[Devel] [RFC] how should we deal with dead memcgs' kmem caches?

[Christoph Lameter]

On Sun, 20 Apr 2014, Vladimir Davydov wrote:

> * Way #1 - prevent dead kmem caches from caching slabs on free *
>
> We can modify sl[au]b implementation so that it won't cache any objects
> on free if the kmem cache belongs to a dead memcg. Then it'd be enough
> to drain per-cpu pools of all dead kmem caches on css offline - no new
> slabs will be added there on further frees, and the last object will go
> away along with the last slab.

You can call kmem_cache_shrink() to force slab allocators to drop cached
objects after a free.