On Wed 07-11-18 08:55:26, osalvador wrote: > On Wed, 2018-11-07 at 08:35 +0100, Michal Hocko wrote: > > On Wed 07-11-18 07:35:18, Balbir Singh wrote: > > > The check seems to be quite aggressive and in a loop that iterates > > > pages, but has nothing to do with the page, did you mean to make > > > the check > > > > > > zone_idx(page_zone(page)) == ZONE_MOVABLE > > > > Does it make any difference? Can we actually encounter a page from a > > different zone here? > > AFAIK, test_pages_in_a_zone() called from offline_pages() should ensure > that the range belongs to a unique zone, so we should not encounter > pages from other zones there, right? Yes that is the case for memory hotplug. We do assume a single zone at set_migratetype_isolate where we take the zone->lock. If the contig_alloc can span multiple zones then it should check for similar. -- Michal Hocko SUSE Labs
