[PATCH 4/4] memcg: Document memory.low_limit_in_bytes

Michal Hocko
2014-04-28T12:28:04Z

Describe low_limit_in_bytes and its effect.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
---
Documentation/cgroups/memory.txt | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index add1be001416..a52913fe96fb 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -57,6 +57,7 @@ Brief summary of control files.
memory.memsw.usage_in_bytes # show current res_counter usage for memory+Swap
(See 5.5 for details)
memory.limit_in_bytes # set/show limit of memory usage
+ memory.low_limit_in_bytes # set/show low limit for memory reclaim
memory.memsw.limit_in_bytes # set/show limit of memory+Swap usage
memory.failcnt # show the number of memory usage hits limits
memory.memsw.failcnt # show the number of memory+Swap hits limits
@@ -249,6 +250,14 @@ is the objective of the reclaim. The global reclaim aims at balancing
zones' watermarks while the limit reclaim frees some memory to allow new
charges.

+Groups might be also protected from both global and limit reclaim by
+low_limit_in_bytes knob. If the limit is non-zero the reclaim logic
+doesn't include groups (and their subgroups - see 6. Hierarchy support)
+which are bellow the low limit if there is other eligible cgroup in the
+reclaimed hierarchy. If all groups which participate reclaim are under
+their low limits then all of them are reclaimed and the low limit is
+ignored.
+
NOTE: Hard limit reclaim does not work for the root cgroup, since we cannot set
any limits on the root cgroup.

--
2.0.0.rc0