Messages in this thread | | | Date | Tue, 17 Feb 2009 10:12:22 +0530 | From | Balbir Singh <> | Subject | Re: [RFC][PATCH 0/4] Memory controller soft limit patches (v2) |
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* KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> [2009-02-17 13:20:39]:
> On Tue, 17 Feb 2009 13:03:52 +0900 > KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote: > > > > > 2. I don't like to change usual direct-memory-reclaim path. It will be obstacles > > > > for VM-maintaners to improve memory reclaim. memcg's LRU is designed for > > > > shrinking memory usage and not for avoiding memory shortage. IOW, it's slow routine > > > > for reclaiming memory for memory shortage. > > > > > > I don't think I agree here. Direct reclaim is the first indication of > > > shortage and if order 0 pages are short, memcg's above their soft > > > limit can be targetted first. > > > > > My "slow" means "the overhead seems to be big". The latency will increase. > > > > About 0-order > > In patch 4/4 > > + did_some_progress = mem_cgroup_soft_limit_reclaim(gfp_mask); > > + /* > > should be > > if (!order) > > did_some_progress = mem.... > above is wrong. > > if (!order && (gfp_mask & GFP_MOVABLE)) ....Hmm, but this is not correct. > I have no good idea to avoid unnecessary works. > > BTW, why don't you call soft_limit_reclaim from kswapd's path ? >
I think it has to be both kswapd and pdflush path, I can consider that option as well. That needs more thought on the design.
-- Balbir
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