Re: memcg cgroup controller & sbrk interaction

Re: memcg cgroup controller & sbrk interaction

[Michal Hocko]

On Thu 07-06-12 18:19:07, Ron Chen wrote:
[...]
> However, not only us, but others have found that the memcg controller
> does not cause sbrk(2) or mmap(2) to return error when the cgroup is
> under high memory pressure.

Yes, because memory controller tracks the allocated memory (with page
granularity) rather than address space. So the memory is accounted when
it is faulted in.

> Further, when the amount of free memory is really low, the Linux
> Kernel OOM killer picks something and kills it.

Yes, this is the result of the design when the memory is tracked during
page faults.

> http://www.spinics.net/lists/cgroups/msg02622.html
> 
> 
> We also would like to see if it is technically possible for the
> Virtual Memory Manager to interact with the memory controller
> properly and give us the semantics of setrlimit(2).

What prevents you from using setrlimit from inside the group?

-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic

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