Re: [next -v1 3/5] memcg: simplify the mem_cgroup_update_lru_size function

[Shakeel Butt]

On Fri, Dec 06, 2024 at 12:24:54AM -0800, Hugh Dickins wrote:
[...]
> Another thing to understand: it's called before adding folio to list,
> but after removing folio from list: when it can usefully compare whether
> the emptiness of the list correctly matches lru_size 0.

I think one source of confusion might be that this "emptiness" check has
been removed by commit b4536f0c829c because of maintaining the list size
per-zone and actual list is shared between zones of a node.

> It cannot do so
> when adding if you "simplify" it in the way that you did.
>