Re: [PATCH v2 1/2] mm: Uncharge poisoned pages

Balbir Singh
2017-04-26T03:45:17Z

> > > static int delete_from_lru_cache(struct page *p)
> > > {
> > > + if (memcg_kmem_enabled())
> > > + memcg_kmem_uncharge(p, 0);
> > > +
> >
> > The changelog is not quite clear, so we are uncharging a page using
> > memcg_kmem_uncharge for a page in swap cache/page cache?
>
> Hi Balbir,
>
> Yes, in the normal page lifecycle, uncharge is done in page free time.
> But in memory error handling case, in-use pages (i.e. swap cache and page
> cache) are removed from normal path and they don't pass page freeing code.
> So I think that this change is to keep the consistent charging for such a case.

I agree we should uncharge, but looking at the API name, it seems to
be for kmem pages, why are we not using mem_cgroup_uncharge()? Am I missing
something?

Balbir Singh.