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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 EA959C982C4 for ; Wed, 16 Sep 2026 02:01:41 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4hl2F01CgLz2xkr; Wed, 16 Sep 2026 12:01:40 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip="2600:3c04:e001:324:0:1991:8:25" ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1789524100; cv=none; b=nqEuBYSI9Dtekjic9ubttfVKqtq3uN95Qm5YGryXMofDJSf4OdkSfZlXG/m3bQuWD/01K8wIzznIECO6eQ950snynknYWZRWDxd3k1V4bD4jARI0gBP3AjH8KnB3K51zK1jO2lQP0Llri2ar3slZe+BdCS8q0DGOBgbgzCpT3ZV0BdXDLIWndK4q2d/+YKV+plqgB2f8LAA1jJNcF8eqIE8a6yyDmoMvFVcr8I16lIDbVWWhCuttKygSsC6mugUimguT/miB/qshwgPOKPx76zj30AIjLsinQ1WclFzdXVTIZmA/PxZl4IRSL+1Eow1qYukzlZselOSw9V6bfmRmSg== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1789524100; c=relaxed/relaxed; bh=Kq4nX0CZWZvbBl1ewxdrR8njTtxJd2HKKhLZ4yZoin4=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=d9EDGqMIifmlAW3CtzPF2gJD1oSC1HOyd169kZu9kKnw7CymmMkTDwuFcLYnpAYuQeMYgnjgWHgzh/kYJusEyPV1aleXI5kr5V0Rw9kR/b4NP3hrXO4BCbRifVpCiv+Uwzpkr3t1UPnMZI7MLy0U5fiVncdWzisVSwluR7umXTEygWJ2EtT6N/b06DxuOyfnm3UolQFICwO8HiWeC30bdWPxSGMGHtEIhgYobRa++QJJD10I5qZbCv937InucmL3u3hrN9rZPJta01V5uv7jOPcN8FPN+yjDLKoH/glhxMdMj2gLQsGQDbdB/iRJb2lIFgkXFYVNcMljYqJHPCFyYg== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org; dkim=pass (1024-bit key; unprotected) header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=HA4IrxR+; dkim-atps=neutral; spf=pass (client-ip=2600:3c04:e001:324:0:1991:8:25; helo=tor.source.kernel.org; envelope-from=akpm@linux-foundation.org; receiver=lists.ozlabs.org) smtp.mailfrom=linux-foundation.org Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=HA4IrxR+; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux-foundation.org (client-ip=2600:3c04:e001:324:0:1991:8:25; helo=tor.source.kernel.org; envelope-from=akpm@linux-foundation.org; receiver=lists.ozlabs.org) Received: from tor.source.kernel.org (tor.source.kernel.org [IPv6:2600:3c04:e001:324:0:1991:8:25]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4hl2Dy6nCCz2xWV for ; Wed, 16 Sep 2026 12:01:38 +1000 (AEST) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id CDE3560214; Wed, 16 Sep 2026 02:01:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E999D1F00893; Wed, 16 Sep 2026 02:01:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1789524094; bh=Kq4nX0CZWZvbBl1ewxdrR8njTtxJd2HKKhLZ4yZoin4=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=HA4IrxR+bH6KFYi5TWsVFFRj5NN/KsmXWn+L2rcKXslNm+h4O1+C0Mz1TX/mnbSd5 wNlo1vs7L/RwOu/p4JC+a32HO1/edlho+RmyG7M/c8w2xQw4dUW63KjVSNntMUP6xo zHIhd6HWzSLYzzfxhv0JalmDYIqgVcBuZA1Pa2/U= Date: Tue, 15 Sep 2026 19:01:31 -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. 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 v3 00/12] mm: make userland page table freeing RCU-safe Message-Id: <20260915190131.adee185f2ce04a8ec821489c@linux-foundation.org> In-Reply-To: <20260911-rcu-pagetable-freeing-v3-0-7b8c86103821@kernel.org> References: <20260911-rcu-pagetable-freeing-v3-0-7b8c86103821@kernel.org> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 11 Sep 2026 20:36:47 +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. Thanks, I've updated mm.git's mm-unstable branch to this version. > v3: > * Added Kiryl's tag to series (thanks! :) > * Corrected commit message, comment indentation in 11/12 as per Kiryl. > * Corrected 12/12 documentation as per Kiryl. Here's how v3 altered mm.git: Documentation/mm/process_addrs.rst | 4 ++-- include/asm-generic/tlb.h | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) --- a/Documentation/mm/process_addrs.rst~b +++ a/Documentation/mm/process_addrs.rst @@ -541,8 +541,8 @@ We establish basic locking rules when in after an RCU grace period has elapsed. However, any entry found must be revalidated after the page table lock is taken (such as the :c:func:`!pmd_same` recheck performed by :c:func:`!pte_offset_map_lock`) - before it is acted upon. Changing an entry always requires the page table - lock. + before it is acted upon. Changing an entry requires the page table + lock and one of the locks that excludes teardown (mmap or VMA lock). * Reads from and writes to page table entries must be *appropriately* atomic. See the section on atomicity below for details. * Populating previously empty entries requires that the mmap or VMA locks are --- a/include/asm-generic/tlb.h~b +++ a/include/asm-generic/tlb.h @@ -151,8 +151,8 @@ * Page directories (__p*_free_tlb()) are always freed via tlb_remove_table(), * after an RCU grace period (see mm/mmu_gather.c). * - * This serialises against software page-table walkers, including architectures - * which do not use IPIs for remote TLB invalidates. + * This serialises against software page-table walkers, including architectures + * which do not use IPIs for remote TLB invalidates. * * An architecture is expected to provide __tlb_remove_table() (see * HAVE_ARCH_TLB_REMOVE_TABLE) or use the generic __tlb_remove_table(), which _