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[v3,0/4] Add interfaces for ACPI MRRM table

Message ID 20250410223207.257722-1-tony.luck@intel.com
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Series Add interfaces for ACPI MRRM table | expand

Message

Tony Luck April 10, 2025, 10:32 p.m. UTC 
Memory used to be homogeneous. Then NUMA came along. Later different
types of memory (persistent memory, on-package high bandwidth memory,
CXL attached memory).

Each type of memory has its own performance characteristics, and users
will need to monitor and control access by type.

The MRRM solution is to tag physical address ranges with "region IDs"
so that platform firmware[1] can indicate the type of memory for each
range (with separate tags available for local vs. remote access to
each range). Note that these ranges can include addresses reserved
for future hotplugged memory.

The region IDs will be used to provide separate event counts for each
region for "perf" and for the "resctrl" file system to monitor and
control memory bandwidth in each region.

Users will need to know the address range(s) that are part of each
region. This patch series adds
	/sys/firmware/acpi/memory_ranges/rangeX
directories to provide user space accessible enumeration.

-Tony

[1] MRRM definition allow for future expansion for the OS to assign
these region IDs.

Changes since version 2 here:
https://lore.kernel.org/all/20250227224828.306537-1-tony.luck@intel.com/

1) Changes in patch 1 are now in the R2025_04_04 release of the ACPICA
project (plus PR #1015 to fix a naming issue for "acpisrc" conversion
to Linux format).

2) Split the /sys/firmware part into its own patch. Linux resctrl only
needs the enumeration of the number of supported regions.

3) Added a "node" file to each of the rangeX directories to report
which NUMA node the range belongs to.

4) Dropped the debug-only last patch in the series as I now have
other methods to test this code.

Tony Luck (4):
  ACPICA: Define MRRM ACPI table
  ACPI/MRRM: Minimal parse of ACPI MRRM table
  ACPI/MRRM: Add /sys files to describe memory ranges
  ACPI: Add documentation for exposing MRRM data

 include/linux/acpi.h                          |   6 +
 include/acpi/actbl1.h                         |   7 +
 include/acpi/actbl2.h                         |  42 ++++
 drivers/acpi/acpi_mrrm.c                      | 185 ++++++++++++++++++
 Documentation/ABI/testing/sysfs-firmware-acpi |  21 ++
 arch/x86/Kconfig                              |   1 +
 drivers/acpi/Kconfig                          |   3 +
 drivers/acpi/Makefile                         |   1 +
 8 files changed, 266 insertions(+)
 create mode 100644 drivers/acpi/acpi_mrrm.c


base-commit: 0af2f6be1b4281385b618cb86ad946eded089ac8