On Mon, May 02, 2011 at 02:25:04PM -0700, Dave Hansen wrote: > On Mon, 2011-05-02 at 23:19 +0200, Daniel Kiper wrote: > > Memory hotplug code strictly depends on CONFIG_SPARSEMEM. > > It means that code depending on CONFIG_FLATMEM in online_page() > > is never compiled. Remove it because it is not needed anymore. > > It's subtle, but I don't think that's true. We had another hotplug mode > for x86_64 before folks were comfortable turning SPARSEMEM on for the > whole architecture. It was quite possible to have memory hotplug > without sparsemem in that case. I think Keith Mannthey did some of that > code if I remember right. > > But, I'm not sure how much of that stayed in distros versus made it > upstream. In any case, you might want to chase down the > X86_64_ACPI_NUMA bit to make sure it can't be used with FLATMEM ever. > > config MEMORY_HOTPLUG > bool "Allow for memory hot-add" > depends on SPARSEMEM || X86_64_ACPI_NUMA > depends on HOTPLUG && ARCH_ENABLE_MEMORY_HOTPLUG > depends on (IA64 || X86 || PPC_BOOK3S_64 || SUPERH || S390) IIRC some time ago it was possible to enable memory hotplug with CONFIG_FLATMEM. That is why I looked for any dependencies of memory hoplug code on CONFIG_FLATMEM in current Linux Kernel source. I could not find anything and that is why I published this patch. However, maybe I missed something. Daniel -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>