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 611C3CCFA13 for ; Sat, 8 Nov 2025 18:01:11 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7B1C98E0006; Sat, 8 Nov 2025 13:01:10 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 761FE8E0003; Sat, 8 Nov 2025 13:01:10 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 651358E0006; Sat, 8 Nov 2025 13:01:10 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 4F8B98E0003 for ; Sat, 8 Nov 2025 13:01:10 -0500 (EST) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 08475140812 for ; Sat, 8 Nov 2025 18:01:10 +0000 (UTC) X-FDA: 84088206300.17.F53CE02 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf14.hostedemail.com (Postfix) with ESMTP id 3405E100015 for ; Sat, 8 Nov 2025 18:01:08 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=oDUv3HSn; spf=pass (imf14.hostedemail.com: domain of akpm@linux-foundation.org designates 172.234.252.31 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=1762624868; 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=GiBoPXBJufdX5B3STDLZ2n5iNuptKizgzFgu85Zt+VQ=; b=WF9hYSCua2yB0yKXHBRQW7nCgrMwJ+yCGoNtkxrXRjBZs0YJxu/m3Bly9tobmrTblPIDtC 0us7rP53qor/LX9A56KfwVzY/6PSnAFFiDVEb8UZ6lBj/G3lQEodo7T5r4vDQuwYRJTO6y pGIPFU2yEHBroPt6uP0A/N3OSyTtQmU= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=oDUv3HSn; spf=pass (imf14.hostedemail.com: domain of akpm@linux-foundation.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1762624868; a=rsa-sha256; cv=none; b=2XaqyEEfKveRAQ+VMsSb9e9ZQuE6YNAcGNDwc5jX699cAcKmdBgnpBrt2NZYo1sUza0VH9 L7mjvGuXo9CBwHGZyO5Jq2c8dlVC1CgZ7ld+/H25TYGMyCCfnLnZpB3JYB9N5NBxnUR3mY Ve3aIpDYoaCgEc9DVq8y0lzug0nSolQ= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id CDED6405B3; Sat, 8 Nov 2025 18:01:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9EDFDC4CEFB; Sat, 8 Nov 2025 18:01:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1762624866; bh=WY8ReV6b5rLneuyL9AKjyd/kw56HVWU1CULr7FLVHP4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=oDUv3HSnjIfwPyFkFpXgxuM9gpIrqWGxlj+VbGgMDqQY7mvSx4LjzbZNiu+GyW66l sBSmHMFXObgsrY/JwizQJcL8IlCvpaHLDnEETtyGW2/R+vrTgZKu9v3oCok35vTcqF jmex0BTITiOowYk1xFcmp3KlwKUu3Iwim/OcS0ek= Date: Sat, 8 Nov 2025 10:01:04 -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: <20251108100104.bb9fc75f97b9263af7e5673b@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: 3405E100015 X-Stat-Signature: j3wj7eq7xfk6xdk641sjqk5qbt9d5wcr X-Rspam-User: X-HE-Tag: 1762624868-34790 X-HE-Meta: U2FsdGVkX19FB1512VKK7QEoE/H7DeeUcuROrr9EHo1Pp77Wa/aM3yyeAY9umDw1IR+MqSKZPafvUzLUfflOGhc2sDoQPzzdD4qOhpsdvRvUUUpMQpOm+K+Llaw+wexSISVdZqdv2UiZhQNlEPGYML9K2Gksou2CHn5quK+LKHr5BnsJGwYKe+JGkYW8+bEp50LgmO8PyeSdX/jE4fNab5MLUIlraLPaL45kRUKqEQbqHpkqz2yEHCyhE9KkwNWKWwHUV31X/TOc8bjDlZK2S5PQYvXqG+ywMF9DXZWE/mS54+RYsmeL8+AG1mXtPpGSw8SIHMUpFx4bU30Yt/khxpgaylf/7REL43KIAzpzS2xrHF4aTFhUC0fBWtAU0xzs5UaPEAlBKSWKDL/w2rveUChRaFpd+nhipEZA2nC+G3pnLBfdJKir3nNjjeY2zQ/QW7YELuyMXePpwGzVWpjtCQmR+fotodZWVL6egKTjjXiqHGZ/pehnLHE1PcK9J11Zz7sci7zW4Uc8Gr+wh4aQhSTuM3mswrykiI6zuVloZWNjlM1jWmH3cxXlB0mAzFLNh+MAc4xOzEAWzFDOTXSNpBSgPctuDBthzqXVtr+mzisvqLR+LCAP84cMHusMxvb34inFjPtNmrmM8bfEYgvXuR6cSZgnK2NLzYX5OXmIg6dM2GQnKtXdRp471cbUKAp+jDKipHL3sLN21DuMu6jWS5XKJfzepDWlOJLDqhbdfwdUNqYWBV9ojh1FmqX9U8HrhRhgZBb2VIUhGqpKTmqUYbvZuFgi6qSFJNjbhpp2pUidFYnPxuIaP/2XRc5aUHIL6FQPynN3Aj4rwk4qh8ccDnyMs1wE18n0ybcCPrKSaFH3Z0wGt1f4huHW20mPriT+Ne0HM3MsZuUI3c6E6U2XuMFVs3JXHrmtQjwpZW9v3ElKDbamLSIY1IqGPYFa3bFWJud5BMsJje+Y4ycr8u/ cFbasacc SLu2V6IXagpp+Q4vlwMtymCBph8e8VqF23MDFEzsZr38WhrtEuFw69uSI/KgQkbHPYCFwxosJWQKQdUL9eu2mePNywTNPLIusUm/g/kVRXhjvLkdo32LIW7x14X+FdsI45qSMhDjUNIqlMNPzqjga2+/OebY3wALEte+Z2/+RAh4lwvTnd1eIOPqGdumdzNA1eaXAjST29WB/a4MF1a8rWYuE2BIj85d0YuPZ7YI2Vs5PtjqGnnYhL2UENesTjPYegsoGeR9XFkS12rkVQEIBc2Avh+7VHTra6yAB1fuPszxY8o8hF3I8n/TdHs+eAHoJ0jvCmo+ZbhrGUnp4Uk7AeDR21VL2LbPlhPPWeKtNh5skYY9rS4E8DvSwYHxzQ4ReHztpMGpGBNa4Eo0= 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 Sat, 8 Nov 2025 17:08:14 +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've updated mm.git's mm-unstable branch to this v2 series.