[PATCH 00/16] Memory Hierarchy: Enable target node lookups for reserved memory

Dan Williams
2019-11-07T04:10:55Z

Yes, this patch series looks like a pile of boring libnvdimm cleanups,
but buried at the end are some small gems that testing with libnvdimm
uncovered. These gems will prove more valuable over time for Memory
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 [1].

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.

The first 12 patches are cleanups to make sure that all nvdimm devices
and their children properly export a numa_node attribute. The switch to
a device-type is less code and less error prone as a result.

Patch 13 and 14 are the core changes (gems) to allow numa node
information for offline memory to be tracked.

Patches 15 and 16 use this new capability to fix the conveyance of numa
node information for memmap=nn!ss assignments. See patch 16 for more
details.

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

---

Dan Williams (16):
libnvdimm: Move attribute groups to device type
libnvdimm: Move region attribute group definition
libnvdimm: Move nd_device_attribute_group to device_type
libnvdimm: Move nd_numa_attribute_group to device_type
libnvdimm: Move nd_region_attribute_group to device_type
libnvdimm: Move nd_mapping_attribute_group to device_type
libnvdimm: Move nvdimm_attribute_group to device_type
libnvdimm: Move nvdimm_bus_attribute_group to device_type
dax: Create a dax device_type
dax: Simplify root read-only definition for the 'resource' attribute
libnvdimm: Simplify root read-only definition for the 'resource' attribute
dax: Add numa_node to the default device-dax attributes
acpi/mm: Up-level "map to online node" functionality
x86/numa: Provide a range-to-target_node lookup facility
libnvdimm/e820: Drop the wrapper around memory_add_physaddr_to_nid
libnvdimm/e820: Retrieve and populate correct 'target_node' info

arch/powerpc/platforms/pseries/papr_scm.c | 25 ---
arch/x86/mm/numa.c | 72 ++++++++-
drivers/acpi/nfit/core.c | 7 -
drivers/acpi/numa.c | 41 -----
drivers/dax/bus.c | 22 ++-
drivers/nvdimm/btt_devs.c | 24 +--
drivers/nvdimm/bus.c | 15 +-
drivers/nvdimm/core.c | 8 +
drivers/nvdimm/dax_devs.c | 27 +--
drivers/nvdimm/dimm_devs.c | 30 ++--
drivers/nvdimm/e820.c | 30 ----
drivers/nvdimm/namespace_devs.c | 77 +++++-----
drivers/nvdimm/nd.h | 5 -
drivers/nvdimm/of_pmem.c | 13 --
drivers/nvdimm/pfn_devs.c | 38 ++---
drivers/nvdimm/region_devs.c | 235 +++++++++++++++--------------
include/linux/acpi.h | 23 +++
include/linux/libnvdimm.h | 7 -
include/linux/memory_hotplug.h | 6 +
include/linux/numa.h | 2
mm/mempolicy.c | 30 ++++
21 files changed, 382 insertions(+), 355 deletions(-)