On Wed 19-12-18 13:56:35, Wei Yang wrote: > On Wed, Dec 19, 2018 at 02:40:56PM +0100, Michal Hocko wrote: > >On Wed 19-12-18 13:29:34, Wei Yang wrote: [...] > >> As the comment mentioned, in current implementation the range must be in > >> one zone. > > > >I do not see anything like that documented for set_migratetype_isolate. > > The comment is not on set_migratetype_isolate, but for its two > (grandparent) callers: > > __offline_pages > alloc_contig_range But those are consumers while the main api here is start_isolate_page_range. What happens if we grow a new user? Go over the same problems? See the difference? Please try to look at these things from a higher level. We really do not want micro optimise on behalf of a sane API. Unless there is a very good reason to do that - e.g. when the performance difference is really huge. -- Michal Hocko SUSE Labs
