wIUcPbU= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 1776560195; Tue, 11 Nov 2025 00:17:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 68CB5C4CEFB; Tue, 11 Nov 2025 00:17:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1762820268; bh=h4IOFDJ10o8gxsjF+0swXOnDNA//+lvIGav3YD5mbm4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=vjkeLHDmhlbRmdh2J8YEkuADTnOje8197r13F9Y+9M4PNEGyrIjTsJrXa9FcWBd30 3dmWPQqBvqXKMpha7c0qNKjQ5ewY10+fA5vTYMX7SAz0x9GQP2DAUfOdVKd+b+ILms w4QnZBmAPYCsSnhcOO+V0J4HJESA9uFYopLe6MVY= Date: Mon, 10 Nov 2025 16:17:45 -0800 From: Andrew Morton To: Lorenzo Stoakes Cc: Christian Borntraeger , Janosch Frank , Claudio Imbrenda , David Hildenbrand , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Sven Schnelle , Peter Xu , Alexander Viro , Christian Brauner , Jan Kara , Arnd Bergmann , Zi Yan , Baolin Wang , "Liam R . Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Muchun Song , Oscar Salvador , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Axel Rasmussen , Yuanchu Xie , Wei Xu , Kemeng Shi , Kairui Song , Nhat Pham , Baoquan He , Chris Li , SeongJae Park , Matthew Wilcox , Jason Gunthorpe , Leon Romanovsky , Xu Xin , Chengming Zhou , Jann Horn , Miaohe Lin , Naoya Horiguchi , Pedro Falcato , Pasha Tatashin , Rik van Riel , Harry Yoo , Hugh Dickins , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-s390@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, damon@lists.linux.dev Subject: Re: [PATCH v2 00/16] mm: remove is_swap_[pte, pmd]() + non-swap entries, introduce leaf entries Message-Id: <20251110161745.2075f263e3c693bf65f98ccc@linux-foundation.org> In-Reply-To: References: X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: E674218000F X-Stat-Signature: fr3ny8qr8t6djgyutift56drnb5qkxma X-Rspam-User: X-HE-Tag: 1762820269-557263 X-HE-Meta: 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 n2KCOgHE UABHZQw6X6ki/4xBElbi+iW2+2boJu0+TJjJZOIxrty0GlqFZE/EuMsXZ8TuVJ5sGa/a8UUadVdgzUE9fxDRygBQq/EZEJ1iWeKcd4m4qtEKGn5D0sVAkoZ35DBxuP3riCf3+MIsFxNlMkQFvHGqQbKgmJIoVF5E196uuqijVD3cS6JC8C9uC8eBvO8m8pqNGzJY229GNIfLeIVTCnTOGp/lddIKhLdKkT6dgZuUUOjhUnIOK7CmMNiTfxMSCyF/PMyfZBRXfT6x5vUI9HO/R9pM2OcGGu8uibIBXPoQ2ok+1ijyU3ivldl20J7ux4/5pCjrRameQCT+eU3KKDGJAsvOCW4cFVMYlMqejc0whTjnYmM9JsFpi/Gh264ahjjedFed+lC8+Iy8YcEI= 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: List-Subscribe: List-Unsubscribe: On Mon, 10 Nov 2025 22:21:18 +0000 Lorenzo Stoakes wrote: > There's an established convention in the kernel that we treat leaf page > tables (so far at the PTE, PMD level) as containing 'swap entries' should > they be neither empty (i.e. p**_none() evaluating true) nor present > (i.e. p**_present() evaluating true). > > However, at the same time we also have helper predicates - is_swap_pte(), > is_swap_pmd() - which are inconsistently used. > > This is problematic, as it is logical to assume that should somebody wish > to operate upon a page table swap entry they should first check to see if > it is in fact one. > > It also implies that perhaps, in future, we might introduce a non-present, > none page table entry that is not a swap entry. > > This series resolves this issue by systematically eliminating all use of > the is_swap_pte() and is swap_pmd() predicates so we retain only the > convention that should a leaf page table entry be neither none nor present > it is a swap entry. Thanks, I updated mm.git's mm-unstable branch to this version the patchset.