memcg: update memcg_test.txt to describe memory thresholds
Decription of sanity check for memory thresholds.
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Dan Malek <dan@embeddedalley.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/cgroups/memcg_test.txt b/Documentation/cgroups/memcg_test.txt
index e011488..4d32e0e 100644
--- a/Documentation/cgroups/memcg_test.txt
+++ b/Documentation/cgroups/memcg_test.txt
@@ -396,3 +396,24 @@
memory.stat of both A and B.
See 8.2 of Documentation/cgroups/memory.txt to see what value should be
written to move_charge_at_immigrate.
+
+ 9.10 Memory thresholds
+ Memory controler implements memory thresholds using cgroups notification
+ API. You can use Documentation/cgroups/cgroup_event_listener.c to test
+ it.
+
+ (Shell-A) Create cgroup and run event listener
+ # mkdir /cgroup/A
+ # ./cgroup_event_listener /cgroup/A/memory.usage_in_bytes 5M
+
+ (Shell-B) Add task to cgroup and try to allocate and free memory
+ # echo $$ >/cgroup/A/tasks
+ # a="$(dd if=/dev/zero bs=1M count=10)"
+ # a=
+
+ You will see message from cgroup_event_listener every time you cross
+ the thresholds.
+
+ Use /cgroup/A/memory.memsw.usage_in_bytes to test memsw thresholds.
+
+ It's good idea to test root cgroup as well.