On Wed, Apr 29, 2020 at 03:11:09PM +0300, Mike Rapoport wrote:

From: Mike Rapoport <redacted>

The CONFIG_HAVE_MEMBLOCK_NODE_MAP is used to differentiate initialization
of nodes and zones structures between the systems that have region to node
mapping in memblock and those that don't.

Currently all the NUMA architectures enable this option and for the
non-NUMA systems we can presume that all the memory belongs to node 0 and
therefore the compile time configuration option is not required.

The remaining few architectures that use DISCONTIGMEM without NUMA are
easily updated to use memblock_add_node() instead of memblock_add() and
thus have proper correspondence of memblock regions to NUMA nodes.

Still, free_area_init_node() must have a backward compatible version
because its semantics with and without CONFIG_HAVE_MEMBLOCK_NODE_MAP is
different. Once all the architectures will use the new semantics, the
entire compatibility layer can be dropped.

To avoid addition of extra run time memory to store node id for
architectures that keep memblock but have only a single node, the node id
field of the memblock_region is guarded by CONFIG_NEED_MULTIPLE_NODES and
the corresponding accessors presume that in those cases it is always 0.

Signed-off-by: Mike Rapoport <redacted>
---
 .../vm/numa-memblock/arch-support.txt         |  34 ------
 arch/alpha/mm/numa.c                          |   4 +-
 arch/arm64/Kconfig                            |   1 -

For arm64:

Acked-by: Catalin Marinas <catalin.marinas@arm.com>