On Mon 21-10-19 17:39:36, David Hildenbrand wrote: > On 21.10.19 16:43, Michal Hocko wrote: [...] > > We still set PageReserved before onlining pages and that one should be > > good to go as well (memmap_init_zone). > > Thanks! > > memmap_init_zone() is called when onlining memory. There, set all pages to > reserved right now (on context == MEMMAP_HOTPLUG). We clear PG_reserved when > onlining a page to the buddy (e.g., generic_online_page). If we would online > a memory block with holes, we would want to keep all such pages > (!pfn_valid()) set to reserved. Also, there might be other side effects. Isn't it sufficient to have those pages in a poisoned state? They are not onlined so their state is basically undefined anyway. I do not see how PageReserved makes this any better. Also is the hole inside a hotplugable memory something we really have to care about. Has anybody actually seen a platform to require that? -- Michal Hocko SUSE Labs
