[PATCH v4 0/6] Memory Hierarchy: Enable target node lookups for reserved memory

From: Dan Williams <dan.j.williams@intel.com>
To: tglx@linutronix.de, mingo@redhat.com
Cc: David Hildenbrand <david@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
	kbuild test robot <lkp@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Michal Hocko <mhocko@suse.com>, Paul Mackerras <paulus@samba.org>,
	Christoph Hellwig <hch@lst.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	x86@kernel.org, Andy Lutomirski <luto@kernel.org>,
	linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org
Subject: [PATCH v4 0/6] Memory Hierarchy: Enable target node lookups for reserved memory
Date: Tue, 21 Jan 2020 19:04:35 -0800	[thread overview]
Message-ID: <157966227494.2508551.7206194169374588977.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)

Changes since v3 [1]:
- Cleanup numa_map_to_online_node() to remove redundant "if
  (!node_online(node))" (Aneesh)

[1]: http://lore.kernel.org/r/157954696789.2239526.17707265517154476652.stgit@dwillia2-desk3.amr.corp.intel.com

---

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.

---

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

---

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                            |   31 ++++++++++++
 9 files changed, 145 insertions(+), 92 deletions(-)
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