On Mon 28-09-20 20:21:10, David Hildenbrand wrote: > As we no longer shuffle via generic_online_page() and when undoing > isolation, we can simplify the comment. > > We now effectively shuffle only once (properly) when onlining new > memory. > > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Cc: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx> > Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> > Cc: Michal Hocko <mhocko@xxxxxxxxxx> > Cc: Dave Hansen <dave.hansen@xxxxxxxxx> > Cc: Vlastimil Babka <vbabka@xxxxxxx> > Cc: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx> > Cc: Oscar Salvador <osalvador@xxxxxxx> > Cc: Mike Rapoport <rppt@xxxxxxxxxx> > Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> > --- > mm/memory_hotplug.c | 11 ++++------- > 1 file changed, 4 insertions(+), 7 deletions(-) > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index 9db80ee29caa..c589bd8801bb 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -859,13 +859,10 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, > undo_isolate_page_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE); > > /* > - * When exposing larger, physically contiguous memory areas to the > - * buddy, shuffling in the buddy (when freeing onlined pages, putting > - * them either to the head or the tail of the freelist) is only helpful > - * for maintaining the shuffle, but not for creating the initial > - * shuffle. Shuffle the whole zone to make sure the just onlined pages > - * are properly distributed across the whole freelist. Make sure to > - * shuffle once pageblocks are no longer isolated. > + * Freshly onlined pages aren't shuffled (e.g., all pages are placed to > + * the tail of the freelist when undoing isolation). Shuffle the whole > + * zone to make sure the just onlined pages are properly distributed > + * across the whole freelist - to create an initial shuffle. > */ > shuffle_zone(zone); > > -- > 2.26.2 -- Michal Hocko SUSE Labs
