Re: [RFC PATCH 0/8] memcg: Enable fine-grained per process memory control

[Chris Down]

peterz@xxxxxxxxxxxxx writes:
> On Mon, Aug 17, 2020 at 10:08:23AM -0400, Waiman Long wrote:
> > Memory controller can be used to control and limit the amount of
> > physical memory used by a task. When a limit is set in "memory.high" in
> > a v2 non-root memory cgroup, the memory controller will try to reclaim
> > memory if the limit has been exceeded. Normally, that will be enough
> > to keep the physical memory consumption of tasks in the memory cgroup
> > to be around or below the "memory.high" limit.
> >
> > Sometimes, memory reclaim may not be able to recover memory in a rate
> > that can catch up to the physical memory allocation rate. In this case,
> > the physical memory consumption will keep on increasing.
>
> Then slow down the allocator? That's what we do for dirty pages too, we
> slow down the dirtier when we run against the limits.

We already do that since v5.4. I'm wondering whether Waiman's customer is just 
running with a too-old kernel without 0e4b01df865 ("mm, memcg: throttle 
allocators when failing reclaim over memory.high") backported.