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=-15.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, 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 72C40C433ED for ; Thu, 22 Apr 2021 09:05:54 +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 9445E613B0 for ; Thu, 22 Apr 2021 09:05:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9445E613B0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.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-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:Subject: From:References:Cc:To:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=qbmdWTJo5E3e4hD9BK+hQxuPtOIE9e1l7qGPbi8EfYo=; b=Skn/ZW1jc4otBG91gZCGwBSlw Tj/uE/WVJwtJL/8lQ2kA3/GqFdZy1as7XHY+jH4zsj+MIAly2puT8hKKMZmNCWe0JvjwUiovY6jLj la1IHcqfAL6y3x50OGXUfZRPrQWkTINYhYsKnzul5hciMNESPqzbRwtVAnIcBn+j/gBY2bjVWOml/ opC7cFU5vPMNYCBD8+H7L7tFcerhTrOKCqZQ38q1TmrHgvmvzZSLlRfEgMixNSjDZTkrb8ZLMw0hA O1silIfXYhHYUE2dIc2G0TkI4yMk8bn/Omfi5ApRiTLYTp1KII8pGKYRmsqax3tugvYoMzRo3Vay/ dGuNaajJw==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lZVFk-00GKpJ-5C; Thu, 22 Apr 2021 09:04:04 +0000 Received: from bombadil.infradead.org ([2607:7c80:54:e::133]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lZVFf-00GKoq-Oq for linux-arm-kernel@desiato.infradead.org; Thu, 22 Apr 2021 09:03:59 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:Subject:From:References :Cc:To:Sender:Reply-To:Content-ID:Content-Description; bh=tBPIqE9re75l34eoDms0OtxOrGa4ChUZqthAcy2zOrM=; b=sUdZFbDfJSiT2tak17NR972yNS 3xlYJK9JDEgFL67mZ5Y+bK3AfLeEE8JcLrAkQyNy9RTCQJ+0A1MHb7KX7O7BAO5O3Tki+0xWMtSrz 3HwALUeGga2/+hTf+H9ZN2HHeTj6srDh2MHJY4cMzsAcyKfv3WZ2rvd26i4qMuGOzSwDyG0hDEueF cJnT+IsgK4UVMcWiUWYPGYuTAQxKRVLy7p/Y2USoW36RDCDD4fHm5wKM78MqLuvO1lceQO5JojopM 3UHhLpX8gDV4QeW6DUNa1eJaT4aG6lts2Hvv4ZxYkBQ7iTFpgLxE/nr5LGYwXC/F0Fj+VF7F+pUEB LkDojwEg==; Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lZVFc-00DWjy-GC for linux-arm-kernel@lists.infradead.org; Thu, 22 Apr 2021 09:03:58 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619082234; h=from:from: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=tBPIqE9re75l34eoDms0OtxOrGa4ChUZqthAcy2zOrM=; b=eAnkxA79jnWDfCIe3QAxugWykP2KoLXAoDAwSK2zzaByVxzPTZPuTh5ykVJp1oggUXcSmi TuR7gPs/neKNpisQgx0oujefKkjJdbFblr3w0m/d4EGoisQYTqo4cS4KFDBeUyTx+DyB0l booD/WuZaMzxKH4y/GScFJcyciN595c= Received: from mail-ej1-f72.google.com (mail-ej1-f72.google.com [209.85.218.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-470-0LHqfkZpPUWY81GyWv-NLw-1; Thu, 22 Apr 2021 05:03:52 -0400 X-MC-Unique: 0LHqfkZpPUWY81GyWv-NLw-1 Received: by mail-ej1-f72.google.com with SMTP id i10-20020a1709067a4ab029037c5dba8400so7004126ejo.8 for ; Thu, 22 Apr 2021 02:03:52 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:cc:references:from:organization:subject :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=tBPIqE9re75l34eoDms0OtxOrGa4ChUZqthAcy2zOrM=; b=CQY/STIpxtBIkEHh4EbpzLBsoyUYe+r/hXC+N0myBreeL7KvSu8uHWR44iQ9dFvSHR eqjSQLwlkkOOF80sLHjg6YBGCg1Dr2dAuSHdxPEcqXZh8m8Qbk7sHEYRIFkhRZQLjBSw SS4B+9GH+tsxzLoTJWXn+ccbk5f4w2sq0t6bP1jdlPWvcq5GyYgPUNs1XimJhi5py/AR P3EyUBMzz5wA4rENmFxmSQ/HAvqGejFDYdH+dr1qaVM86xwQEHrlNgzZcQ8nN7Yd4bw4 ZcH+qMEfi1/Ztcg8TV/i1flGWZ+MOXUa7tM3kofpbdtnWV3jR4d/bb7XWP1iKoJxkO/N URvw== X-Gm-Message-State: AOAM533n1xqY0Jx1bw9abFzTHpMWfCF+K2ZFRLlxJdcp1clHa45B8JIk WgIq8iMLXmzu66kTgecEAg7PmqDejF2nhtiAeICfNVFWbGb+rAAU00ZpPkjqhnv4wYKNwjYiCjA gyRv+8i5SZkUrvrM+OGeyCVWUvw7gICigT3k= X-Received: by 2002:a17:906:6789:: with SMTP id q9mr2284319ejp.295.1619082231195; Thu, 22 Apr 2021 02:03:51 -0700 (PDT) X-Google-Smtp-Source: ABdhPJy0ZIkGyQ8YQhVpysHUbBH/txixJO1HYTzsDCKxnSGD6bzgdJdqq8evOkJVZOlVMTKlCWdCMQ== X-Received: by 2002:a17:906:6789:: with SMTP id q9mr2284296ejp.295.1619082230970; Thu, 22 Apr 2021 02:03:50 -0700 (PDT) Received: from [192.168.3.132] (p4ff23eb0.dip0.t-ipconnect.de. [79.242.62.176]) by smtp.gmail.com with ESMTPSA id n14sm1399947ejy.90.2021.04.22.02.03.50 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 22 Apr 2021 02:03:50 -0700 (PDT) To: Anshuman Khandual , linux-mm@kvack.org Cc: rppt@kernel.org, akpm@linux-foundation.org, Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20210422061902.21614-1-rppt@kernel.org> <1619077823-3819-1-git-send-email-anshuman.khandual@arm.com> From: David Hildenbrand Organization: Red Hat Subject: Re: [RFC V2] mm: Enable generic pfn_valid() to handle early sections with memmap holes Message-ID: Date: Thu, 22 Apr 2021 11:03:50 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <1619077823-3819-1-git-send-email-anshuman.khandual@arm.com> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=david@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210422_020356_649131_DB8C664B X-CRM114-Status: GOOD ( 43.62 ) 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-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 22.04.21 09:50, Anshuman Khandual wrote: > Platforms like arm and arm64 have redefined pfn_valid() because their early > memory sections might have contained memmap holes after freeing parts of it > during boot, which should be skipped while validating a pfn for struct page > backing. This scenario on certain platforms where memmap is not continuous, > could be captured with a new option CONFIG_HAVE_EARLY_SECTION_MEMMAP_HOLES. > Then the generic pfn_valid() can be improved to accommodate such platforms. > This reduces overall code footprint and also improves maintainability. > > free_unused_memmap() and pfn_to_online_page() have been updated to include > such cases. This also exports memblock_is_memory() for all drivers that use > pfn_valid() but lack required visibility. After the new config is in place, > drop CONFIG_HAVE_ARCH_PFN_VALID from arm64 platforms. > > Cc: Catalin Marinas > Cc: Will Deacon > Cc: Andrew Morton > Cc: Mike Rapoport > Cc: David Hildenbrand > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-kernel@vger.kernel.org > Cc: linux-mm@kvack.org > Suggested-by: David Hildenbrand > Signed-off-by: Anshuman Khandual > --- > This patch applies on the latest mainline kernel after Mike's series > regarding arm64 based pfn_valid(). > > https://lore.kernel.org/linux-mm/20210422061902.21614-1-rppt@kernel.org/T/#t > > Changes in RFC V2: > > - Dropped support for arm (32 bit) > - Replaced memblock_is_map_memory() check with memblock_is_memory() > - MEMBLOCK_NOMAP memory are no longer skipped for pfn_valid() > - Updated pfn_to_online_page() per David > - Updated free_unused_memmap() to preserve existing semantics per Mike > - Exported memblock_is_memory() instead of memblock_is_map_memory() > > Changes in RFC V1: > > - https://patchwork.kernel.org/project/linux-mm/patch/1615174073-10520-1-git-send-email-anshuman.khandual@arm.com/ > > arch/arm64/Kconfig | 2 +- > arch/arm64/include/asm/page.h | 1 - > arch/arm64/mm/init.c | 41 ----------------------------------- > include/linux/mmzone.h | 18 ++++++++++++++- > mm/Kconfig | 9 ++++++++ > mm/memblock.c | 8 +++++-- > mm/memory_hotplug.c | 5 +++++ > 7 files changed, 38 insertions(+), 46 deletions(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index b4a9b493ce72..4cdc3570ffa9 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -144,7 +144,6 @@ config ARM64 > select HAVE_ARCH_KGDB > select HAVE_ARCH_MMAP_RND_BITS > select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT > - select HAVE_ARCH_PFN_VALID > select HAVE_ARCH_PREL32_RELOCATIONS > select HAVE_ARCH_SECCOMP_FILTER > select HAVE_ARCH_STACKLEAK > @@ -167,6 +166,7 @@ config ARM64 > if $(cc-option,-fpatchable-function-entry=2) > select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \ > if DYNAMIC_FTRACE_WITH_REGS > + select HAVE_EARLY_SECTION_MEMMAP_HOLES > select HAVE_EFFICIENT_UNALIGNED_ACCESS > select HAVE_FAST_GUP > select HAVE_FTRACE_MCOUNT_RECORD > diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h > index 75ddfe671393..fcbef3eec4b2 100644 > --- a/arch/arm64/include/asm/page.h > +++ b/arch/arm64/include/asm/page.h > @@ -37,7 +37,6 @@ void copy_highpage(struct page *to, struct page *from); > > typedef struct page *pgtable_t; > > -int pfn_valid(unsigned long pfn); > int pfn_is_map_memory(unsigned long pfn); > > #include > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > index f431b38d0837..5731a11550d8 100644 > --- a/arch/arm64/mm/init.c > +++ b/arch/arm64/mm/init.c > @@ -217,47 +217,6 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max) > free_area_init(max_zone_pfns); > } > > -int pfn_valid(unsigned long pfn) > -{ > - phys_addr_t addr = PFN_PHYS(pfn); > - > - /* > - * Ensure the upper PAGE_SHIFT bits are clear in the > - * pfn. Else it might lead to false positives when > - * some of the upper bits are set, but the lower bits > - * match a valid pfn. > - */ > - if (PHYS_PFN(addr) != pfn) > - return 0; > - > -#ifdef CONFIG_SPARSEMEM > -{ > - struct mem_section *ms; > - > - if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) > - return 0; > - > - ms = __pfn_to_section(pfn); > - if (!valid_section(ms)) > - return 0; > - > - /* > - * ZONE_DEVICE memory does not have the memblock entries. > - * memblock_is_memory() check for ZONE_DEVICE based > - * addresses will always fail. Even the normal hotplugged > - * memory will never have MEMBLOCK_NOMAP flag set in their > - * memblock entries. Skip memblock search for all non early > - * memory sections covering all of hotplug memory including > - * both normal and ZONE_DEVICE based. > - */ > - if (!early_section(ms)) > - return pfn_section_valid(ms, pfn); > -} > -#endif > - return memblock_is_memory(addr); > -} > -EXPORT_SYMBOL(pfn_valid); > - > int pfn_is_map_memory(unsigned long pfn) > { > phys_addr_t addr = PFN_PHYS(pfn); > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > index 961f0eeefb62..18bf71665211 100644 > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -1421,10 +1421,22 @@ static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn) > * > * Return: 1 for PFNs that have memory map entries and 0 otherwise > */ > +bool memblock_is_memory(phys_addr_t addr); > + > static inline int pfn_valid(unsigned long pfn) > { > + phys_addr_t addr = PFN_PHYS(pfn); > struct mem_section *ms; > > + /* > + * Ensure the upper PAGE_SHIFT bits are clear in the > + * pfn. Else it might lead to false positives when > + * some of the upper bits are set, but the lower bits > + * match a valid pfn. > + */ > + if (PHYS_PFN(addr) != pfn) > + return 0; > + > if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) > return 0; > ms = __nr_to_section(pfn_to_section_nr(pfn)); > @@ -1434,7 +1446,11 @@ static inline int pfn_valid(unsigned long pfn) > * Traditionally early sections always returned pfn_valid() for > * the entire section-sized span. > */ > - return early_section(ms) || pfn_section_valid(ms, pfn); > + if (early_section(ms)) > + return IS_ENABLED(CONFIG_HAVE_EARLY_SECTION_MEMMAP_HOLES) ? > + memblock_is_memory(pfn << PAGE_SHIFT) : 1; > + > + return pfn_section_valid(ms, pfn); > } > #endif > > diff --git a/mm/Kconfig b/mm/Kconfig > index 24c045b24b95..db7128111874 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -135,6 +135,15 @@ config HAVE_FAST_GUP > config ARCH_KEEP_MEMBLOCK > bool > > +config HAVE_EARLY_SECTION_MEMMAP_HOLES > + depends on ARCH_KEEP_MEMBLOCK && SPARSEMEM_VMEMMAP > + def_bool n > + help > + Early sections on certain platforms might have some memory ranges that > + are not backed with struct page mappings. When subscribed, this option > + enables special handling for those memory ranges in certain situations > + such as pfn_valid(). > + > # Keep arch NUMA mapping infrastructure post-init. > config NUMA_KEEP_MEMINFO > bool > diff --git a/mm/memblock.c b/mm/memblock.c > index 3abf2c3fea7f..93f8a9c8428d 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -1740,6 +1740,7 @@ bool __init_memblock memblock_is_memory(phys_addr_t addr) > { > return memblock_search(&memblock.memory, addr) != -1; > } > +EXPORT_SYMBOL(memblock_is_memory); > > bool __init_memblock memblock_is_map_memory(phys_addr_t addr) > { > @@ -1931,8 +1932,11 @@ static void __init free_unused_memmap(void) > unsigned long start, end, prev_end = 0; > int i; > > - if (!IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID) || > - 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; > > /* > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index 0cdbbfbc5757..8c78b6a3d888 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -309,6 +309,11 @@ struct page *pfn_to_online_page(unsigned long pfn) > * Save some code text when online_section() + > * pfn_section_valid() are sufficient. > */ > + if (IS_ENABLED(CONFIG_HAVE_EARLY_SECTION_MEMMAP_HOLES)) { > + if (early_section(ms) && !memblock_is_memory(PFN_PHYS(pfn))) > + return NULL; > + } > + > if (IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID) && !pfn_valid(pfn)) > return NULL; > > What about doing one step at a time and switching only over to generic pfn_valid() in case of CONFIG_SPARSEMEM? (meaning: freeing the memmap only with !CONFIG_SPARSEMEM) IOW, avoiding having to adjust generic pfn_valid()/pfn_to_online_page() at all. Am i missing something or should that be possible? -- Thanks, David / dhildenb _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel