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 X-Spam-Level: X-Spam-Status: No, score=-10.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DE273C433E0 for ; Thu, 11 Mar 2021 07:53:57 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 430D561574 for ; Thu, 11 Mar 2021 07:53:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 430D561574 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:Cc:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Jh45bhPgcsryKRlSkOAZSw8fFBI92unxII08zDD2ZD0=; b=LJKz2sxbLe/bbWSa58qs3x3TB 7vrx0xO6yxphjTs4Q2KYiD0H10SZTShMEhUSG0+G2kxwMsdUMDju/7nHM6z74pEWluVCQm6KWDWI1 fbwjTKpnaYcQ2CUwhasV/zBohipSaY2EYEE3ekNFZAGV78iJXEEWcfb3hl6TcupR5ArlmHn2FFqcE pN1kZqMU99J7yHPC7IlQV7EIWAtik7xHDCrGI2hYRyaDWRh7Y//oqUqWuz8EZKRkU7GCiaS4h5l2c 10CpYABnb8qC/xS+GylifBgQt95rmzQ9UJnrbTBDjvt1IJH9k33cLFJ2cSuYF13Cdp1Hj7DihIYJ3 yAfn8SV0Q==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lKG7R-008dRH-6M; Thu, 11 Mar 2021 07:52:29 +0000 Received: from foss.arm.com ([217.140.110.172]) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lKG7N-008dQZ-3x for linux-arm-kernel@lists.infradead.org; Thu, 11 Mar 2021 07:52:26 +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 9C9801FB; Wed, 10 Mar 2021 23:52:19 -0800 (PST) Received: from [10.163.66.3] (unknown [10.163.66.3]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D9E2B3F70D; Wed, 10 Mar 2021 23:52:16 -0800 (PST) Subject: Re: [RFC] mm: Enable generic pfn_valid() to handle early sections with memmap holes To: Mike Rapoport Cc: linux-mm@kvack.org, Russell King , Catalin Marinas , Will Deacon , Andrew Morton , David Hildenbrand , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <1615174073-10520-1-git-send-email-anshuman.khandual@arm.com> From: Anshuman Khandual Message-ID: <003d8a4b-9687-3e9a-c27b-908db280b44c@arm.com> Date: Thu, 11 Mar 2021 13:22:53 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210311_075225_349653_636227EF X-CRM114-Status: GOOD ( 21.29 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 3/8/21 2:25 PM, Mike Rapoport wrote: > Hi Anshuman, > > On Mon, Mar 08, 2021 at 08:57:53AM +0530, Anshuman Khandual wrote: >> Platforms like arm and arm64 have redefined pfn_valid() because their early >> memory sections might have contained memmap holes caused by memblock areas >> tagged with MEMBLOCK_NOMAP, which should be skipped while validating a pfn >> for struct page backing. This scenario could be captured with a new option >> CONFIG_HAVE_EARLY_SECTION_MEMMAP_HOLES and then generic pfn_valid() can be >> improved to accommodate such platforms. This reduces overall code footprint >> and also improves maintainability. > > I wonder whether arm64 would still need to free parts of its memmap after free_unused_memmap() is applicable when CONFIG_SPARSEMEM_VMEMMAP is not enabled. I am not sure whether there still might be some platforms or boards which would benefit from this. Hence lets just keep this unchanged for now. > the section size was reduced. Maybe the pain of arm64::pfn_valid() is not > worth the memory savings anymore? arm64 pfn_valid() special case was primarily because of MEMBLOCK_NOMAP tagged memory areas, which are reserved by the firmware. > >> Commit 4f5b0c178996 ("arm, arm64: move free_unused_memmap() to generic mm") >> had used CONFIG_HAVE_ARCH_PFN_VALID to gate free_unused_memmap(), which in >> turn had expanded its scope to new platforms like arc and m68k. Rather lets >> restrict back the scope for free_unused_memmap() to arm and arm64 platforms >> using this new config option i.e CONFIG_HAVE_EARLY_SECTION_MEMMAP. > > The whole point of 4f5b0c178996 was to let arc and m68k to free unused > memory map with FLATMEM so they won't need DISCONTIGMEM or SPARSEMEM. So > whatever implementation there will be for arm/arm64, please keep arc and > m68k functionally intact. Okay. Will protect free_unused_memmap() on HAVE_EARLY_SECTION_MEMMAP_HOLES config as well. diff --git a/mm/memblock.c b/mm/memblock.c index d9fa2e62ab7a..11b624e94127 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -1927,8 +1927,11 @@ static void __init free_unused_memmap(void) unsigned long start, end, prev_end = 0; int i; - if (!IS_ENABLED(CONFIG_HAVE_EARLY_SECTION_MEMMAP_HOLES) || - IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP)) + if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP)) + return; + + if (!IS_ENABLED(CONFIG_HAVE_EARLY_SECTION_MEMMAP_HOLES) && + !IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID)) return; _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel