summaryrefslogtreecommitdiffstats
path: root/Documentation/admin-guide/cgroup-v2.rst
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/admin-guide/cgroup-v2.rst')
-rw-r--r--Documentation/admin-guide/cgroup-v2.rst72
1 files changed, 57 insertions, 15 deletions
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 74cdeaed9f7a..8a2c52d5c53b 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -1001,14 +1001,44 @@ PAGE_SIZE multiple when read back.
The total amount of memory currently being used by the cgroup
and its descendants.
+ memory.min
+ A read-write single value file which exists on non-root
+ cgroups. The default is "0".
+
+ Hard memory protection. If the memory usage of a cgroup
+ 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.
+
+ Effective min boundary is limited by memory.min values of
+ all ancestor cgroups. If there is memory.min overcommitment
+ (child cgroup or cgroups are requiring more protected memory
+ than parent will allow), then each child cgroup will get
+ the part of parent's protection proportional to its
+ actual memory usage below memory.min.
+
+ Putting more memory than generally available under this
+ protection is discouraged and may lead to constant OOMs.
+
+ If a memory cgroup is not populated with processes,
+ its memory.min is ignored.
+
memory.low
A read-write single value file which exists on non-root
cgroups. The default is "0".
- Best-effort memory protection. If the memory usages of a
- cgroup and all its ancestors are below their low boundaries,
- the cgroup's memory won't be reclaimed unless memory can be
- reclaimed from unprotected cgroups.
+ Best-effort memory protection. If the memory usage of a
+ cgroup is within its effective low boundary, the cgroup's
+ memory won't be reclaimed unless memory can be reclaimed
+ from unprotected cgroups.
+
+ Effective low boundary is limited by memory.low values of
+ all ancestor cgroups. If there is memory.low overcommitment
+ (child cgroup or cgroups are requiring more protected memory
+ than parent will allow), then each child cgroup will get
+ the part of parent's protection proportional to its
+ actual memory usage below memory.low.
Putting more memory than generally available under this
protection is discouraged.
@@ -1199,6 +1229,27 @@ PAGE_SIZE multiple when read back.
Swap usage hard limit. If a cgroup's swap usage reaches this
limit, anonymous memory of the cgroup will not be swapped out.
+ memory.swap.events
+ A read-only flat-keyed file which exists on non-root cgroups.
+ The following entries are defined. Unless specified
+ otherwise, a value change in this file generates a file
+ modified event.
+
+ max
+ The number of times the cgroup's swap usage was about
+ to go over the max boundary and swap allocation
+ failed.
+
+ fail
+ The number of times swap allocation failed either
+ because of running out of swap system-wide or max
+ limit.
+
+ When reduced under the current usage, the existing swap
+ entries are reclaimed gradually and the swap usage may stay
+ higher than the limit for an extended period of time. This
+ reduces the impact on the workload and memory management.
+
Usage Guidelines
~~~~~~~~~~~~~~~~
@@ -1934,17 +1985,8 @@ system performance due to overreclaim, to the point where the feature
becomes self-defeating.
The memory.low boundary on the other hand is a top-down allocated
-reserve. A cgroup enjoys reclaim protection when it and all its
-ancestors are below their low boundaries, which makes delegation of
-subtrees possible. Secondly, new cgroups have no reserve per default
-and in the common case most cgroups are eligible for the preferred
-reclaim pass. This allows the new low boundary to be efficiently
-implemented with just a minor addition to the generic reclaim code,
-without the need for out-of-band data structures and reclaim passes.
-Because the generic reclaim code considers all cgroups except for the
-ones running low in the preferred first reclaim pass, overreclaim of
-individual groups is eliminated as well, resulting in much better
-overall workload performance.
+reserve. A cgroup enjoys reclaim protection when it's within its low,
+which makes delegation of subtrees possible.
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.