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 B302CECD6E9 for ; Wed, 11 Feb 2026 20:14:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B6FD96B0005; Wed, 11 Feb 2026 15:14:35 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B308F6B0088; Wed, 11 Feb 2026 15:14:35 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A127D6B0089; Wed, 11 Feb 2026 15:14:35 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 921446B0005 for ; Wed, 11 Feb 2026 15:14:35 -0500 (EST) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 57E76C2061 for ; Wed, 11 Feb 2026 20:14:35 +0000 (UTC) X-FDA: 84433278510.18.F1EAC54 Received: from mail-ej1-f43.google.com (mail-ej1-f43.google.com [209.85.218.43]) by imf21.hostedemail.com (Postfix) with ESMTP id 3891F1C0007 for ; Wed, 11 Feb 2026 20:14:32 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=BE6CEEcb; spf=pass (imf21.hostedemail.com: domain of linmag7@gmail.com designates 209.85.218.43 as permitted sender) smtp.mailfrom=linmag7@gmail.com; dmarc=pass (policy=none) header.from=gmail.com; arc=pass ("google.com:s=arc-20240605:i=1") ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1770840873; 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=28hr9LjidhOb4+7vDtUZiT7dYr2nuAMqMlceW5mXuOg=; b=ZMIeGUFuoOxtKsa6Gg8EfGlnv9lPmZLqi9oZVwinJCypaD4ahUmOd02+0oj9LHcLE3mHYM cINw2CkRwyYqmyN8daW3YmFamSxr8VNRb47DYcYg/Lxm5CFQ7gZUJH7vVxki5Q8AnwaGI8 Rptq3rPFU2gTbVVw89T3+BeXj6o1Ym4= ARC-Authentication-Results: i=2; imf21.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=BE6CEEcb; spf=pass (imf21.hostedemail.com: domain of linmag7@gmail.com designates 209.85.218.43 as permitted sender) smtp.mailfrom=linmag7@gmail.com; dmarc=pass (policy=none) header.from=gmail.com; arc=pass ("google.com:s=arc-20240605:i=1") ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1770840873; a=rsa-sha256; cv=pass; b=Vn2o0gOrRvQ7FJlyGPzoEtMyURZcXFOQMbGyR9C52IJTwex3wKWqa9wKbMpob4RAlMRe4E jmSFO1D4lfHf0XB/+17ngXqUT0QeQ9JczSfZBuDVR1Hi4LUhvPeg2VFDLj+von2K9XT067 vJBMUUClU7AtE2ILQRx/Ph8NBFq5jPg= Received: by mail-ej1-f43.google.com with SMTP id a640c23a62f3a-b8871718b00so909109266b.3 for ; Wed, 11 Feb 2026 12:14:32 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1770840872; cv=none; d=google.com; s=arc-20240605; b=fSMXlQH1IFO5oY3cE2y9jAUEAukWPC1uXVKWPmPaBUXlmq4tS/ynfZuR/T1A/4+75m YcPkCNso+irLNBxj0jBwVekQO0y4layP8Mu/JRteajNgCigT3qT2piT4iGfVDb0gWt17 hfBN5kdZ7FtRSV4Xs6GNdkJalOct+0iM38rWkgfiQOS86sZgid02GBn1dHj1VKmgrzvK 9yEGRdzvYcA0IckEZfTcSo678YcSToSSAxJxTlcn6VPlkbfFuoUn6VLLBArjPdAXCx6S r9lUykL9sUOgrKkAs+dVz7WjslNES5m3AmWhELcUDlqPbqYMojEnIaR7q++T4WveK0FG EzkQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20240605; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:dkim-signature; bh=28hr9LjidhOb4+7vDtUZiT7dYr2nuAMqMlceW5mXuOg=; fh=VN+A5oAlPiPZmll4xcZJnc09MnRSbbjDv1N+BYaT/+k=; b=kVzKTQtiH3MkejxZPLjxYKm+4P5K8/sFBSp66mkI0IqgdeuhkPoRWp3GI7L4Y4koSy PwYO+JhoQyjCVlxCvHC+OjwOnsWhcXdn8te5bqMiXxpVOhJe4wXw4aA3IiW1KJhzFcZm jqb7KspXF9QxS9QBFDJSj9XPpf2ZeFtCFxTpwveWA41m3ck+/s46Z8u+GovPKhKmMn72 opf7s2OjLA5+kWRLGV/tywiVIG/+WuwHptJFY2AI6jUr9SEelo82TjyYW3u26noqDYd0 /AZnaT6XFfoK0dDj5SSXTPvChFuzlce6QIYGKTBjTTfKHleKv7VmGAAXsA3VvzpnS7Q7 XAnA==; darn=kvack.org ARC-Authentication-Results: i=1; mx.google.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1770840872; x=1771445672; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=28hr9LjidhOb4+7vDtUZiT7dYr2nuAMqMlceW5mXuOg=; b=BE6CEEcblB5Laiy6YrzjdF2miXoc0puofLt85IVcxPPuP7raR5g151VYcztdQOkT3j 91dYldcdUPPhZ8P3Qf50TrnN5oP3cVmsv7OPwlkWM4x7REz0wKnRNqX6LLFBZaYd6ER5 ZvQDHx+l8ll/Mel62h1l/mOV9F9mq32Nd8//4FprEAHbkxi8gmgRbQ3wmdCeCQQLzJ0l UFJILuWbH/iSWk4LJyFMFW2AEB+Pqsz4mUmrwqn0FMl8hHuCGB2Y2TJWqDXNoVrJ+flX Ha468M0Jr8B4U8D7ewhiMmrcmhZb798wyXHkxRWcOpL8qQiBIPX7mQfP5u+0A+/zVhSx yz6w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770840872; x=1771445672; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=28hr9LjidhOb4+7vDtUZiT7dYr2nuAMqMlceW5mXuOg=; b=wLk0Zar7gjvo1M2nCZvt1fJdKgQNvQPdEMGMeiuhSMLq/DOsHlc0BcYLT3V66BvLwd x5LJpuZqK872Tf0LdF/Ag4hKNRjq+ZpbI3mwtsLsqyoQtSsbbX2b2kjgBoggcuTmzzGt s3pSTeMjteRCCf7XbGYqFGUOXFPKBQJKnINjWm+vV43LFaZqg3glKziyoVZsQwZn7QdQ vVglU+pzbCLZMMAflbfcQ2ykJUz5OARyZrfrBpSpKNe0jEHoFfl9oCm9hLsGTdMBWszR N8y+ooHiWVU5WgISKKvUVVoowwxLjedsvlDZwOwfvlMQLKnsrBjgz+UmPfLpiL0FpOVm 68Nw== X-Forwarded-Encrypted: i=1; AJvYcCWr1bX3n8DeBwtzTUESbLWI50ifyCxqbdkVuuK8gO5bHw7azcwOgpx17hTkUmH8tQ4I8NVS4XXvdQ==@kvack.org X-Gm-Message-State: AOJu0Yxc9mJMOkaHf2vZkGYpksoIzM1RVrPR6eqP1oT5LGB2eiKcktUd YbkvhoHcFm8sKeiiDzLy7dkXHyR1RWE5W3CrO5SW4QLq41efRtOgDnJkD1QjLog4JgliQRgERPS zwsSH0KyOCZG+Gp2w7/PFKWhJNzJDJzE= X-Gm-Gg: AZuq6aJOM2EHbVYnSPFs2cHShDIWe21YZUGmCsqjiP4AtO0BUxiXydCazRYXfqUOl5P 1lW7xeU8H1cs1jJK9aRXtAyRbJvcJjuiUzwCc9ErZpac0MspwdgpXB8kLgEg7XZoyg4Q3cMrS8A g++eKepacKqojpU4YzdpceX8JaJf92xUJoW2zGgldFcz0XzeL1339NFFE6t1QFQpRd+6JihTcS5 qsq8gTYs8B1riZhiC0881IUBA8gSfivIIVujtjdjTLHLcx3aFqS2psGMpaE07WdeUi5SuSUi/+7 Js4D39M2p4wIhkLNQOIFBR5CUMb8ZLfGauAM+t9Iyg== X-Received: by 2002:a17:907:a08a:b0:b8e:64e:1ed with SMTP id a640c23a62f3a-b8f8f72d91emr17643566b.50.1770840871149; Wed, 11 Feb 2026 12:14:31 -0800 (PST) MIME-Version: 1.0 References: <20260211103141.3215197-1-rppt@kernel.org> <20260211103141.3215197-4-rppt@kernel.org> In-Reply-To: <20260211103141.3215197-4-rppt@kernel.org> From: Magnus Lindholm Date: Wed, 11 Feb 2026 21:14:19 +0100 X-Gm-Features: AZwV_QgdPAvH3hw0825YIt93LQPupYFvh_AV-2zMkwGhubC87cSa2iVxpdoZwag Message-ID: Subject: Re: [PATCH v3 3/4] arch, mm: consolidate empty_zero_page To: Mike Rapoport Cc: Andrew Morton , Andreas Larsson , Borislav Petkov , Brian Cain , Catalin Marinas , "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 , 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 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Queue-Id: 3891F1C0007 X-Rspamd-Server: rspam07 X-Stat-Signature: 36sqburzgaxztf9s6uhghck39y7tfrsx X-HE-Tag: 1770840872-324308 X-HE-Meta: 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 4ZeWHtz6 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 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 Wed, Feb 11, 2026 at 11:32=E2=80=AFAM Mike Rapoport wr= ote: > > From: "Mike Rapoport (Microsoft)" > > Reduce 22 declarations of empty_zero_page to 3 and 23 declarations of > ZERO_PAGE() to 4. > > Every architecture defines empty_zero_page that way or another, but for t= he > most of them it is always a page aligned page in BSS and most definitions > of ZERO_PAGE do virt_to_page(empty_zero_page). > > Move Linus vetted x86 definition of empty_zero_page and ZERO_PAGE() to th= e > core MM and drop these definitions in architectures that do not implement > colored zero page (MIPS and s390). > > ZERO_PAGE() remains a macro because turning it to a wrapper for a static > inline causes severe pain in header dependencies. > > For the most part the change is mechanical, with these being noteworthy: > > * alpha: aliased empty_zero_page with ZERO_PGE that was also used for boo= t > parameters. Switching to a generic empty_zero_page removes the aliasing > and keeps ZERO_PGE for boot parameters only > * arm64: uses __pa_symbol() in ZERO_PAGE() so that definition of > ZERO_PAGE() is kept intact. > * m68k/parisc/um: allocated empty_zero_page from memblock, > although they do not support zero page coloring and having it in BSS > will work fine. > * sparc64 can have empty_zero_page in BSS rather allocate it, but it > can't use virt_to_page() for BSS. Keep it's definition of ZERO_PAGE() > but instead of allocating it, make mem_map_zero point to > empty_zero_page. > * sh: used empty_zero_page for boot parameters at the very early boot. > Rename the parameters page to boot_params_page and let sh use the gener= ic > empty_zero_page. > * hexagon: had an amusing comment about empty_zero_page > > /* A handy thing to have if one has the RAM. Declared in head.S *= / > > that unfortunately had to go :) > > Acked-by: Helge Deller # parisc > Tested-by: Helge Deller # parisc > Reviewed-by: Christophe Leroy (CS GROUP) > Acked-by: Dave Hansen > Acked-by: Catalin Marinas > Signed-off-by: Mike Rapoport (Microsoft) > --- > arch/alpha/include/asm/pgtable.h | 6 ------ > diff --git a/arch/alpha/include/asm/pgtable.h b/arch/alpha/include/asm/pg= table.h > index 90e7a9539102..12a3c5f8ece8 100644 > --- a/arch/alpha/include/asm/pgtable.h > +++ b/arch/alpha/include/asm/pgtable.h > @@ -125,12 +125,6 @@ struct vm_area_struct; > */ > #define pgprot_noncached(prot) (prot) > > -/* > - * ZERO_PAGE is a global shared page that is always zero: used > - * for zero-mapped memory areas etc.. > - */ > -#define ZERO_PAGE(vaddr) (virt_to_page(ZERO_PGE)) > - > /* > * On certain platforms whose physical address space can overlap KSEG, > * namely EV6 and above, we must re-twiddle the physaddr to restore the This looks good from an Alpha perspective Acked-by: Magnus Lindholm