On Fri, Apr 27, 2012 at 03:02:22PM +0900, KAMEZAWA Hiroyuki wrote: > attach_task() is done under cgroup_mutex() but ->pre_destroy() callback > in rmdir() isn't called under cgroup_mutex(). > > It's better to avoid attaching a task to a cgroup which > is under pre_destroy(). Considering memcg, the attached task may > increase resource usage after memcg's pre_destroy() confirms that > memcg is empty. This is not good. > > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Hmm... once memcg's pre_destroy() can't fail, I think what we should do is marking a cgroup DEAD before calling pre_destroy() and the existing cgroup_is_removed() check should be enough. Patches upto this point already make ->pre_destroy() not fail, right? Thanks. -- tejun -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>