From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A522C338900; Wed, 4 Feb 2026 16:56:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770224214; cv=none; b=rS51BR2e0G6smAxFTK4/ONsJzuwrLMFyBeFlZJyV/SM7QevjB1MWYur4JrYtJDuP0uPJfozpofsLYbP4QLOsmihO1iCkQxLwLYfmvhW5HBomEo2iqkeHx0ZWD1d5hhfxQ2nNiLn9rtvJ5+Bhz3ItxY8nvF5Eu6Qn+60QTXGs7h4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770224214; c=relaxed/simple; bh=PdJwL2FfZcrZlGmwfIl75VdtZDNdmDKvW0Pqu/rV0mU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=GcDlWjbHr5lwgFCRPkcAECfJpvXSHgxfqcKAbuDR9D+SiISGt0PnF7qwasYK0aaTui7b/oOiSjLas18MUfa4ye5lMvtdTAMkzt9nvK81sb6bRuAy41jYpwnsIVRgkzVPBMX2gNtYKz9yJTQT83fuOU6xT3NpdngnGVaeqrlmaSc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=n3b6fFMj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="n3b6fFMj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9369AC4CEF7; Wed, 4 Feb 2026 16:56:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770224214; bh=PdJwL2FfZcrZlGmwfIl75VdtZDNdmDKvW0Pqu/rV0mU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=n3b6fFMj5xAka9Jh+F8qYvBKS4/lBho0sJ4vU7OzTxn6zTyTDuW4AH581/BU6NVbt POaPOLGC6z4LIY/GqI0emhIU2Icmf84HWLDkd8F9dX92Y4I5K1oi0iHTDmffqqNjvx PHy01L791lxZTaXw7Y5VnhB4pofkh6rxofpjA63xJwQEkD9lDd7625LUoA84ZfDUko TxXtZHx6ugQRzJGIQIRZ0RzEsTh0/kWjXByqXVBZ1/3HSpGyP91d9H4BGzE+R58At1 x3obFM3m0s8LCh4QU7gv0ANGJnJibag29UlUvdQXsu8OUQSqiELG/wU+4zMbhYP01B vLdAeSVEdOHwQ== Message-ID: <2ce0e684-de54-43ec-be7d-c58bbffb3f4e@kernel.org> Date: Wed, 4 Feb 2026 17:56:45 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCHv6 06/17] LoongArch/mm: Align vmemmap to maximal folio size 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> <20260202155634.650837-7-kas@kernel.org> From: "David Hildenbrand (arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2/2/26 16:56, Kiryl Shutsemau wrote: > The upcoming change to the HugeTLB vmemmap optimization (HVO) requires > struct pages of the head page to be naturally aligned with regard to the > folio size. > > Align vmemmap to MAX_FOLIO_NR_PAGES. > > Signed-off-by: Kiryl Shutsemau > --- > arch/loongarch/include/asm/pgtable.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h > index c33b3bcb733e..f9416acb9156 100644 > --- a/arch/loongarch/include/asm/pgtable.h > +++ b/arch/loongarch/include/asm/pgtable.h > @@ -113,7 +113,8 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]; > min(PTRS_PER_PGD * PTRS_PER_PUD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE, (1UL << cpu_vabits) / 2) - PMD_SIZE - VMEMMAP_SIZE - KFENCE_AREA_SIZE) > #endif > > -#define vmemmap ((struct page *)((VMALLOC_END + PMD_SIZE) & PMD_MASK)) > +#define VMEMMAP_ALIGN max(PMD_SIZE, MAX_FOLIO_NR_PAGES * sizeof(struct page)) > +#define vmemmap ((struct page *)(ALIGN(VMALLOC_END, VMEMMAP_ALIGN))) Same comment, the "MAX_FOLIO_NR_PAGES * sizeof(struct page)" is just black magic here and the description of the situation is wrong. Maybe you want to pull the magic "MAX_FOLIO_NR_PAGES * sizeof(struct page)" into the core and call it #define MAX_FOLIO_VMEMMAP_ALIGN (MAX_FOLIO_NR_PAGES * sizeof(struct page)) But then special case it base on (a) HVO being configured in an (b) HVO being possible #ifdef HUGETLB_PAGE_OPTIMIZE_VMEMMAP && is_power_of_2(sizeof(struct page) /* A very helpful comment explaining the situation. */ #define MAX_FOLIO_VMEMMAP_ALIGN (MAX_FOLIO_NR_PAGES * sizeof(struct page)) #else #define MAX_FOLIO_VMEMMAP_ALIGN 0 #endif Something like that. -- Cheers, David