Re: [PATCH] Documentation/memcg: update memcg/kmem status

Vladimir Davydov
2015-04-01T15:17:25Z

On Wed, Apr 01, 2015 at 04:44:31PM +0200, Jonathan Corbet wrote:
> On Wed, 1 Apr 2015 17:30:36 +0300
> Vladimir Davydov <vdavydov@parallels.com> wrote:
>
> > Memcg/kmem reclaim support has been finally merged. Reflect this in the
> > documentation.
>
> So the text you've removed says not to select kmem support "unless for
> development purposes." Do we now believe that this feature is ready for
> use in a production setting? If the answer is "yes," I'd be happy to
> take this through the docs tree.

I added this warning because of the following issues, which made
memcg/kmem useless:

- no reclaim support
- lack of memcg slab caches auto destruction
- several obvious races/bugs

They are all fixed now, so I think the answer is yes, it can be used in
production. There might be bugs that I am not aware of, of course, but
It must be safe to compile it in anyway, because memcg/kmem accounting
is disabled by default and must be enabled explicitly at runtime by
writing to cgroup/memory.kmem.limit_in_bytes.

Thanks,
Vladimir