From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi1-f200.google.com (mail-oi1-f200.google.com [209.85.167.200]) by kanga.kvack.org (Postfix) with ESMTP id BDCE68E00C9 for ; Tue, 11 Dec 2018 13:48:55 -0500 (EST) Received: by mail-oi1-f200.google.com with SMTP id u63so8142464oie.17 for ; Tue, 11 Dec 2018 10:48:55 -0800 (PST) Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com. [217.140.101.70]) by mx.google.com with ESMTP id s205si5921129oie.38.2018.12.11.10.48.54 for ; Tue, 11 Dec 2018 10:48:54 -0800 (PST) From: Robin Murphy Subject: [PATCH v2] arm64: Add memory hotplug support Date: Tue, 11 Dec 2018 18:48:48 +0000 Message-Id: <331db1485b4c8c3466217e16a1e1f05618e9bae8.1544553902.git.robin.murphy@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: will.deacon@arm.com, catalin.marinas@arm.com Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, jonathan.cameron@huawei.com, cyrilc@xilinx.com, james.morse@arm.com, anshuman.khandual@arm.com, linux-mm@kvack.org Wire up the basic support for hot-adding memory. Since memory hotplug is fairly tightly coupled to sparsemem, we tweak pfn_valid() to also cross-check the presence of a section in the manner of the generic implementation, before falling back to memblock to check for no-map regions within a present section as before. By having arch_add_memory(() create the linear mapping first, this then makes everything work in the way that __add_section() expects. We expect hotplug to be ACPI-driven, so the swapper_pg_dir updates should be safe from races by virtue of the global device hotplug lock. Signed-off-by: Robin Murphy --- v2: Handle page-mappings-only cases appropriately arch/arm64/Kconfig | 3 +++ arch/arm64/mm/init.c | 8 ++++++++ arch/arm64/mm/mmu.c | 17 +++++++++++++++++ arch/arm64/mm/numa.c | 10 ++++++++++ 4 files changed, 38 insertions(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 4dbef530cf58..be423fda5cec 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -261,6 +261,9 @@ config ZONE_DMA32 config HAVE_GENERIC_GUP def_bool y +config ARCH_ENABLE_MEMORY_HOTPLUG + def_bool y + config SMP def_bool y diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 6cde00554e9b..4bfe0fc9edac 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -291,6 +291,14 @@ int pfn_valid(unsigned long pfn) if ((addr >> PAGE_SHIFT) != pfn) return 0; + +#ifdef CONFIG_SPARSEMEM + if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) + return 0; + + if (!valid_section(__nr_to_section(pfn_to_section_nr(pfn)))) + return 0; +#endif return memblock_is_map_memory(addr); } EXPORT_SYMBOL(pfn_valid); diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 674c409a8ce4..da513a1facf4 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1046,3 +1046,20 @@ int pud_free_pmd_page(pud_t *pudp, unsigned long addr) pmd_free(NULL, table); return 1; } + +#ifdef CONFIG_MEMORY_HOTPLUG +int arch_add_memory(int nid, u64 start, u64 size, struct vmem_altmap *altmap, + bool want_memblock) +{ + int flags = 0; + + if (rodata_full || debug_pagealloc_enabled()) + flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; + + __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), + size, PAGE_KERNEL, pgd_pgtable_alloc, flags); + + return __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, + altmap, want_memblock); +} +#endif diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c index 27a31efd9e8e..ae34e3a1cef1 100644 --- a/arch/arm64/mm/numa.c +++ b/arch/arm64/mm/numa.c @@ -466,3 +466,13 @@ void __init arm64_numa_init(void) numa_init(dummy_numa_init); } + +/* + * We hope that we will be hotplugging memory on nodes we already know about, + * such that acpi_get_node() succeeds and we never fall back to this... + */ +int memory_add_physaddr_to_nid(u64 addr) +{ + pr_warn("Unknown node for memory at 0x%llx, assuming node 0\n", addr); + return 0; +} -- 2.19.1.dirty