Re: [PATCH 2/2] mm, slab: Extend vm/drop_caches to shrink kmem slabs

[Christopher Lameter]

On Thu, 27 Jun 2019, Roman Gushchin wrote:

> so that objects belonging to different memory cgroups can share the same page
> and kmem_caches.
>
> It's a fairly big change though.

Could this be done at another level? Put a cgoup pointer into the
corresponding structures and then go back to just a single kmen_cache for
the system as a whole? You can still account them per cgroup and there
will be no cleanup problem anymore. You could scan through a slab cache
to remove the objects of a certain cgroup and then the fragmentation
problem that cgroups create here will be handled by the slab allocators in
the traditional way. The duplication of the kmem_cache was not designed
into the allocators but bolted on later.