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=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 450A9C43461 for ; Thu, 22 Apr 2021 09:43:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0D6CE600EF for ; Thu, 22 Apr 2021 09:43:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235613AbhDVJnn (ORCPT ); Thu, 22 Apr 2021 05:43:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:58000 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230365AbhDVJnk (ORCPT ); Thu, 22 Apr 2021 05:43:40 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 29F0C6141C; Thu, 22 Apr 2021 09:43:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1619084586; bh=3+PtUaQlS5Mbsu2aYYPHGVbUTy0AdZ2dMqSLbhefucM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ExgH1A77bzPQfp+leFiv3+CZ6n0aaYYarPAfj4KWbr4UGKchAFadsT+pFZpzvVv7i BZdIaPGBCit9qqGpNx4Mg+WncHnHp4MZQwr98zsLqOVddy57UaP/1KgrHigY14qFB4 FBFmx5v9dpVVM948kR60OHkyASCqKgKSzyh+z/l/YOqOyORGZXxrQY9OJ8xiKNeYWc e2J2MXW+qnwiZg07dhlFWjECJiOU2V+fHTSgve38RIhBgj/gWM9RRRBCz7cVkwMS21 lL31iXr52CUuqsTdNuRr3tVbc7AyRNQOKoqUZ16EvnWyiBsxfqWhcHP4yzhFbmnWCV +6kY3+s6yo7JA== Date: Thu, 22 Apr 2021 12:42:58 +0300 From: Mike Rapoport To: David Hildenbrand Cc: Anshuman Khandual , linux-mm@kvack.org, akpm@linux-foundation.org, Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [RFC V2] mm: Enable generic pfn_valid() to handle early sections with memmap holes Message-ID: References: <20210422061902.21614-1-rppt@kernel.org> <1619077823-3819-1-git-send-email-anshuman.khandual@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 22, 2021 at 11:03:50AM +0200, David Hildenbrand wrote: > 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) The "generic" pfn_valid() is only available with CONFIG_SPARSEMEM. With FLATMEM it's wild west: $ git grep -w "define pfn_valid" arch/*/include/asm/ | wc -l 22 This would actually mean that we still need arm64::pfn_valid() for the FLATMEM case. > IOW, avoiding having to adjust generic pfn_valid()/pfn_to_online_page() at > all. Am i missing something or should that be possible? We are back again to the question "should arm64 free its memmap". If the answer is no, we don't need arm64::pfn_valid() for SPARSEMEM at all. If the answer is yes, Anshuman's patch is way better than a custom pfn_valid(). -- Sincerely yours, Mike. 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=-14.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 8EA5DC433ED for ; Thu, 22 Apr 2021 09:45:57 +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 CB19E613C0 for ; Thu, 22 Apr 2021 09:45:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CB19E613C0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=n514nu13psvD+H6Bjjh4628HCgPioV6cp6YFfoOT/fA=; b=OX1ViDj5jq3R00UnaFLlid0eV 4S7McK1dbC6kshsqs9SxxfAFm7KK3A3RlYkgSUmpouf52dEApjKFIVnZcJi7Sl03KiHRMD1W/Cmh6 NxZaAcBsjyUTRHZcHrbDw84Dn4qLT136Bf9WfkNMZQy6M+7JxZD3tJ7ag117faWLMpmZrvXh46CMP 8QkWU0/1t87KtzGxNLxmAhLyAwMVz0Q/HBJCj2/WXkjfCuP8MhpiMJzKCGws1cv41+a5H5pyrHJnf yPxrVtELqAi0kXhRlwevSxc40OFINyVGd1NplP3p5EBjQgY2WxfYZb9Svs8G0/+X4RZ1wxTjDai+n 5zrssPJBg==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lZVrg-00GNYG-4w; Thu, 22 Apr 2021 09:43:16 +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 1lZVra-00GNXx-1v for linux-arm-kernel@desiato.infradead.org; Thu, 22 Apr 2021 09:43:10 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=iCJUkWrWX66JlBM654zjIJfj25geXme6cm94u/my7jE=; b=oercUXVeSJeNGtrvtHtOdFPsMV KSj3MJqwxItg0n03STK1XVo8jQDURzVoeJzH50sadE7tPvIni2/7Kixetm6rfTxoKX6ZsbtPy8+ZQ NaazQ1P38jQHruBrIRscJOUKcBspksHPX0JnvbJ+h30hcAESEspZJc6M3KjDMn747fvkPtJypr/Ea morDL1DLt0oGjk+YiDP0zSpLoZ+UgT1FaFS0+c/qiseyemhcGcUR3uJZfTBTXDyR1smsvnL+tZnmc ovgEL3h/ZkBPsjQ+ZvxQCe7PNojagijYV34zEeE3L0DNzLPHWamKGN1ETbw6hX5LDRda7vY3oXYx0 mLcHxJeA==; Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lZVrW-00DYHS-P1 for linux-arm-kernel@lists.infradead.org; Thu, 22 Apr 2021 09:43:08 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 29F0C6141C; Thu, 22 Apr 2021 09:43:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1619084586; bh=3+PtUaQlS5Mbsu2aYYPHGVbUTy0AdZ2dMqSLbhefucM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ExgH1A77bzPQfp+leFiv3+CZ6n0aaYYarPAfj4KWbr4UGKchAFadsT+pFZpzvVv7i BZdIaPGBCit9qqGpNx4Mg+WncHnHp4MZQwr98zsLqOVddy57UaP/1KgrHigY14qFB4 FBFmx5v9dpVVM948kR60OHkyASCqKgKSzyh+z/l/YOqOyORGZXxrQY9OJ8xiKNeYWc e2J2MXW+qnwiZg07dhlFWjECJiOU2V+fHTSgve38RIhBgj/gWM9RRRBCz7cVkwMS21 lL31iXr52CUuqsTdNuRr3tVbc7AyRNQOKoqUZ16EvnWyiBsxfqWhcHP4yzhFbmnWCV +6kY3+s6yo7JA== Date: Thu, 22 Apr 2021 12:42:58 +0300 From: Mike Rapoport To: David Hildenbrand Cc: Anshuman Khandual , linux-mm@kvack.org, akpm@linux-foundation.org, Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [RFC V2] mm: Enable generic pfn_valid() to handle early sections with memmap holes Message-ID: References: <20210422061902.21614-1-rppt@kernel.org> <1619077823-3819-1-git-send-email-anshuman.khandual@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210422_024306_897503_C930CA92 X-CRM114-Status: GOOD ( 47.03 ) 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 Thu, Apr 22, 2021 at 11:03:50AM +0200, David Hildenbrand wrote: > 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) The "generic" pfn_valid() is only available with CONFIG_SPARSEMEM. With FLATMEM it's wild west: $ git grep -w "define pfn_valid" arch/*/include/asm/ | wc -l 22 This would actually mean that we still need arm64::pfn_valid() for the FLATMEM case. > IOW, avoiding having to adjust generic pfn_valid()/pfn_to_online_page() at > all. Am i missing something or should that be possible? We are back again to the question "should arm64 free its memmap". If the answer is no, we don't need arm64::pfn_valid() for SPARSEMEM at all. If the answer is yes, Anshuman's patch is way better than a custom pfn_valid(). -- Sincerely yours, Mike. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel