On 11/30/2012 11:15 AM, Yasuaki Ishimatsu wrote: > Hi Jiang, > >> >> For the first issue, I think we could automatically convert pages >> from movable zones into normal zones. Congyan from Fujitsu has provided >> a patchset to manually convert pages from movable zones into normal zones, >> I think we could extend that mechanism to automatically convert when >> normal zones are under pressure by hooking into the slow page allocation >> path. >> >> We rely on hardware features to solve the second and third issues. >> Some new platforms provide a new RAS feature called "hardware memory >> migration", which transparent migrate memory from one memory device >> to another. With hardware memory migration, we could configure one >> memory device on a NUMA node to host normal zone, and the other memory >> devices to host movable zone. By this configuration, it won't cause >> performance drop because each NUMA node still has local normal zone. >> When trying to remove a memory device hosting normal zone, we just >> need to find another spare memory device and use hardware memory migration >> to transparently migrate memory content to the spare one. The drawback >> is we have strong dependency on hardware features so it's not a common >> solution for all architectures. > > I agree with you. If BIOS and hardware support memory hotplug, OS should > use them. But if OS cannot use them, we need to solve in OS. I think > that our proposal which used ZONE_MOVABLE is first step for supporting > memory hotplug. Hi Yasuaki, It's true, we should start with first step then improve it. Regards! Gerry -- 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>