Re: [PATCH] memcg: add per-memcg vmalloc stat

[Shakeel Butt]

On Tue, Dec 21, 2021 at 8:15 PM Muchun Song <songmuchun@xxxxxxxxxxxxx> wrote:
>
[...]
> > +static inline void mod_memcg_page_state(struct page *page,
> > +                                       int idx, int val)
> > +{
> > +       struct mem_cgroup *memcg = page_memcg(page);
> > +
> > +       if (!mem_cgroup_disabled() && memcg)
> > +               mod_memcg_state(memcg, idx, val);
>
> It's not safe to access @memcg throughout mod_memcg_state() for the
> kmem charged through objcg infrastructure. It's supposed to be safe
> to access @memcg under rcu read lock. Otherwise, it looks good to
> me.

Indeed you are right. v2 coming.