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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5AAE7C79FAA for ; Tue, 8 Sep 2026 21:15:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:Mime-Version:References:In-Reply-To:Message-Id:Subject:Cc:To: From:Date:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=eVg9GefJyoXHHA5a69mXqnQLyloUJ4YxIPGGpLvgyr0=; b=O2oWWxYSRjiODYhRoNamAWYxbW C4srKRISHmEwjORIaCi3rPGMiDykVTebm8UrhOFGCIa1MCyDVDwooQRY88NtirLha13hrHOM29AkC +LuwK6YdjDYwW3rTpYCr0ndZqo6/bBHFh2gBBVXOGTdq5EacHk7hBOeqKxXy7kdJLFGWzFwyBLsOK MZkrgHPVGoKBzvFxKZ6y2jIQHScU5oN+gPngZmkH3F/75CJgK5ffCku8qHLoyosS19J8ZQn7JEvHi eJAbEDVyYKCKVW95MLHvrVSMLOFNSrQr5/N+9cqaNrMG1lkmqMVdgG+uFwpt+Kwk2jtA1LKeqajye cBIKmVbw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x43AV-0000000AIe8-0o0A; Tue, 08 Sep 2026 21:15:51 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x43AS-0000000AIdP-3MHz; Tue, 08 Sep 2026 21:15:48 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 54B69601F9; Tue, 8 Sep 2026 21:15:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5E1EB1F00A3A; Tue, 8 Sep 2026 21:15:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1788902147; bh=eVg9GefJyoXHHA5a69mXqnQLyloUJ4YxIPGGpLvgyr0=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=S61FQutZ9GAkmusTuBm8tba1mRd5os9NdWI1OcYUdnUCilKfQqRFUpY9X0910S1CM WZ7yUO067yRvIkgkaa3uP271RNhAevtq90hMdQ5fuv0628aYooJ26Y2LotuEU39MiY QQuRFXCkF1Dzu+58mWFPPcGHJySDbzaovnewoTOY= Date: Tue, 8 Sep 2026 14:15:43 -0700 From: Andrew Morton To: "Lorenzo Stoakes (ARM)" 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. 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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: <20260908141543.8180b60400d38b70d249949b@linux-foundation.org> In-Reply-To: <20260908-rcu-pagetable-freeing-v2-0-1f60b64e878e@kernel.org> References: <20260908-rcu-pagetable-freeing-v2-0-1f60b64e878e@kernel.org> 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-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org 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. > 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.