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 memory-hotplug supported archs(currently only on x86_64). changeLog v2->v3: 1) patch 1/2: - Rename the patch title to conform it's content. - Update memory_hotplug.h and remove the misleading TODO pointed out by Michal. 2) patch 2/2: - New added, remove unimplemented functions suggested by Michal. ChangeLog v1->v2: 1) patch 1/2: - 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). Lin Feng (1): memory-hotplug: revert register_page_bootmem_info_node() to empty when platform related code is not implemented Michal Hocko (1): memory-hotplug: cleanup: removing the arch specific functions without any implementation arch/ia64/mm/discontig.c | 5 ----- arch/powerpc/mm/init_64.c | 5 ----- arch/s390/mm/vmem.c | 6 ------ arch/sparc/mm/init_64.c | 5 ----- arch/x86/mm/init_64.c | 2 +- include/linux/memory_hotplug.h | 6 ++++++ mm/Kconfig | 8 ++++++++ mm/memory_hotplug.c | 2 ++ 8 files changed, 17 insertions(+), 22 deletions(-) -- 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>