[v3,0/6] Memory Hierarchy: Enable target node lookups for reserved memory

Message

Dan Williams Jan. 20, 2020, 7:02 p.m. UTC

Changes since v2 [1]:
- Fix numa_cleanup_meminfo() to skip trimming reserved ranges to max_pfn.

- Collect Michael's acked-by

[1]: http://lore.kernel.org/r/[e-mail]

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Merge notes:

x86 folks: This has an ack from Rafael for ACPI, and Michael for Power.
With an x86 ack I plan to take this through the libnvdimm tree provided
the x86 touches look ok to you.

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Cover:

Arrange for platform numa info to be preserved for determining
'target_node' data. Where a 'target_node' is the node a reserved memory
range will become when it is onlined.

This new infrastructure is expected to be more valuable over time for
Memory Tiers / Hierarchy management as more platforms (via the ACPI HMAT
and EFI Specific Purpose Memory) publish reserved or "soft-reserved"
ranges to Linux. Linux system administrators will expect to be able to
interact with those ranges with a unique numa node number when/if that
memory is onlined via the dax_kmem driver [2].

One configuration that currently fails to properly convey the target
node for the resulting memory hotplug operation is persistent memory
defined by the memmap=nn!ss parameter. For example, today if node1 is a
memory only node, and all the memory from node1 is specified to
memmap=nn!ss and subsequently onlined, it will end up being onlined as
node0 memory. As it stands, memory_add_physaddr_to_nid() can only
identify online nodes and since node1 in this example has no online cpus
/ memory the target node is initialized node0.

The fix is to preserve rather than discard the numa_meminfo entries that
are relevant for reserved memory ranges, and to uplevel the node
distance helper for determining the "local" (closest) node relative to
an initiator node.

[2]: https://pmem.io/ndctl/daxctl-reconfigure-device.html

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Dan Williams (6):
      ACPI: NUMA: Up-level "map to online node" functionality
      mm/numa: Skip NUMA_NO_NODE and online nodes in numa_map_to_online_node()
      powerpc/papr_scm: Switch to numa_map_to_online_node()
      x86/mm: Introduce CONFIG_KEEP_NUMA
      x86/numa: Provide a range-to-target_node lookup facility
      libnvdimm/e820: Retrieve and populate correct 'target_node' info


 arch/powerpc/platforms/pseries/papr_scm.c |   21 --------
 arch/x86/Kconfig                          |    1 
 arch/x86/mm/numa.c                        |   74 +++++++++++++++++++++++------
 drivers/acpi/numa/srat.c                  |   41 ----------------
 drivers/nvdimm/e820.c                     |   18 ++-----
 include/linux/acpi.h                      |   23 +++++++++
 include/linux/numa.h                      |   23 +++++++++
 mm/Kconfig                                |    5 ++
 mm/mempolicy.c                            |   35 ++++++++++++++
 9 files changed, 149 insertions(+), 92 deletions(-)