Re: [PATCH v2] mm: memcontrol: Simplify the mem_cgroup_page_lruvec

[Michal Hocko]

On Thu 29-10-20 09:01:37, Shakeel Butt wrote:
> On Thu, Oct 29, 2020 at 2:08 AM Michal Hocko <mhocko@xxxxxxxx> wrote:
> >
> > On Wed 28-10-20 11:50:13, Muchun Song wrote:
> > [...]
> > > -struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgdat)
> > > +static struct lruvec *
> > > +__mem_cgroup_node_lruvec(struct mem_cgroup *memcg, struct pglist_data *pgdat,
> > > +                      int nid)
> >
> > I thought I have made it clear that this is not a good approach. Please
> > do not repost new version without that being addressed. If there are any
> > questions then feel free to ask for details.
> 
> You can get nid from pgdat (pgdat->node_id) and also pgdat from nid
> (NODE_DATA(nid)), so, __mem_cgroup_node_lruvec() only need one of them
> as parameter.

Exactly what I've said in the previous version review. I suspect that
the issue is that mem_cgroup_page_nodeinfo (based on page's node_id)
and the given pgdat can mismatch in the existing code but that shouldn't
be a real problem because the mismatch can only happen for lruvec->pgdat
== NULL unless I am missing something.

-- 
Michal Hocko
SUSE Labs