Memory-hotplug codes for x86_64 have been implemented by patchset: https://lkml.org/lkml/2013/1/9/124 While other platforms haven't been completely implemented yet. If we enable both CONFIG_MEMORY_HOTPLUG_SPARSE and CONFIG_SPARSEMEM_VMEMMAP, register_page_bootmem_info_node() may be buggy, which is a hotplug generic function but falling back to call platform related function register_page_bootmem_memmap(). Other platforms such as powerpc it's not implemented, so on such platforms, revert them to empty as they were before. It's implemented by adding a new Kconfig option named CONFIG_HAVE_BOOTMEM_INFO_NODE, which will be automatically selected by supported archs(currently only on x86_64). Reported-by: Michal Hocko <mhocko@xxxxxxx> Signed-off-by: Lin Feng <linfeng@xxxxxxxxxxxxxx> --- ChangeLog v1->v2: - Add a Kconfig option named HAVE_BOOTMEM_INFO_NODE suggested by Michal, which will be automatically selected by supported archs(currently only on x86_64). --- mm/Kconfig | 8 ++++++++ mm/memory_hotplug.c | 7 +++++++ 2 files changed, 15 insertions(+), 0 deletions(-) diff --git a/mm/Kconfig b/mm/Kconfig index 278e3ab..f8c5799 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -162,10 +162,18 @@ config MOVABLE_NODE Say Y here if you want to hotplug a whole node. Say N here if you want kernel to use memory on all nodes evenly. +# +# Only be set on architectures that have completely implemented memory hotplug +# feature. If you are not sure, don't touch it. +# +config HAVE_BOOTMEM_INFO_NODE + def_bool n + # eventually, we can have this option just 'select SPARSEMEM' config MEMORY_HOTPLUG bool "Allow for memory hot-add" select MEMORY_ISOLATION + select HAVE_BOOTMEM_INFO_NODE if X86_64 depends on SPARSEMEM || X86_64_ACPI_NUMA depends on HOTPLUG && ARCH_ENABLE_MEMORY_HOTPLUG depends on (IA64 || X86 || PPC_BOOK3S_64 || SUPERH || S390) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 8aa2b56..ef7a5c8 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -189,6 +189,7 @@ static void register_page_bootmem_info_section(unsigned long start_pfn) } #endif +#ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE void register_page_bootmem_info_node(struct pglist_data *pgdat) { unsigned long i, pfn, end_pfn, nr_pages; @@ -230,6 +231,12 @@ void register_page_bootmem_info_node(struct pglist_data *pgdat) register_page_bootmem_info_section(pfn); } } +#else +void register_page_bootmem_info_node(struct pglist_data *pgdat) +{ + /* TODO */ +} +#endif static void grow_zone_span(struct zone *zone, unsigned long start_pfn, unsigned long end_pfn) -- 1.7.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>