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 94F3FCD6E55 for ; Mon, 1 Jun 2026 15:46:45 +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:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=+PZyLMmZBGq0lNbALF3xmrMJy0VM7McUCcXTF9FzQnQ=; b=1ZhlRFHMSXmTnGaNbELDied9YU WZkgDC9D1CVvf5oAKqS5vDLwVoy2PdLRliYSFB9Vlr9tlEn+7IlBb7JBB/YBx2oIoSOqIEyXHSCBo qJ9grB8mZIvQJOIHBHsebcTOoQXat9HEXQMB/KKYJOuvIcZy+AsB8FlQOMQy9bJXgo9yJgbyK3nP9 jpLT5NnZR/642kd1vIZ9Ui1Zv66aJck3de+cU87Qd+ziMb9JoHx5WMmmZw4XyPEXpmEYZ8Mt/9+Tx LyfR6Dd5IUyhi9W8+Bt9BRlSrICDwLgUIn0OXG1jlBuJRpMd59dJadAusDbW0yipCVkzt1DB3GZh5 TtiGvGxA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wU4qc-0000000BPBN-1D52; Mon, 01 Jun 2026 15:46:38 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wU4qZ-0000000BPAY-3EQB for linux-arm-kernel@lists.infradead.org; Mon, 01 Jun 2026 15:46:36 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 0C93844342; Mon, 1 Jun 2026 15:46:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6E3411F00893; Mon, 1 Jun 2026 15:46:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780328794; bh=+PZyLMmZBGq0lNbALF3xmrMJy0VM7McUCcXTF9FzQnQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=DmC1Ux43Yo2uzBrTN9Nkt/+7feAF97Tn2ZFy51PUjV7C5QpLrET/wsB+hl78Eoefb IvjDgSgBnUlVETwpkXRB/KsnLRXs1r4SwwZonL2+uI/XwaB5IPkZDlVZrlbGY/PsrJ krH16VbOz0ySObXNbBZiUDwgkq1kPBhZOdXCraY53mjhhiu07oWyf6vmf3IL+Kmu1v noBVrDAJZuyH8oBskjsEJ+CVSTs4a25x0Ny5lo9htJezMeezdmZ+5D94aXDrtwaXEV ZcD31tEC3pzGK+rcg6WeXsa6YZp1OJiXiCtFgvs604GFcj+FZV8Roiw8Kmy3P+HkhO qiEmRgqGLgx+g== Message-ID: <9979fa87-88ef-4baf-8592-502ff4888085@kernel.org> Date: Mon, 1 Jun 2026 17:46:27 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 1/3] mm: make persistent huge zero folio read-only To: Lance Yang , Dave Hansen , Xueyuan chen Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, x86@kernel.org, catalin.marinas@arm.com, will@kernel.org, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, ljs@kernel.org, ziy@nvidia.com, baolin.wang@linux.alibaba.com, akpm@linux-foundation.org, ryan.roberts@arm.com, dev.jain@arm.com, yang@os.amperecomputing.com, jannh@google.com, linux-mm@kvack.org References: <20260527035607.14919-1-xueyuan.chen21@gmail.com> <20260527035607.14919-2-xueyuan.chen21@gmail.com> <4e0696ee-895c-486d-aacc-71146f0e9047@intel.com> <929875a2-9e94-4dbc-9c98-b342ccc3f4e2@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260601_084635_870461_4B766378 X-CRM114-Status: GOOD ( 12.00 ) X-BeenThere: linux-arm-kernel@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-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 6/1/26 17:43, Lance Yang wrote: > > > On 2026/6/1 21:49, David Hildenbrand (Arm) wrote: >> On 5/27/26 17:55, Dave Hansen wrote: >>> CONFIG_READONLY_HUGE_ZERO_FOLIO >>> >>> All of the #ifdeffery needs to die, IMNHO. >>> >>> This function is also a bad idea. There is nothing "huge zero" specific >>> about it. It takes any old folio and tries to make it read only. >>> >>> Just make it: >>> >>>     bool __init arch_make_folio_readonly(struct folio *folio) >>> >> >> I'm not sure whether we want a folio-based interface, though. >> >> This will likely be the only folio (that will actually have a "struct folio" in >> the future) compound page we'll ever mark read-only ... whereby I'd guess we'd >> want other non-folio pages to be read-only in the future (encryption keys etc, >> maybe?). >> >> So I'd instead use a page-range based interface or sth like that. > > Just to check, did you mean something like: > > bool arch_make_pages_readonly(struct page *page, int nr_pages); > > ? > > So it can work on pages as well, not only folios :) Yes, that would have been my first idea if we want to easily allow other reuse in the future. Of course, we could add a folio wrapper that will likely mostly be used by a single user ... :) -- Cheers, David