memcg: update document to mention that swapoff should be tested

Considering the recently found problem "memcg: fix refcnt handling at
swapoff", it's better to mention swapoff behavior in the memcg_test
document.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Li Zefan <lizf@cn.fujitsu.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>
This commit is contained in:
KAMEZAWA Hiroyuki 2009-01-29 14:25:14 -08:00 коммит произвёл Linus Torvalds
Родитель 85d9fc89fb
Коммит 8d50d369d1
1 изменённых файлов: 22 добавлений и 2 удалений

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@ -1,6 +1,6 @@
Memory Resource Controller(Memcg) Implementation Memo.
Last Updated: 2008/12/15
Base Kernel Version: based on 2.6.28-rc8-mm.
Last Updated: 2009/1/19
Base Kernel Version: based on 2.6.29-rc2.
Because VM is getting complex (one of reasons is memcg...), memcg's behavior
is complex. This is a document for memcg's internal behavior.
@ -340,3 +340,23 @@ Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y.
# mount -t cgroup none /cgroup -t cpuset,memory,cpu,devices
and do task move, mkdir, rmdir etc...under this.
9.7 swapoff.
Besides management of swap is one of complicated parts of memcg,
call path of swap-in at swapoff is not same as usual swap-in path..
It's worth to be tested explicitly.
For example, test like following is good.
(Shell-A)
# mount -t cgroup none /cgroup -t memory
# mkdir /cgroup/test
# echo 40M > /cgroup/test/memory.limit_in_bytes
# echo 0 > /cgroup/test/tasks
Run malloc(100M) program under this. You'll see 60M of swaps.
(Shell-B)
# move all tasks in /cgroup/test to /cgroup
# /sbin/swapoff -a
# rmdir /test/cgroup
# kill malloc task.
Of course, tmpfs v.s. swapoff test should be tested, too.