Re: [PATCH v4 4/4] mm: convert page kmemcg type to a page memcg flag

[Johannes Weiner]

On Fri, Oct 02, 2020 at 12:03:50PM +0200, Michal Koutný wrote:
> On Thu, Oct 01, 2020 at 01:27:13PM -0400, Johannes Weiner <hannes@xxxxxxxxxxx> wrote:
> > I do think there is a bug, though: mem_cgroup_move_account() should
> > use WRITE_ONCE() on page->mem_cgroup.
> If this were a bug, wouldn't be the proper approach
> rcu_assign_pointer()/rcu_dereference() pair?

Yes, you're right.

I'll double check these code paths and follow up with a patch if
necessary.