On Mon, 1 Mar 2010, KAMEZAWA Hiroyuki wrote: > > > Well Kamesan indicated that this worked if a cpu became online. > > > > I mean in the general case. There were tons of problems all over. > > > Then, it's cpu hotplug matter, not memory hotplug. > cpu hotplug callback should prepaare > > > l3 = searchp->nodelists[node]; > BUG_ON(!l3); > > before onlined. Rather than taking care of races. > I can only speak for x86 and not the abundance of memory hotplug support that exists for powerpc, but cpu hotplug doesn't do _anything_ when a memory region that has a corresponding ACPI_SRAT_MEM_HOT_PLUGGABLE entry in the SRAT is hotadded and requires a new nodeid. That can be triggered via the acpi layer with plug and play or explicitly from the command line via CONFIG_ARCH_MEMORY_PROBE. Relying on cpu hotplug to set up nodelists in such a circumstance simply won't work. You need memory hotplug support such as in my patch. -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>