On Tue 11-08-20 10:29:24, David Hildenbrand wrote: [...] > I was wondering if we should rather set all pageblocks to > MIGRATE_ISOLATE in online_pages() before doing the online_pages_range() > call, and do undo_isolate_page_range() after onlining is done. > > move_pfn_range_to_zone()->memmap_init_zone() marks all pageblocks > MIGRATE_MOVABLE, and as that function is used also during boot, we could > supply a parameter to configure this. > > This would prevent another race from happening: Having pages exposed to > the buddy ready for allocation in online_pages_range() before the > sections are marked online. > > This would avoid any pages from getting allocated before we're > completely done onlining. This sounds like a reasonable idea to me. > We would need MIGRATE_ISOLATE/CONFIG_MEMORY_ISOLATION also for > CONFIG_MEMORY_HOTPLUG. We already do depend on the memory isolation in the hotremove. Doing the same for hotplug in general makes sense as well. Thanks! -- Michal Hocko SUSE Labs
