On Thu, Jun 10, 2021 at 10:39:43AM -0700, Dan Schatzberg <schatzberg.dan@xxxxxxxxx> wrote:
> @@ -926,8 +937,17 @@ struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
> * counting is disabled on the root level in the
> * cgroup core. See CSS_NO_REF.
> */
> - if (unlikely(!mm))
> - return root_mem_cgroup;
> + if (unlikely(!mm)) {
> + memcg = active_memcg();
> + if (unlikely(memcg)) {
> + /* remote memcg must hold a ref */
> + css_get(&memcg->css);
> + return memcg;
> + }
> + mm = current->mm;
> + if (unlikely(!mm))
> + return root_mem_cgroup;
> + }
With the change in __add_to_page_cache_locked() all page cache charges
will supply null mm, so the first !mm unlikely hint may not be warranted
anymore. Just an interesting point, generally, I'm adding
Reviewed-by: Michal Koutný <mkoutny@xxxxxxxx>
Attachment:
signature.asc
Description: Digital signature
