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 1DCA7CD98D2 for ; Thu, 11 Jun 2026 12:22:07 +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=uG/oiGe08GlbvOXLBMnHpg/vQFnYJfTe59/7gdd1dCo=; b=2ajygCE9P1iIZq2vTQzO8jkjEc rxqs31fqffYTLwJ5s91pyEVKKXWqMnnvOaTdY8FkqrPIxIAhGfo2GK4M5zfu7paHQ8vFuUDbsRFy0 E432ChuBAeKElBucBWjJT2wpJKhfk0SnskIPy0taWlw6Giw/sh9UqmLh5QOAN8AKiZauXlLJurqP7 nIzL1AS1QdKxbWoIoexbmnoMDjCdAW/nzyziAqpbYmk9SJ1fvk9I5hsitlq4Uq8hSAQCx2SlC0m8X q4hDuCCXm3AcXtNgVb5MI+3y09tnoDS3r3CaTgkJZ8go6uKrN1G77Sr6ueU8uiTTCkEoWsLbZyr9g AiQ/O+sQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wXeQ3-00000009NiF-0MXL; Thu, 11 Jun 2026 12:21:59 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wXeQ1-00000009Ni7-2aRA for linux-arm-kernel@lists.infradead.org; Thu, 11 Jun 2026 12:21:57 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 9DEF26001A; Thu, 11 Jun 2026 12:21:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4AD611F00893; Thu, 11 Jun 2026 12:21:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781180516; bh=uG/oiGe08GlbvOXLBMnHpg/vQFnYJfTe59/7gdd1dCo=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=fbpkLaAUNB5lDGQL5XNJOaEhHZC8SrUA6FP+YYfXO1mF0LhjRwfV80QyGDS7dypXs VTvtMO9Pxww8G7urP/7Bxty6xRBLgkmY6Pg6LBD6ZFblw3+O62YaQdLK4Dm+j+sEmY NriZAlA0t3jmY17Y6yFOS94bJAn5yM+1tKyUdKIEyqQxtiay4BkYuq+C43jkohmB1L adSMXsevafXL+VS8tfCPDR/n8pxUMRCQgnX9JCqGlo/IJhI4S4SJ+jk2UztjSM9M7C DNAOQ9wuzIZXfsmi5GBGAdtOWxZNmY0Wn6UdyYS3KUtOXbBfDT1vIjtnrpTul2NqPy iE3LRC6MNYDKw== Message-ID: Date: Thu, 11 Jun 2026 14:21:45 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v2 1/3] mm/huge_memory: make persistent huge zero folio read-only To: Lance Yang Cc: akpm@linux-foundation.org, xueyuan.chen21@gmail.com, linux-mm@kvack.org, 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, luto@kernel.org, peterz@infradead.org, hpa@zytor.com, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, yang@os.amperecomputing.com, jannh@google.com, dave.hansen@intel.com References: <8c36a91d-288f-4ffb-b2ec-41e3ef789d72@kernel.org> <20260611115817.59353-1-lance.yang@linux.dev> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit 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 6/11/26 13:58, Lance Yang wrote: > > On Thu, Jun 11, 2026 at 01:28:58PM +0200, David Hildenbrand (Arm) wrote: >> On 6/10/26 04:15, Lance Yang wrote: >>> >>> >>> Right, this came from the RFC v1 discussion[1]. David preferred a page- >>> range helper for possible future non-folio callers, not something folio- >>> only. >>> >>> Of course, we could also add a folio wrapper on top of that if needed :) >> >> Best to document that as part of the patch description: we don't really expect >> to have a lot of read-only folios in the near future (zero page is rather >> special; maybe it won't even be a folio in the future). > > Ah, good to know, thanks. Will spell that out in RFC v3. > > Maybe something like this? > > The huge zero page is pretty special case, and maybe it won't even be a > folio in the future. Since read-only folios are unlikely to become a > common thing, a page-range helper is the cleaner fit. Right. And if read-only folios in FSes become a real thing, we can always add infrastructure for that. -- Cheers, David