Re: [PATCH 4/4] mm: shrinker: make shrinker not depend on memcg kmem

[Yang Shi]

On 6/12/19 3:11 AM, Kirill A. Shutemov wrote:
> On Tue, Jun 11, 2019 at 10:07:54PM -0700, Yang Shi wrote:
> > On 6/11/19 7:52 PM, Kirill A. Shutemov wrote:
> > > On Fri, Jun 07, 2019 at 02:07:39PM +0800, Yang Shi wrote:
> > > > Currently shrinker is just allocated and can work when memcg kmem is
> > > > enabled.  But, THP deferred split shrinker is not slab shrinker, it
> > > > doesn't make too much sense to have such shrinker depend on memcg kmem.
> > > > It should be able to reclaim THP even though memcg kmem is disabled.
> > > >
> > > > Introduce a new shrinker flag, SHRINKER_NONSLAB, for non-slab shrinker,
> > > > i.e. THP deferred split shrinker.  When memcg kmem is disabled, just
> > > > such shrinkers can be called in shrinking memcg slab.
> > > Looks like it breaks bisectability. It has to be done before makeing
> > > shrinker memcg-aware, hasn't it?
> > No, it doesn't break bisectability. But, THP shrinker just can be called
> > with kmem charge enabled without this patch.
> So, if kmem is disabled, it will not be called, right? Then it is
> regression in my opinion. This patch has to go in before 2/4.

I don't think this is a regression. "regression" should mean something 
used to work, but it is broken now. Actually, deferred split shrinker 
never works with memcg.

Anyway, either before 2/4 or after 2/4 looks ok.

>