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 128D0EE2086 for ; Fri, 6 Feb 2026 10:42:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id: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=DeiQ0A30/w4WwBZS8W4VAgthMJxJex9DIqx7POzLwto=; b=IJFlRGOM9dOifT 7lGit5RAlH4FzhfbBZyn+lVD6wRTwCzW9xobFprOF5HrU2Z6ZSrP3VL0e+IBB89muYu5O4Hvk9c/q ziIqUW/PYkcrMluHmthyTTaLc0IBk2uWZfoOk1OUBZt0JOxjuhb64NRHyw7M8pQnvepS2lkFkHmud VkdPb6D8exw+faKWmJNFXQ07Ny8gWS5zxMHcamn0DidOO2xtyDsHF/6GBAhqHctF5GJTbnru3moCx 99az+Pxnm6n/rY7X7Z2sKybOTj6r17ZzDryknZcDmp4RnD61E+llUv5KXoHn4nUI9je7gSM9sNOev tetyd0q4rfrGoXH24C+w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1voJI5-0000000BBjA-2yPh; Fri, 06 Feb 2026 10:42:21 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1voJI3-0000000BBj3-1E6j for linux-riscv@lists.infradead.org; Fri, 06 Feb 2026 10:42:20 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 3316360051; Fri, 6 Feb 2026 10:42:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CAA05C116C6; Fri, 6 Feb 2026 10:42:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770374537; bh=X4ulH2AmDkCSg3stSWU0qmNiUtFh+CTtBIZg9eTnXM0=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=VTysHtsFbDZOc9nla0Q2lgBis/brgO6Tu+kf3ZjW0lCZpL1uJplM9eZTkXQhCcum2 UIQVwE1+A3z9/osnfEUHa5wrcr52RX4ivjXktLIzY5oVFuwODBON2ufk5tTgU6mn+R kRQjtEeQq2irifXeO/1G3CFjPn3stmMk/VvAx3qvWB8gbBiWAQl6yd0+kYztL1a+QJ eagSYMaSu7JIt54TiZMwJU+j3SfNPW7mc3mRGstPV06L/k2NOUTqClojWUxdl8PEiw /vumUJqdqpNOYsec/0f6JZTDY41m2mszc4Rs+BB36RPHPk/B4ZAjutUf6q1FNZNSrq eP+Xw8P8QMVAg== Message-ID: <0ecdd75e-ccd8-4217-a409-51da756ff1fe@kernel.org> Date: Fri, 6 Feb 2026 11:42:10 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCHv6 17/17] mm/slab: Use compound_head() in page_slab() To: Kiryl Shutsemau , Andrew Morton , Muchun Song , Matthew Wilcox , Usama Arif , Frank van der Linden Cc: Oscar Salvador , Mike Rapoport , Vlastimil Babka , Lorenzo Stoakes , Zi Yan , Baoquan He , Michal Hocko , Johannes Weiner , Jonathan Corbet , Huacai Chen , WANG Xuerui , Palmer Dabbelt , Paul Walmsley , Albert Ou , Alexandre Ghiti , kernel-team@meta.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org References: <20260202155634.650837-1-kas@kernel.org> <20260202155634.650837-18-kas@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset="us-ascii"; Format="flowed" Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On 2/2/26 16:56, Kiryl Shutsemau wrote: > page_slab() contained an open-coded implementation of compound_head(). > > Replace the duplicated code with a direct call to compound_head(). > > Signed-off-by: Kiryl Shutsemau > > --- > > I am not sure if this open-coded version is intentional and required for > memdesc transition. Drop the patch if it is. commit 2bcd3800f2da1be13b972858f63c66d035b1ec6d Author: Matthew Wilcox (Oracle) Date: Thu Nov 13 00:09:15 2025 +0000 slab: Reimplement page_slab() In order to separate slabs from folios, we need to convert from any page in a slab to the slab directly without going through a page to folio conversion first. Up to this point, page_slab() has followed the example of other memdesc converters (page_folio(), page_ptdesc() etc) and just cast the pointer to the requested type, regardless of whether the pointer is actually a pointer to the correct type or not. That changes with this commit; we check that the page actually belongs to a slab and return NULL if it does not. Other memdesc converters will adopt this convention in future. I think using compound_head() is fine. For memdescs the function has to be changed to lookup the memdesc either way, and not go through the head page. Acked-by: David Hildenbrand (Arm) -- Cheers, David _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv