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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1C8E5C48297 for ; Mon, 12 Feb 2024 14:11:06 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6C2D56B0071; Mon, 12 Feb 2024 09:11:06 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 672A06B0072; Mon, 12 Feb 2024 09:11:06 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5615B6B0074; Mon, 12 Feb 2024 09:11:06 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 442426B0071 for ; Mon, 12 Feb 2024 09:11:06 -0500 (EST) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id D19F11209BC for ; Mon, 12 Feb 2024 14:11:05 +0000 (UTC) X-FDA: 81783338490.26.77E6755 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf17.hostedemail.com (Postfix) with ESMTP id 04A1A40020 for ; Mon, 12 Feb 2024 14:11:02 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf17.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1707747063; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=cAm0Wx43i+n9zjJ1srkhHu0aM7vsVjg3ETgreH4eCMU=; b=3B1aJNs5/7UVKChBvmY0NXwZMWkX755dcxcFhhy4wnMWAe6arppg12NxgF8LHF2umhGm/R xMcD0I5bOmSnseI5FBdkOcLV04quwplAlPvkdaiU05H+tDFarlwI9EGnaGqv+GA/fZ6kRr y0Ua2/HsiUs5ZHVQRnC435ocTzYzLG0= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf17.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1707747063; a=rsa-sha256; cv=none; b=SP0AVFbV+HNwT5UwSpXlCMQZsNS8skhBQs8bYrqfKmbt7w2iTl//TY8WGxL1oZPFzE0E5O lJj/Zu49DCEWB+kZRu+GezGti3dZwOTIPKjOBsh95kJgJr95PkXb/lMuB9ytpnGv+JdCHh 7OBDPDXYxM+d3+EVzcS3AGnrWJMV6yo= 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 16DF8DA7; Mon, 12 Feb 2024 06:11:43 -0800 (PST) Received: from [10.57.78.115] (unknown [10.57.78.115]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8A1673F7BD; Mon, 12 Feb 2024 06:10:57 -0800 (PST) Message-ID: Date: Mon, 12 Feb 2024 14:10:55 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 03/25] mm: Make pte_next_pfn() a wrapper around pte_advance_pfn() Content-Language: en-GB To: David Hildenbrand , Catalin Marinas , Will Deacon , Ard Biesheuvel , Marc Zyngier , James Morse , Andrey Ryabinin , Andrew Morton , Matthew Wilcox , Mark Rutland , Kefeng Wang , John Hubbard , Zi Yan , Barry Song <21cnbao@gmail.com>, Alistair Popple , Yang Shi , Nicholas Piggin , Christophe Leroy , "Aneesh Kumar K.V" , "Naveen N. Rao" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" Cc: linux-arm-kernel@lists.infradead.org, x86@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20240202080756.1453939-1-ryan.roberts@arm.com> <20240202080756.1453939-4-ryan.roberts@arm.com> From: Ryan Roberts In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 04A1A40020 X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: rojhk3cucw3exnwiz4pieokoxwsgrub3 X-HE-Tag: 1707747062-506329 X-HE-Meta: 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 5yDqYQCg zwWZ7augK6NdYXM3TbS8+PgT1uD4jpUyyOMJcMR+CGqiXLAFlBz5tXpdK14uJolE2xa4Mv2W8LWDBgHH9s5BVkXKp3HHj/oNhuwvFVAcpw2sJ/j1gP6iwhsEqHdOqbCK3c2pN5UKljuk8Tco1neuAlFhy6FYGKgQpqgfXReHM6VIHoP9KriNzPBk6GpQgOlABaZqaQxyyHlwdB/0XO4WHhhgvJhod6PH08gJIbQTLQhraDB4E5EMYgJQLUGG+8boQR+FXrvwZ8WVOUoMbNYjY9+yFOWeaIMQrmFqnMSjrQ8xa6lifY/gV84Swut2GN1WaBtFB6U1tfwuFv03PLtEXKHiGARHrS09klgCZ X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 12/02/2024 12:14, David Hildenbrand wrote: > On 02.02.24 09:07, Ryan Roberts wrote: >> The goal is to be able to advance a PTE by an arbitrary number of PFNs. >> So introduce a new API that takes a nr param. >> >> We are going to remove pte_next_pfn() and replace it with >> pte_advance_pfn(). As a first step, implement pte_next_pfn() as a >> wrapper around pte_advance_pfn() so that we can incrementally switch the >> architectures over. Once all arches are moved over, we will change all >> the core-mm callers to call pte_advance_pfn() directly and remove the >> wrapper. >> >> Signed-off-by: Ryan Roberts >> --- >>   include/linux/pgtable.h | 8 +++++++- >>   1 file changed, 7 insertions(+), 1 deletion(-) >> >> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h >> index 5e7eaf8f2b97..815d92dcb96b 100644 >> --- a/include/linux/pgtable.h >> +++ b/include/linux/pgtable.h >> @@ -214,9 +214,15 @@ static inline int pmd_dirty(pmd_t pmd) >>       #ifndef pte_next_pfn >> +#ifndef pte_advance_pfn >> +static inline pte_t pte_advance_pfn(pte_t pte, unsigned long nr) >> +{ >> +    return __pte(pte_val(pte) + (nr << PFN_PTE_SHIFT)); >> +} >> +#endif >>   static inline pte_t pte_next_pfn(pte_t pte) >>   { >> -    return __pte(pte_val(pte) + (1UL << PFN_PTE_SHIFT)); >> +    return pte_advance_pfn(pte, 1); >>   } >>   #endif >>   > > I do wonder if we simply want to leave pte_next_pfn() around? Especially patch > #4, #6 don't really benefit from the change? So are the other set_ptes() > implementations. > > That is, only convert all pte_next_pfn()->pte_advance_pfn(), and leave a > pte_next_pfn() macro in place. > > Any downsides to that? The downside is just having multiple functions that effectively do the same thing. Personally I think its cleaner and easier to understand the code with just one generic function which we pass 1 to it where we only want to advance by 1. In the end, there are only a couple of places where pte_advance_pfn(1) is used, so doesn't really seem valuable to me to maintain a specialization. Unless you feel strongly that we need to keep pte_next_pfn() then I'd prefer to leave it as I've done in this series. > This patch here would become: > > #ifndef pte_advance_pfn > static inline pte_t pte_advance_pfn(pte_t pte, unsigned long nr) > { >     return __pte(pte_val(pte) + (nr << PFN_PTE_SHIFT)); > } > #endif > > #ifndef pte_next_pfn > #define pte_next_pfn(pte) pte_advance_pfn(pte, 1) > #endif > > As you convert the three arches, make them define pte_advance_pfn and udnefine > pte_next_pfn. in the end, you can drop the #ifdef around pte_next_pfn here. >