tree ebf6784f883a2b791d51366ecb18b0dbdf3f3029
parent 0e8fb9312fbaf1a687dd731b04d8ab3121c4ff5a
author Dan Williams <dan.j.williams@intel.com> 1458249598 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1458252574 -0700

mm: ZONE_DEVICE depends on SPARSEMEM_VMEMMAP

The primary use case for devm_memremap_pages() is to allocate an memmap
array from persistent memory.  That capabilty requires vmem_altmap which
requires SPARSEMEM_VMEMMAP.

Also, without SPARSEMEM_VMEMMAP the addition of ZONE_DEVICE expands
ZONES_WIDTH and triggers the:

"Unfortunate NUMA and NUMA Balancing config, growing page-frame for
last_cpupid."

...warning in mm/memory.c.  SPARSEMEM_VMEMMAP=n && ZONE_DEVICE=y is not
a configuration we should worry about supporting.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>