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 72D0DC021A0 for ; Mon, 17 Feb 2025 04:36:05 +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=+tOQ187njbe5z4RyF0k4IJnhNqgW/KM/sOwzxrx3J+s=; b=GEUHfpq0iivbx22cSNJWqb93Ui npc5uQ+ZU1rJ2F/dAEyahICpLP8gIKg35+hQbGV/QRtsdrb/LudbkvCqVYnhdS4MDCpfVJ/hkM7uy OgQmXmd+hni2PrMOVE4Onco3FXJRloB8bsIdKhVAlxaRSO+KgXT6THnJ0zD5gaZDW4QT4qlCLEilu qkGTp1857fshH8VHAOhjHYyzAPQnR6SEXqw6JHkT+ucVjry8wMU1c+kEPcf/lukslS2aIMpDMgNvT f2QwEQQaUuZYmOs6Te9aJs6RirAi2LkTVwHZDAHAkdhcnAObgg+pn8bhCz5shCmSPt/wpuASY90wW BartPxfw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tjsrM-00000003Fk5-0It1; Mon, 17 Feb 2025 04:35:56 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tjsp9-00000003FTd-2NWf for linux-arm-kernel@lists.infradead.org; Mon, 17 Feb 2025 04:33:40 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3077E1063; Sun, 16 Feb 2025 20:33:58 -0800 (PST) Received: from [10.162.16.135] (unknown [10.162.16.135]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4C2B43F59E; Sun, 16 Feb 2025 20:33:34 -0800 (PST) Message-ID: <72f188c5-c078-4ff5-81a6-3a0c8b2edaea@arm.com> Date: Mon, 17 Feb 2025 10:03:31 +0530 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 12/16] arm64/mm: Support huge pte-mapped pages in vmap To: Ryan Roberts , Catalin Marinas , Will Deacon , Muchun Song , Pasha Tatashin , Andrew Morton , Uladzislau Rezki , Christoph Hellwig , Mark Rutland , Ard Biesheuvel , Dev Jain , Alexandre Ghiti , Steve Capper , Kevin Brodsky Cc: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20250205151003.88959-1-ryan.roberts@arm.com> <20250205151003.88959-13-ryan.roberts@arm.com> <9a0d3009-18fc-4b53-941a-b6d830fce36a@arm.com> <21da59a8-165d-4423-a00d-d5859f42ec11@arm.com> <0dd74f57-902a-4a6d-9f77-31963b5953d1@arm.com> Content-Language: en-US From: Anshuman Khandual In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250216_203339_643287_E69F89F1 X-CRM114-Status: GOOD ( 13.53 ) 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 2/13/25 14:39, Ryan Roberts wrote: > >>>>> +#define arch_vmap_pte_range_map_size arch_vmap_pte_range_map_size >>>>> +static inline unsigned long arch_vmap_pte_range_map_size(unsigned long addr, >>>>> + unsigned long end, u64 pfn, >>>>> + unsigned int max_page_shift) >>>>> +{ >>>>> + if (max_page_shift < CONT_PTE_SHIFT) >>>>> + return PAGE_SIZE; >>>>> + >>>>> + if (end - addr < CONT_PTE_SIZE) >>>>> + return PAGE_SIZE; >>>>> + >>>>> + if (!IS_ALIGNED(addr, CONT_PTE_SIZE)) >>>>> + return PAGE_SIZE; >>>>> + >>>>> + if (!IS_ALIGNED(PFN_PHYS(pfn), CONT_PTE_SIZE)) >>>>> + return PAGE_SIZE; >>>>> + >>>>> + return CONT_PTE_SIZE; >>>> >>>> A small nit: >>>> >>>> Should the rationale behind picking CONT_PTE_SIZE be added here as an in code >>>> comment or something in the function - just to make things bit clear. >>> >>> I'm not sure what other size we would pick? >> >> The suggestion was to add a small comment in the above helper function explaining >> the rationale for various conditions in there while returning either PAGE_SIZE or >> CONT_PTE_SIZE to improve readability etc. > > OK I've added the following: > > /* > * If the block is at least CONT_PTE_SIZE in size, and is naturally > * aligned in both virtual and physical space, then we can pte-map the > * block using the PTE_CONT bit for more efficient use of the TLB. > */ Sounds good, thanks !