(I'll be off from my office soon, and I won't be responsive in the following 3 days.) I'm working on converting memcg to use cgroup->id, and then we can kill css_id. Now memcg has its own refcnt, so when a cgroup is destroyed, the memcg can still be alive. This patchset converts memcg to always use css_get/put, so memcg will have the same life cycle as its corresponding cgroup, and then it's always safe for memcg to use cgroup->id. The historical reason that memcg didn't use css_get in some cases, is that cgroup couldn't be removed if there're still css refs. The situation has changed so that rmdir a cgroup will succeed regardless css refs, but won't be freed until css refs goes down to 0. This is an early post, and it's NOT TESTED. I just want to see if the changes are fine in general. btw, after this patchset I think we don't need to free memcg via RCU, because cgroup is already freed in RCU callback. Note this patchset is based on a few memcg fixes I sent (but hasn't been accepted) -- kernel/cgroup.c | 10 ++++++++ mm/memcontrol.c | 129 ++++++++++++++++++++++++++++++++++++++------------------------------------------------------- 2 files changed, 62 insertions(+), 77 deletions(-) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>