Re: [RFC][PATCH] memcg soft limit (yet another new design) v1

[KAMEZAWA Hiroyuki]

On Sat, 28 Mar 2009 23:41:00 +0530
Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote:

> * KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> [2009-03-27 13:59:33]:
> 
> > ==brief test result==
> > On 2CPU/1.6GB bytes machine. create group A and B
> >   A.  soft limit=300M
> >   B.  no soft limit
> > 
> >   Run a malloc() program on B and allcoate 1G of memory. The program just
> >   sleeps after allocating memory and no memory refernce after it.
> >   Run make -j 6 and compile the kernel.
> > 
> >   When vm.swappiness = 60  => 60MB of memory are swapped out from B.
> >   When vm.swappiness = 10  => 1MB of memory are swapped out from B    
> > 
> >   If no soft limit, 350MB of swap out will happen from B.(swapiness=60)
> >
> 
> I ran the same tests, booted the machine with mem=1700M and maxcpus=2
> 
with your patch ?

> Here is what I see with
> 
> A has a swapout of 344M and B has not swapout at all, since B is
> always under its soft limit. vm.swappiness is set to 60
> 
> I think the above is more along the lines of the expected functional behaviour. 
> 

yes. but it's depend on workload (and fortune?) of A in this implementation.
Follwing is what I think now. We need some changes to vmscanc, later.

explain)
    This patch rotate memcg's page to the top of LRU. But, LRU is divided into
    INACTIVE/ACTIVE. So, sometimes, memcg's INACTIVE LRU can be empty and
    pages from other group can be reclaimed.
    In my test, group A's RSS usage can be 1-2M sometimes.

Thanks,
-Kame
    






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