Messages in this thread Patch in this message | | | From | Robin Murphy <> | Subject | [PATCH] arm64: Add memory hotplug support | Date | Mon, 10 Dec 2018 15:29:01 +0000 |
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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 <robin.murphy@arm.com> ---
Looks like I'm not going to have the whole pte_devmap story figured out in time to land any ZONE_DEVICE support this cycle, but since this patch also stands alone as a complete feature (and has ended up remarkably simple and self-contained), I hope we might consider getting it merged on its own merit.
Robin.
arch/arm64/Kconfig | 3 +++ arch/arm64/mm/init.c | 8 ++++++++ arch/arm64/mm/mmu.c | 12 ++++++++++++ arch/arm64/mm/numa.c | 10 ++++++++++ 4 files changed, 33 insertions(+)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 6d2b25f51bb3..7b855ae45747 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 2983e0fc1786..82e0b08f2e31 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 e1b2d58a311a..22379a74d289 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1044,3 +1044,15 @@ 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) +{ + __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), + size, PAGE_KERNEL, pgd_pgtable_alloc, 0); + + 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
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