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 3D07CC433ED for ; Thu, 22 Apr 2021 08:29:36 +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 85485613C0 for ; Thu, 22 Apr 2021 08:29:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 85485613C0 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=/+aJWrfCTMLfhT4jS+PQgMtpe4xY4UeBP3ye3KjtRuc=; b=U3OPeISwlWwQBVr03aFFMGfOV J+wwPTIIv6VnHmHKFJ0BkA6ltZeuezdVnqNetYDZAhx/XHcGHZibgAfQtXI76fS4qe5hJ+ak9GY1A 3Q5k2bUsIk2sANPG/6NpAQynBo+h6JHiQHdciik0U3X8FBb5a9CPVyZVofzYodhFZVmQ2NGnATDq8 OzfqlGWBeDwvqKERDOw5MT3le4Cc7ff7uC7tmtXwmY1cF3nGLnWscaJq0IlKRiRYf4ZojQUxwUZCO iRRn5clG3Uw3BVtSh4PnNG0nhBrFVO5FePIKENaaTQRXEpicFRbceTzhpFKLPzPqJThU7GJvDCtD+ HpRHiyLAA==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lZUgU-00GG1y-0L; Thu, 22 Apr 2021 08:27:38 +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 1lZUgO-00GG1d-Js for linux-arm-kernel@desiato.infradead.org; Thu, 22 Apr 2021 08:27:32 +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=LpxhkvizHt2Jm9Bv8INqOocH5O9D+SplR4+u50eHTjs=; b=kVPYkOVfHT3++kf471GaC5dbTu hhOGwHuEA4NRKTK0YcMrCFLptub4+ROXIZer9AOZyylFwyDzyILzUKtoYJoKmZgQOsNgrHOlKSlx1 qfdW2K7c+yCr6ZMN3eo1Q1ZTjFgYvlNQoIHKyR3RHOYlOZr3ZQJ23YknkBr5FVz/la2nO2n2sgAOT Ky4ufDjw7Kzv1vhFOHr+BIBWd674WcDPWOg50lSw9A0HADBAywAFlU9h6idGh/ClLtbWn0fhdaAD4 HEzyO8D3V63Ho8KQSU8G8Xc+LXiNrk7rK8wP7/FC14Sxuv2rsWZ8pjM1oLKhxamq2K48wmPhVcW6M eQtOn7vw==; Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lZUgL-00DVHg-7F for linux-arm-kernel@lists.infradead.org; Thu, 22 Apr 2021 08:27:31 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0AB97613D1; Thu, 22 Apr 2021 08:27:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1619080048; bh=djXvbcABWYNDWhCh8ZYuuG9Q/PmZOmh46pGkDmxemHM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LLKujhiaxChRQYKX9BJgOxXueJ+c9oQi/VPoG+EqqfrcQrtVyCkELaP3Ke+VOzTy7 7ukMCGEKxNKfWl2Wx276g8ISS2F9jpHvDKhraEEcxtglQ3AMAPYCaqT65LtUZdXTK0 BQ/RBdI5mR1SYjTmf0sNmjMx6aOl5M06Bk9cA3w72x4BJDqxHfM4mSgWqb/9dgwP6p GZ9IbplD8ynQsWOZZmBMsQ9VsL4v2K3TU4f6xTtdZdPzo2vZhNQg+xqWz5xj9OiReK cAxPpEIq+xeMd5oE36Oce00Fmg83cXM4tQnbywIN6SKmjmgXVooJvnF+UFzrKwUz3x dqk/Mw9XsqKCg== Date: Thu, 22 Apr 2021 11:27:21 +0300 From: Mike Rapoport To: Anshuman Khandual Cc: linux-mm@kvack.org, david@redhat.com, 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: <1619077823-3819-1-git-send-email-anshuman.khandual@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210422_012729_363997_01BFEFE0 X-CRM114-Status: GOOD ( 42.21 ) 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 01:20:23PM +0530, 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; Nit: we already did addr = PFN_PHYS(pfn); a few lines above :) > + > + 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); Please make it inside #ifdef CONFIG_ARCH_MEMBLOCK > 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; Can you please add a comment that says that architecture should provide a way to detect holes in the memory map to be able to free its part? > /* > 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; > > -- > 2.20.1 > -- Sincerely yours, Mike. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel