On Tue 07-11-17 09:20:47, Vlastimil Babka wrote: > On 11/06/2017 07:32 PM, Michal Hocko wrote: > > On Mon 06-11-17 20:13:36, Maxim Levitsky wrote: > >> Yes, I tested git head from mainline and few kernels from ubuntu repos > >> since I was lazy to compile them too. > > > > OK, so this hasn't worked realiably as I've suspected. > > > >> Do you have an idea what can I do about this issue? Do you think its > >> feasable to fix this? > > > > Well, I think that giga pages need quite some love to be usable > > reliably. The current implementation is more towards "make it work if > > there is enough unused memory". > > > >> And if not using moveable zone, how would it even be possible to have > >> guaranreed allocation of 1g pages > > > > Having a guaranteed giga pages is something the kernel is not yet ready > > to offer. Abusing zone movable might look like the right direction > > but that is not really the case until we make sure those pages are > > migratable. > > Migratable where? It's very unlikely you will be able to migrate them > away from a movable zone to a normal zone. So the use case is migration > between hotplugable nodes, so one of them can be removed? Yes, basically what we do for hugetlb pages normally. Smaller hugetlb pages are more likely to succeed, though. > That would > probably be an improvement (even if you could not guarantee to offline > all hotplugable nodes at once without admin intervention removing those > giga pages). Right now the only scenario where giga pages are compatible > with hot-remove is to put them on the already-limited non-removable node > 0... Yes, we will never be perfect, but I can see why people want to allocate from movable zones so we definitely should work on making giga pages more robust. The current state makes cry... -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
