On Wed 24-06-20 10:41:18, David Hildenbrand wrote: [...] > But nothing actually breaks .... because *drummroll* we use huge pages in the > vmemmap, > so the partial depopulate will not actually depopulate anything here. Huge > page is 2M, > the memmap of 128MB sections is exactly 2MB == one hugepages. Trying to > depopulate a > fraction (e.g., 16MB) of that won't do anything. > > > Now, forcing a CPU without hugepages - PSE (QEMU: "-cpu host,pse=off)", I can > trigger > via ndctl create-namespace --force --reconfig=namespace0.0 --mode=devdax > --size=16M
OK, now I am following! Thanks a lot. That is something to be mentioned in the changelog. Small pages might be used if the hotplug happens on a system with fragmented memory so this is something we do care about. Thanks a lot David! -- Michal Hocko SUSE Labs
