Hello hannes ,Michal,and Tejun:
i using memcg v1, but some reason i want to context to memcg v2,
but i can't, here is my step:
#cat /proc/cgroups
#subsys_name hierarchy num_cgroups enabled
memory 5 1 1
#cd /sys/fs/cgroup/memory
#mkdir a
#echo 0 > a/cgroup.procs
#sleep 1
#echo 0 > cgroup.procs
#cat /proc/cgroups
#subsys_name hierarchy num_cgroups enabled
memory 5 2 1
the num_cgroups not go to "1"
so it will lead to can't context to memcg 2
#cd ..
#umount memory
umount: /sys/fs/cgroup/memory: target is busy.
(In some cases useful info about processes that use
the device is found by lsof(8) or fuser(1))
and i have tracked the root cause, i found that "b2052564e66d mm: memcontrol: continue cache reclaim from offlined groups"
from Johannes Weiner, remove mem_cgroup_reparent_charges when mem_cgroup_css_offline, so the css->refcount
not go to "0", so the css_release not call when rmdir cgroup, and nr_cgroups not released.
so i want to ask does it reasonable can't context between v1 and v2��.n��������+%������w��{.n������.����n�r������&��z�ޗ�zf���h���~����������_��+v���)ߣ�
