Re: [RFC v3] sched/topology: fix kernel crash when a CPU is hotplugged in a memoryless node

2019-03-05 Thread Peter Zijlstra
On Mon, Mar 04, 2019 at 08:59:52PM +0100, Laurent Vivier wrote: > This happens because initially powerpc code computes > sched_domains_numa_masks of offline nodes as if they were merged with > node 0 (because firmware doesn't provide the distance information for > memoryless/cpuless nodes): > >

[RFC v3] sched/topology: fix kernel crash when a CPU is hotplugged in a memoryless node

2019-03-04 Thread Laurent Vivier
When we hotplug a CPU in a memoryless/cpuless node, the kernel crashes when it rebuilds the sched_domains data. I reproduce this problem on POWER and with a pseries VM, with the following QEMU parameters: -machine pseries -enable-kvm -m 8192 \ -smp 2,maxcpus=8,sockets=4,cores=2,threads=1 \