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authorTejun Heo <tj@kernel.org>2015-09-18 17:54:22 -0400
committerTejun Heo <tj@kernel.org>2015-09-18 17:54:22 -0400
commit4a07c222d3afb00e1113834fee38d23a8e5d71dc (patch)
tree10000327cd4426ba55b75b5c9d8954a8bd0bf2a5 /Documentation/cgroups/unified-hierarchy.txt
parent9e10a130d9b62af976d17d120c95f3650769312c (diff)
cgroup: replace "cgroup.populated" with "cgroup.events"
memcg already uses "memory.events" for event reporting and other controllers may need event reporting too. Let's standardize on "$SUBSYS.events" interface file for reporting events which don't happen too frequently and thus can share event notification. "cgroup.populated" is replaced with "populated" field in "cgroup.events" and documentation is updated accordingly. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org>
Diffstat (limited to 'Documentation/cgroups/unified-hierarchy.txt')
-rw-r--r--Documentation/cgroups/unified-hierarchy.txt15
1 files changed, 10 insertions, 5 deletions
diff --git a/Documentation/cgroups/unified-hierarchy.txt b/Documentation/cgroups/unified-hierarchy.txt
index e0975c2cf03d..176b940f8327 100644
--- a/Documentation/cgroups/unified-hierarchy.txt
+++ b/Documentation/cgroups/unified-hierarchy.txt
@@ -341,11 +341,11 @@ is riddled with issues.
unnecessarily complicated and probably done this way because event
delivery itself was expensive.
-Unified hierarchy implements an interface file "cgroup.populated"
-which can be used to monitor whether the cgroup's subhierarchy has
-tasks in it or not. Its value is 0 if there is no task in the cgroup
-and its descendants; otherwise, 1. poll and [id]notify events are
-triggered when the value changes.
+Unified hierarchy implements "populated" field in "cgroup.events"
+interface file which can be used to monitor whether the cgroup's
+subhierarchy has tasks in it or not. Its value is 0 if there is no
+task in the cgroup and its descendants; otherwise, 1. poll and
+[id]notify events are triggered when the value changes.
This is significantly lighter and simpler and trivially allows
delegating management of subhierarchy - subhierarchy monitoring can
@@ -435,6 +435,11 @@ may be specified in any order and not all pairs have to be specified.
the first entry in the file. Specific entries can use "default" as
its value to indicate inheritance of the default value.
+- For events which are not very high frequency, an interface file
+ "events" should be created which lists event key value pairs.
+ Whenever a notifiable event happens, file modified event should be
+ generated on the file.
+
5-4. Per-Controller Changes