[PATCH v4 0/3] sparse_init rewrite

[Pavel Tatashin <pasha.tatashin@oracle.com>]

Changelog:
v4 - v3
	- Addressed comments from Dave Hansen
v3 - v1
	- Fixed two issues found by Baoquan He
v1 - v2
	- Addressed comments from Oscar Salvador

In sparse_init() we allocate two large buffers to temporary hold usemap and
memmap for the whole machine. However, we can avoid doing that if we
changed sparse_init() to operated on per-node bases instead of doing it on
the whole machine beforehand.

As shown by Baoquan
http://lkml.kernel.org/r/20180628062857.29658-1-bhe@redhat.com

The buffers are large enough to cause machine stop to boot on small memory
systems.

These patches should be applied on top of Baoquan's work, as
CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER is removed in that work.

For the ease of review, I split this work so the first patch only adds new
interfaces, the second patch enables them, and removes the old ones.

Pavel Tatashin (3):
  mm/sparse: add sparse_init_nid()
  mm/sparse: start using sparse_init_nid(), and remove old code
  mm/sparse: refactor sparse vmemmap buffer allocations

 include/linux/mm.h  |  13 +-
 mm/sparse-vmemmap.c | 111 ++++++++++-------
 mm/sparse.c         | 281 +++++++++++++++-----------------------------
 3 files changed, 170 insertions(+), 235 deletions(-)

-- 
2.18.0