On Wed 28-11-12 17:47:59, KAMEZAWA Hiroyuki wrote: > (2012/11/27 3:47), Michal Hocko wrote: [...] > > + /* > > + * Even if we found a group we have to make sure it is alive. > > + * css && !memcg means that the groups should be skipped and > > + * we should continue the tree walk. > > + * last_visited css is safe to use because it is protected by > > + * css_get and the tree walk is rcu safe. > > + */ > > + if (css == &root->css || (css && css_tryget(css))) > > + memcg = mem_cgroup_from_css(css); > > Could you note that this iterator will never visit dangling(removed) > memcg, somewhere ? OK, I can add it to the function comment but the behavior hasn't changed so I wouldn't like to confuse anybody. > Hmm, I'm not sure but it may be trouble at shrkinking dangling > kmem_cache(slab). We do not shrink slab at all. Those objects that are in a dead memcg wait for their owner tho release them which will make the dangling group eventually go away > > Costa, how do you think ? > > I guess there is no problem with swap and not against the way you go. Yes, swap should be OK. Pages charged against removed memcg will fallback to the the current's mm (try_get_mem_cgroup_from_page and __mem_cgroup_try_charge_swapin) [...] -- Michal Hocko SUSE Labs -- 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>