On Mon, Mar 28, 2011 at 7:45 PM, KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote: > On Mon, 28 Mar 2011 19:46:41 -0700 > Ying Han <yinghan@xxxxxxxxxx> wrote: > >> On Mon, Mar 28, 2011 at 5:47 PM, KAMEZAWA Hiroyuki >> <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote: > >> > >> >> By saying that, memcg simplified the memory accounting per-cgroup but >> >> the memory isolation is broken. This is one of examples where pages >> >> are shared between global LRU and per-memcg LRU. It is easy to get >> >> cgroup-A's page evicted by adding memory pressure to cgroup-B. >> >> >> > If you overcommit....Right ? >> >> yes, we want to support the configuration of over-committing the >> machine w/ limit_in_bytes. >> > > Then, soft_limit is a feature for fixing the problem. If you have problem > with soft_limit, let's fix it. The current implementation of soft_limit works as best-effort and some improvement are needed. Without distracting much from this thread, simply saying it is not optimized on which cgroup to pick from the per-zone RB-tree. > > >> > >> > >> >> The approach we are thinking to make the page->lru exclusive solve the >> >> problem. and also we should be able to break the zone->lru_lock >> >> sharing. >> >> >> > Is zone->lru_lock is a problem even with the help of pagevecs ? >> >> > If LRU management guys acks you to isolate LRUs and to make kswapd etc.. >> > more complex, okay, we'll go that way. >> >> I would assume the change only apply to memcg users , otherwise >> everything is leaving in the global LRU list. >> >> This will _change_ the whole memcg design and concepts Maybe memcg >> should have some kind of balloon driver to >> > work happy with isolated lru. >> >> We have soft_limit hierarchical reclaim for system memory pressure, >> and also we will add per-memcg background reclaim. Both of them do >> targeting reclaim on per-memcg LRUs, and where is the balloon driver >> needed? >> > > If soft_limit is _not_ enough. And I think you background reclaim should > be work with soft_limit and be triggered by global memory pressure. This is something i can think about. Also i think we agree that we should have efficient target reclaim so the global LRU scanning should be eliminated. > > As wrote in other mail, it's not called via direct reclaim. > Maybe its the 1st point to be shooted rather than trying big change. Agree on this. --Ying > > > > > Thanks, > -Kame > > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx 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>