mm/memory_hotplug: simplify page onlining

We don't allow to offline memory with holes, all boot memory is online,
and all hotplugged memory cannot have holes.

We can now simplify onlining of pages.  As we only allow to online/offline
full sections and sections always span full MAX_ORDER_NR_PAGES, we can
just process MAX_ORDER - 1 pages without further special handling.

The number of onlined pages simply corresponds to the number of pages we
were requested to online.

While at it, refine the comment regarding the callback not exposing all
pages to the buddy.

Signed-off-by: David Hildenbrand <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Oscar Salvador <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Wei Yang <[email protected]>
Cc: Baoquan He <[email protected]>
Cc: Pankaj Gupta <[email protected]>
Cc: Charan Teja Reddy <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: Logan Gunthorpe <[email protected]>
Cc: "Matthew Wilcox (Oracle)" <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Michel Lespinasse <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Tony Luck <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions