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-rw-r--r--Documentation/cgroups/memory.txt11
1 files changed, 4 insertions, 7 deletions
diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index 2622115276a..1829c65f837 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -535,17 +535,15 @@ Note:
5.3 swappiness
-Similar to /proc/sys/vm/swappiness, but affecting a hierarchy of groups only.
+Similar to /proc/sys/vm/swappiness, but only affecting reclaim that is
+triggered by this cgroup's hard limit. The tunable in the root cgroup
+corresponds to the global swappiness setting.
+
Please note that unlike the global swappiness, memcg knob set to 0
really prevents from any swapping even if there is a swap storage
available. This might lead to memcg OOM killer if there are no file
pages to reclaim.
-Following cgroups' swappiness can't be changed.
-- root cgroup (uses /proc/sys/vm/swappiness).
-- a cgroup which uses hierarchy and it has other cgroup(s) below it.
-- a cgroup which uses hierarchy and not the root of hierarchy.
-
5.4 failcnt
A memory cgroup provides memory.failcnt and memory.memsw.failcnt files.
@@ -754,7 +752,6 @@ You can disable the OOM-killer by writing "1" to memory.oom_control file, as:
#echo 1 > memory.oom_control
-This operation is only allowed to the top cgroup of a sub-hierarchy.
If OOM-killer is disabled, tasks under cgroup will hang/sleep
in memory cgroup's OOM-waitqueue when they request accountable memory.