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 6E2E4C79FB6 for ; Wed, 9 Sep 2026 11:25:17 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6FF946B008C; Wed, 9 Sep 2026 07:25:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6D0086B0095; Wed, 9 Sep 2026 07:25:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5BEAD6B0096; Wed, 9 Sep 2026 07:25:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 349B36B008C for ; Wed, 9 Sep 2026 07:25:16 -0400 (EDT) Received: from smtpin24.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 950A840197 for ; Wed, 9 Sep 2026 11:25:15 +0000 (UTC) X-FDA: 85193992590.24.119DF60 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf24.hostedemail.com (Postfix) with ESMTP id 197D8180005 for ; Wed, 9 Sep 2026 11:25:13 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=YCsVcikz; spf=pass (imf24.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1788953114; 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=inNJzZhlDskfV4tobMRa6NUvX+KktI2JxAaJsuypEcU=; b=iDj45f6PXrtv71Ws+G7+Rd01B6u4URj16LJY+0NipGBSCKSRLFLWqp1yPq3SLRVcJpjP2S 01zLageLWCwHsW/PpJIQrbF0LpimBqMsA95jhdjyCqEbm1qOJz2k8VLvjtGOAboxROVdTB zq9l34f/ctNZRiRhmOe4WxJ7HiJDkSo= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=YCsVcikz; spf=pass (imf24.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1788953114; b=2NFw7J18lhsxXJDndkcDOomQ02jMEswm1utxDKFWavdFyHaPTwJa+lApiuI02DgU8cPZ+o 9LJzMFiLExhCPqy8gGADoxPwRCT7eHGJcNHjYh9D8oswOz4dkenVMolOMIeVK2DknUOW78 x23OitlT7igEgmuiCm/6ZEG7SgkLDbA= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 08BF160211; Wed, 9 Sep 2026 11:25:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA8571F00A3D; Wed, 9 Sep 2026 11:24:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788953112; bh=inNJzZhlDskfV4tobMRa6NUvX+KktI2JxAaJsuypEcU=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=YCsVcikzxNnvBT0Y3c5qUMcZq6CnjiF9LAucMz9KUDz/X8rycnl20TJiMBuTV44C6 ciuJ5X0Mary0o+RdhTl8tWHSISMo1lGTn+IXwhIQfs7dZg1NC//UvrgDFVVFH2BXXg wGSvIxQ/NBgeVTkoO77PEhxG5tF/kt0hk770YdbvA7jzYldeFCi6gaAA3Ie47dGZ4o rDioSU8ROD/U0Ex4wV585kl0B6XRkVhfL48+PBTUa/l0vXguhxnOvt9I9np0ualYy6 L7k5zESC+bnaJX5hWbMNkzgmSv0XEtgXO0Eiy5hQl/cIt/eJwNjq2z/FZB7YFfjxHL 0pO6lgM9ge/7g== Date: Wed, 9 Sep 2026 12:24:48 +0100 From: "Lorenzo Stoakes (ARM)" To: Andrew Morton Cc: David Hildenbrand , Zi Yan , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Kiryl Shutsemau , Guo Ren , Brian Cain , Geert Uytterhoeven , Dinh Nguyen , Simon Schuster , Jonas Bonn , Stefan Kristiansson , Stafford Horne , Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Russell King , Vineet Gupta , Michal Simek , Chris Zankel , Max Filippov , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Peter Zijlstra , "David S. Miller" , Andreas Larsson , Richard Henderson , Matt Turner , Magnus Lindholm , Catalin Marinas , Mark Rutland , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , "James E.J. Bottomley" , Helge Deller , Madhavan Srinivasan , Michael Ellerman , "Christophe Leroy (CS GROUP)" , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Richard Weinberger , Anton Ivanov , Johannes Berg , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Arnd Bergmann , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jason Gunthorpe , John Hubbard , Peter Xu , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-openrisc@vger.kernel.org, linux-sh@vger.kernel.org, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-snps-arc@lists.infradead.org, linux-arch@vger.kernel.org, sparclinux@vger.kernel.org, linux-alpha@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-um@lists.infradead.org, Hugh Dickins , Qi Zheng Subject: Re: [PATCH v2 00/12] mm: make userland page table freeing RCU-safe Message-ID: References: <20260908-rcu-pagetable-freeing-v2-0-1f60b64e878e@kernel.org> <20260908141543.8180b60400d38b70d249949b@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260908141543.8180b60400d38b70d249949b@linux-foundation.org> X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 197D8180005 X-Stat-Signature: w78st86win74zmuqa1bx8phgqibjzemj X-Rspam-User: X-HE-Tag: 1788953113-671233 X-HE-Meta: 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 TalpFoQb iX+ZRzfKRZXAPOZwft5nsHbvfRiu9k/t3rPXEKUma0F+9iKGO/iGUyhJUH3Kr3wOn4kvCjKk92QXG6UseKixIQ0Lif1RjYo1NWJxaBhr38SNvP25pODjKmIGMkyOIEOENErkx6Mhp6PbrWCMMlCqVWN5sXp3BtOxW8QgtG7zRO9C0PM8pwUkTcZLL7bZQet0ZQJ97N9vRAjmwyqnyRrwMLImaLAZrl5RJ9l2uxW80hdCYWLmR0pVc3EuvG+FIlLkC9kSkZtrfKzxKkM3N9CA6weiuxcUT0BzJkZa1g71SLM3CwO1of1sp/TzfE+ZeXcISmGYgb/P0/l05QIhWi6HgWPotoFNOACNFzClG Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Sep 08, 2026 at 02:15:43PM -0700, Andrew Morton wrote: > On Tue, 08 Sep 2026 13:32:09 +0100 "Lorenzo Stoakes (ARM)" wrote: > > > The majority of architectures in the kernel defer page table freeing until > > an RCU grace period has elapsed, this series converts all remaining > > architectures to do so too and eliminates CONFIG_MMU_GATHER_RCU_TABLE_FREE > > altogether. > > > > This is important because it enables safe lockless page table walking under > > RCU alone. > > > > Doing so allows for reduced lock contention, avoids lock ordering concerns > > and enables fast, efficient and correct page table walking as a result. > > > > Additionally it removes a bunch of code and architecture-specific behaviour > > which is always a beneficial thing to do. > > Thanks. It's early and unreviewed, but this is mainly an > if-it-compiles-its-good thing, so I'll add it for exposure to the > build/checker universe. Yeah largely, and I have done additional testing for cases which need it. > > > However some arches required extra attention - sh-X2, m68k-motorola and > > sparc32. > > OK. Please lmk later if you think additional reviewer/tester attention > is desirable in these areas. Only really the fancier sparc32 setup which can't be emulated [there's a call out in the cover for that one!] :) though sashiko found an issue with that that is now fixed. The other two I boot tested locally under emulation with no issues :) > -- Cheers, Lorenzo