Messages in this thread | | | Date | Mon, 05 Oct 2009 11:09:59 -0700 | From | Yinghai Lu <> | Subject | Re: [PATCH] x86: use near online node instead of round bin for numa |
| |
Andi Kleen wrote: > Yinghai Lu <yinghai@kernel.org> writes: > >> cpu to node mapping is set in following sequence: >> 1. numa_init_array: set up roundbin from cpu to online node >> 2. init_cpu_to_node: set that according to apicid_to_node[] according to srat >> only handle that node is online, and leave other cpu on node >> without ram (aka not online) to still round-bin >> 3. later srat_detect_node for intel/amd, will use first_online node or near by >> node. >> >> problem is that setup_per_cpu_areas() is called between 2 and 3. the per_cpu >> for cpu on node with ram is on different node. and could put that on node with >> two hops away. >> >> so try add find_near_online_node() and call int init_cpu_to_node() > > This fallback case should not really happen anyways, unless the BIOS is buggy > (in this case it might better to completely reject the SRAT because > more might be wrong). SRAT is right, and some node has no ram installed. > > Do you have a system where this is needed?
sure.
YH
| |