Messages in this thread | | | Date | Tue, 31 Mar 2009 12:19:02 +0530 | From | Balbir Singh <> | Subject | Re: [RFC][PATCH] memcg soft limit (yet another new design) v1 |
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* KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> [2009-03-31 15:28:43]:
> On Tue, 31 Mar 2009 11:40:10 +0530 > Balbir Singh <balbir@linux.vnet.ibm.com> wrote: > > > > > Swapout for A? For A it is expected, but for B it is not. How many > > > > nodes do you have on your machine? Any fake numa nodes? > > > > > > > Of course, from B. > > > > > > > I asked because I see A have a swapout of 350 MB, which is expected > > since it is way over its soft limit. > > > gcc doesn't use so much RSS..ld ?
Yes, the ld step consumes a lot of memory, depending on file size and number of parallel tasks, memory consumption does go up.
> > > > Nothing special boot options. My test was on VMware 2cpus/1.6GB memory. > > > > > > I wonder why swapout can be 0 on your test. Do you add some extra hooks to > > > kswapd ? > > > > > > > Nope.. no special hooks to kswapd. B never enters the RB-Tree and thus > > never hits the memcg soft limit reclaim path. kswapd can reclaim from > > it, but it grows back quickly. > Why grows back ? tasks in B sleeps ?
Since B continuously consumes memory
> > > At some point, memcg soft limit reclaim > > hits A and reclaims memory from it, allowing B to run without any > > problems. I am talking about the state at the end of the experiment. > > > Considering LRU rotation (ACTIVE->INACTIVE), pages in group B never goes back > to ACTIVE list and can be the first candidates for swap-out via kswapd. > > Hmm....kswapd doesn't work at all ? > > (or 1700MB was too much.) >
No 1700MB is not too much, since we reclaim from A towards the end when ld runs. I need to investigate more and look at the watermarks, may be soft limit reclaim reclaims enough and/or the watermarks are not very high. I use fake NUMA nodes as well.
> Thanks, > -Kame > >
-- Balbir
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