Re: OOM Killer and add_to_page_cache_locked

[Piotr Nowojski]

W dniu 07.06.2013 17:36, Michal Hocko pisze:
> On Fri 07-06-13 17:13:55, Piotr Nowojski wrote:
> > W dniu 06.06.2013 17:57, Michal Hocko pisze:
> > > > > In our system we have hit some very annoying situation (bug?) with
> > > > > cgroups. I'm writing to you, because I have found your posts on
> > > > > mailing lists with similar topic. Maybe you could help us or point
> > > > > some direction where to look for/ask.
> > > > >
> > > > > We have system with ~15GB RAM (+2GB SWAP), and we are running ~10
> > > > > heavy IO processes. Each process is using constantly 200-210MB RAM
> > > > > (RSS) and a lot of page cache. All processes are in cgroup with
> > > > > following limits:
> > > > >
> > > > > /sys/fs/cgroup/taskell2 $ cat memory.limit_in_bytes
> > > > > memory.memsw.limit_in_bytes
> > > > > 14183038976
> > > > > 15601344512
> > > I assume that memory.use_hierarchy is 1, right?
> > System has been rebooted since last test, so I can not guarantee
> > that it was set for 100%, but it should have been. Currently I'm
> > rerunning this scenario that lead to the described problem with:
> >
> > /sys/fs/cgroup/taskell2# cat memory.use_hierarchy ../memory.use_hierarchy
> > 1
> > 0
> OK, good. Your numbers suggeste that the hierachy _is_ in use. I just
> wanted to be 100% sure.

I don't know what has solved this problem, but we weren't able to 
reproduce this problem during whole weekend. Most likely there was some 
problem with our code initializing cgroups configuration regarding 
use_hierarchy (can writing 1 to memory.use_hierarchy silently fail?). I 
have added assertions for checking this parameter before starting and 
after initialization of our application. If problem reoccur, I will 
proceed as you suggested before - trying latest kernels.

Thanks, Piotr Nowojski
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