Merge tag 'v5.4-rc4' into docs-next
I need to pick up the independent changes made to
Documentation/core-api/memory-allocation.rst to be able to merge further
work without creating a total mess.
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 26d1cde..ed912315 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -615,8 +615,8 @@
Protections
-----------
-A cgroup is protected to be allocated upto the configured amount of
-the resource if the usages of all its ancestors are under their
+A cgroup is protected upto the configured amount of the resource
+as long as the usages of all its ancestors are under their
protected levels. Protections can be hard guarantees or best effort
soft boundaries. Protections can also be over-committed in which case
only upto the amount available to the parent is protected among
@@ -1096,7 +1096,10 @@
is within its effective min boundary, the cgroup's memory
won't be reclaimed under any conditions. If there is no
unprotected reclaimable memory available, OOM killer
- is invoked.
+ is invoked. Above the effective min boundary (or
+ effective low boundary if it is higher), pages are reclaimed
+ proportionally to the overage, reducing reclaim pressure for
+ smaller overages.
Effective min boundary is limited by memory.min values of
all ancestor cgroups. If there is memory.min overcommitment
@@ -1119,6 +1122,10 @@
cgroup is within its effective low boundary, the cgroup's
memory won't be reclaimed unless there is no reclaimable
memory available in unprotected cgroups.
+ Above the effective low boundary (or
+ effective min boundary if it is higher), pages are reclaimed
+ proportionally to the overage, reducing reclaim pressure for
+ smaller overages.
Effective low boundary is limited by memory.low values of
all ancestor cgroups. If there is memory.low overcommitment
@@ -2482,8 +2489,10 @@
becomes self-defeating.
The memory.low boundary on the other hand is a top-down allocated
-reserve. A cgroup enjoys reclaim protection when it's within its low,
-which makes delegation of subtrees possible.
+reserve. A cgroup enjoys reclaim protection when it's within its
+effective low, which makes delegation of subtrees possible. It also
+enjoys having reclaim pressure proportional to its overage when
+above its effective low.
The original high boundary, the hard limit, is defined as a strict
limit that can not budge, even if the OOM killer has to be called.