Thread (35 messages) 35 messages, 6 authors, 2011-04-01

Re: [RFC 0/3] Implementation of cgroup isolation

From: Ying Han <hidden>
Date: 2011-03-29 03:02:48
Also in: lkml

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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