On Wed, Dec 19, 2018 at 03:12:35PM +0100, Michal Hocko wrote: >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? I didn't intend to fight for my patch, just want to clarify current implementation :-) > >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. Well, actually I get your idea and agree with you not rely on the caller to drain the page is the proper way to handle this. Again, I just want to clarify current situation and try to find a proper way to make it better. Maybe I lost some point, while I am willing get feedback and suggestions from all of you. >-- >Michal Hocko >SUSE Labs -- Wei Yang Help you, Help me
