Re: [PATCH RFC] memcg: revert kmem.tcp accounting

Michal Hocko
2014-09-12T17:18:09Z

On Fri 12-09-14 19:26:58, Vladimir Davydov wrote:
> memory.kmem.tcp.limit_in_bytes works as the system-wide tcp_mem sysctl,
> but per memory cgroup. While the existence of the latter is justified
> (it prevents the system from becoming unusable due to uncontrolled tcp
> buffers growth) the reason why we need such a knob in containers isn't
> clear to me.

Parallels was the primary driver for this change. I haven't heard of
anybody using the feature other than Parallels. I also remember there
was a strong push for this feature before it was merged besides there
were some complains at the time. I do not remember details (and I am
one half way gone for the weekend now) so I do not have pointers to
discussions.

I would love to get rid of the code and I am pretty sure that networking
people would love this go even more. I didn't plan to provide kmem.tcp.*
knobs for the cgroups v2 interface but getting rid of it altogether
sounds even better. I am just not sure whether some additional users
grown over time.
Nevertheless I am really curious. What has changed that Parallels is not
interested in kmem.tcp anymore?

[...]

Anyway, more than welcome
Acked-by: Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>

In case we happened to grow more users, which I hope hasn't happened, we
would need to keep this around at least with the legacy cgroups API.
--
Michal Hocko
SUSE Labs