Re: [RFC 0/3] Implementation of cgroup isolation
From: Ying Han <hidden>
Date: 2011-03-29 03:02:48
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On Mon, Mar 28, 2011 at 7:29 PM, KAMEZAWA Hiroyuki [off-list ref] wrote:
On Tue, 29 Mar 2011 09:47:56 +0900 KAMEZAWA Hiroyuki [off-list ref] wrote:quoted
On Mon, 28 Mar 2011 17:37:02 -0700 Ying Han [off-list ref] wrote:quoted
quoted
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. This will _change_ the whole memcg design and concepts Maybe memcg should have some kind of balloon driver to work happy with isolated lru. But my current standing position is "never bad effects global reclaim". So, I'm not very happy with the solution. If we go that way, I guess we'll think we should have pseudo nodes/zones, which was proposed in early days of resource controls.(not cgroup).BTW, against isolation, I have one thought. Now, soft_limit_reclaim is not called in direct-reclaim path just because we thought kswapd works enough well. If necessary, I think we can put soft-reclaim call in generic do_try_to_free_pages(order=0).
We were talking about that internally and that definitely make sense to add.
So, isolation problem can be reduced to some extent, isn't it ? Algorithm of softlimit _should_ be updated. I guess it's not heavily tested feature.
Agree and that is something we might want to go and fix. soft_limit in general provides a nice way to over_committing the machine, and still have control of doing target reclaim under system memory pressure.
About ROOT cgroup, I think some daemon application should put _all_ process to some controled cgroup. So, I don't want to think about limiting on ROOT cgroup without any justification. I'd like you to devide 'the talk on performance' and 'the talk on feature'. "This makes makes performance better! ...and add an feature" sounds bad to me.
Ok, then let's stick on the memory isolation feature now :) --Ying
Thanks, -Kame
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