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 32414EA812A for ; Tue, 10 Feb 2026 15:07:05 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 966056B008C; Tue, 10 Feb 2026 10:07:04 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 933FA6B0092; Tue, 10 Feb 2026 10:07:04 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 853666B0093; Tue, 10 Feb 2026 10:07:04 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 74B996B008C for ; Tue, 10 Feb 2026 10:07:04 -0500 (EST) Received: from smtpin16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 04FC41B3806 for ; Tue, 10 Feb 2026 15:07:03 +0000 (UTC) X-FDA: 84428874768.16.7CACA62 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf06.hostedemail.com (Postfix) with ESMTP id 26815180009 for ; Tue, 10 Feb 2026 15:07:01 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=none; spf=pass (imf06.hostedemail.com: domain of catalin.marinas@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=catalin.marinas@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1770736022; 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; bh=sOFu981r064UEV4nZdYzmU+/xsnUioQlrTOeHah7SXY=; b=1iaZDCMM0TpYW6hoAy4M4R96CR6vPiPfIGiDmXKI8QHh70YxeqKIfamUp5QtKuAYPPuIYl FMkEw7qGppKas+bI0ep9mQHLsiN5s+RaLBgjdMPK46Ty3vWsNTtlKKHANoPo+9qA+3v2y3 Tmammbk4YiAC2VtKBl13oYItbvTZf0Q= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1770736022; a=rsa-sha256; cv=none; b=rnXoUVZb5jR1TrsN+FzurCa+5n98YT09Fg0KYZ4uNbyaxL6fXA13CK50FSQ72LoK+MdMnU MXMcCDJ7llJQ9dpm1C0X2baosvv+h3QH2yz14BAAQ4tx7RfckwHbw6v2ioPfmqP2J1yypF cUtExu+HjHGtKhik7Itf3q5xWXUkV7g= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=none; spf=pass (imf06.hostedemail.com: domain of catalin.marinas@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=catalin.marinas@arm.com; dmarc=pass (policy=none) header.from=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 83A22150C; Tue, 10 Feb 2026 07:06:54 -0800 (PST) Received: from arm.com (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B054A3F63F; Tue, 10 Feb 2026 07:06:53 -0800 (PST) Date: Tue, 10 Feb 2026 15:06:51 +0000 From: Catalin Marinas To: Mike Rapoport Cc: Andrew Morton , Andreas Larsson , Borislav Petkov , Brian Cain , "Christophe Leroy (CS GROUP)" , "David S. Miller" , Dave Hansen , David Hildenbrand , Dinh Nguyen , Geert Uytterhoeven , Guo Ren , Helge Deller , Huacai Chen , Ingo Molnar , Johannes Berg , John Paul Adrian Glaubitz , "Liam R. Howlett" , Lorenzo Stoakes , Madhavan Srinivasan , Magnus Lindholm , Matt Turner , Max Filippov , Michael Ellerman , Michal Hocko , Michal Simek , Palmer Dabbelt , Richard Weinberger , Russell King , Stafford Horne , Suren Baghdasaryan , Thomas Gleixner , Vineet Gupta , Vlastimil Babka , Will Deacon , linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, loongarch@lists.linux.dev, linux-m68k@lists.linux-m68k.org, linux-openrisc@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org Subject: Re: [PATCH v2 4/4] mm: cache struct page for empty_zero_page and return it from ZERO_PAGE() Message-ID: References: <20260209144058.2092871-1-rppt@kernel.org> <20260209144058.2092871-5-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260209144058.2092871-5-rppt@kernel.org> X-Rspamd-Queue-Id: 26815180009 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: ug11ytk5jso653rt4aryk6ujuxrmsuss X-HE-Tag: 1770736021-702447 X-HE-Meta: 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 qL5CBeX+ h1zKktN/VmJfFoSiE25T/ulpO85tDpbauN0AWQ5yY1KGZoXgdj7TgsKQsk+z92ebes9KYtpi2vuEHK0oM/vRzo8l6F5XorNydhLMuO9ntQm6+6ocu7VNvEDEESvCXohxyENgDuTugIA41eUZJxv6nkhBpnshq7mz1yTuTL6SsT6Zpv08SGcBzEf+gO1jky0/rp0z+2IPwepj7QyoNt9o+vqgHf/STdmlLP/iDfr7di5gJdOEePrzXcD7kSciOvGPd9WYM50qLLMCbCF4= 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, Feb 09, 2026 at 04:40:57PM +0200, Mike Rapoport wrote: > From: "Mike Rapoport (Microsoft)" > > For most architectures every invocation of ZERO_PAGE() does > virt_to_page(empty_zero_page). But empty_zero_page is in BSS and it is > enough to get its struct page once at initialization time and then use > it whenever a zero page should be accessed. > > Add yet another __zero_page variable that will be initialized as > virt_to_page(empty_zero_page) for most architectures in a weak > arch_setup_zero_pages() function. > > For architectures that use colored zero pages (MIPS and s390) rename their > setup_zero_pages() to arch_setup_zero_pages() and make it global rather > than static. > > For architectures that cannot use virt_to_page() for BSS (arm64 and > sparc64) add override of arch_setup_zero_pages(). > > Signed-off-by: Mike Rapoport (Microsoft) For arm64: Acked-by: Catalin Marinas