On Thu, 2010-03-11 at 19:18 +0800, Prarit Bhargava wrote: > > ykzhao wrote: > > On Thu, 2010-03-11 at 10:18 +0800, Prarit Bhargava wrote: > > > >>> Yes. The nehalem processor has the integrated memory controller. But it > >>> is not required that the hot-added memory should be onlined before > >>> bringing up CPU. > >>> I do the following memory-hotplug test on one Machine. > >>> a. Before hot plugging memory, four CPUs socket are installed and > >>> all the logical CPU are brought up. (Only one node has the memory) > >>> b. The memory is hot-plugged and then the memory is onlined so that > >>> it can be accessed by the system. > >>> > >>> In the above testing case the CPU is brought up before onlining the > >>> hot-added memory. And the test shows that it can work well. > >>> > >>> > >> That doesn't work when you have multiple nodes AFAICT. The cpus do not > >> come into service because of a lack of memory on the node.... per node > >> allocations will fail. > >> > > > > In the test the system has multiple nodes. The reason is that the cpu > > without memory can turn to other node and allocate the memory. > > > > > >> Just curious, exactly what did you test with? 2.6.33 (or newer)? > >> > > > > I test it on 2.6.32 kernel. > > > > 2.6.32 doesn't work with memory and cpu. > 2.6.33 doesn't work with memory and cpu. I don't test the scenario of both cpu and memory hot-plugging. What I mean is that the 2.6.32 kernel can work if only memory is hot-plugged (The cpu is already brought-up in the boot phase). > > Other patches (which have been posted upstream) are required. > > > I'll try to dig up the patches and you can retest. > > I will try a memory-free cpu add as well to see if that works... but the > performance hit due to the off-node allocations probably doesn't make it > worthwhile. > > > P. > > > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
