On 4/11/19 4:23 PM, Daniel Henrique Barboza wrote:
Hi, I've tested these patches again, twice, in similar setups like I tested the first version (first in a Power8, then in a Power9 server). Same results, though. Libvirt will not avoid the launch of a pseries guest, with numanode=strict, even if the numa node does not have available RAM. If I stress test the memory of the guest to force the allocation, QEMU exits with an error as soon as the memory of the host numa node is exhausted.
Yes, this is expected. I mean, by default qemu doesn't allocate memory for the guest fully. You'd have to force it:
<memoryBacking> <allocation mode='immediate'/> </memoryBacking>
If I change the numanode setting to 'preferred' and repeats the test, QEMU doesn't exit with an error - the process starts to take memory from other numa nodes. This indicates that the numanode policy is apparently being forced in the QEMU process - however, it is not forced in VM boot. I've debugged it a little and haven't found anything wrong that jumps the eye. All functions that succeeds qemuSetupCpusetMems exits out with ret = 0. Unfortunately, I don't have access to a x86 server with more than one NUMA node to compare results. Since I can't say for sure if what I'm seeing is an exclusive pseries behavior, I see no problem into pushing this series upstream if it makes sense for x86. We can debug/fix the Power side later.
I bet that if you force the allocation then the domain will be unable to boot.
Thanks for the testing! Michal -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
