[PATCH v8 12/12] mm/demotion: Add sysfs ABI documentation

Aneesh Kumar K.V
2022-07-04T07:10:17Z

Add sysfs ABI documentation.

Signed-off-by: Wei Xu <weixugc@google.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
.../ABI/testing/sysfs-kernel-mm-memory-tiers | 61 +++++++++++++++++++
1 file changed, 61 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-kernel-mm-memory-tiers

diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-memory-tiers b/Documentation/ABI/testing/sysfs-kernel-mm-memory-tiers
new file mode 100644
index 000000000000..843fb59d2f3d
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-mm-memory-tiers
@@ -0,0 +1,61 @@
+What: /sys/devices/system/memtier/
+Date: June 2022
+Contact: Linux memory management mailing list <linux-mm@kvack.org>
+Description: Interface for tiered memory
+
+ This is the directory containing the information about memory tiers.
+
+ Each memory tier has its own subdirectory.
+
+ The order of memory tiers is determined by their tier ID value.
+ A higher tier ID value means a higher tier. memtier300 is higher
+ memory tier compared to memtier 100.
+
+What: /sys/devices/system/memtier/default_tier
+Date: June 2022
+Contact: Linux memory management mailing list <linux-mm@kvack.org>
+Description: Default memory tier
+
+ The default memory tier to which memory would get added via hotplug
+ if the NUMA node is not part of any memory tier
+
+What: /sys/devices/system/memtier/max_tier
+Date: June 2022
+Contact: Linux memory management mailing list <linux-mm@kvack.org>
+Description: Maximum memory tier ID supported
+
+ The max memory tier device ID we can create. Users can create memory
+ tiers in range [0 - max_tier]
+
+What: /sys/devices/system/memtier/memtierN/
+Date: June 2022
+Contact: Linux memory management mailing list <linux-mm@kvack.org>
+Description: Directory with details of a specific memory tier
+
+ This is the directory containing the information about a particular
+ memory tier, memtierN, where N is the memtier device ID (e.g. 0, 1).
+
+ The memtier device ID number itself is just an identifier and has no
+ special meaning. Its value relative to other memtiers decides the level
+ of this memtier in the tier hierarchy.
+
+
+What: /sys/devices/system/memtier/memtierN/nodelist
+Date: June 2022
+Contact: Linux memory management mailing list <linux-mm@kvack.org>
+Description: Memory tier nodelist
+
+
+ When read, list the memory nodes in the specified tier.
+
+What: /sys/devices/system/node/nodeN/memtier
+Date: June 2022
+Contact: Linux memory management mailing list <linux-mm@kvack.org>
+Description: Memory tier details for node N
+
+ When read, list the device ID of the memory tier that the node belongs
+ to. Its value is empty for a CPU-only NUMA node.
+
+ When written, the kernel moves the node into the specified memory
+ tier if the move is allowed. The tier assignments of all other
+ nodes are not affected.
--
2.36.1