[PATCH 0/2] Implement numa node notifier

Oscar Salvador
2025-04-01T09:27:41Z

Memory notifier is a tool that allow consumers to get notified whenever
memory gets onlined or offlined in the system.
Currently, there are 10 consumers of that, but 5 out of those 10 consumers
are only interested in getting notifications when a numa node has changed its
state.
That means going from memoryless to memory-aware of vice versa.

Which means that for every {online,offline}_pages operation they get
notified even though the numa node might not have changed its state.

The first patch implements a numa node notifier that does just that, and have
those consumers register in there, so they get notified only when they are
interested.

The second patch replaces 'status_change_normal{_normal}' fields within
memory_notify with a 'nid', as that is only what we need for memory
notifer and update the only user of it (page_ext).

Consumers that are only interested in numa node states change are:

- memory-tier
- slub
- cpuset
- hmat
- cxl

Oscar Salvador (2):
mm,memory_hotplug: Implement numa node notifier
mm,memory_hotplug: Replace status_change_nid parameter in
memory_notify

drivers/acpi/numa/hmat.c | 6 +--
drivers/base/node.c | 19 +++++++++
drivers/cxl/core/region.c | 14 +++----
drivers/cxl/cxl.h | 4 +-
include/linux/memory.h | 37 ++++++++++++++++++
kernel/cgroup/cpuset.c | 2 +-
mm/memory-tiers.c | 8 ++--
mm/memory_hotplug.c | 82 +++++++++++++++++++++++++++++----------
mm/page_ext.c | 12 +-----
mm/slub.c | 22 +++++------
10 files changed, 146 insertions(+), 60 deletions(-)

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2.49.0