On Mon, Aug 21, 2017 at 03:49:50PM +0200, Laurent Vivier wrote: > In wq_numa_init() a list of NUMA nodes with their list of possible CPUs > is built. > > Unfortunately, on powerpc, the Firmware is only able to provide the > node of a CPU if the CPU is present. So, in our case (possible CPU) > CPU ids are known, but as the CPU is not present, the node id is > unknown and all the unplugged CPUs are attached to node 0.
This is something powerpc needs to fix. Workqueue isn't the only one making this assumption. mm as a whole assumes that CPU <-> node mapping is stable regardless of hotplug events. Powerpc people know about the issue and AFAIK are working on it. Thanks. -- tejun
