On Sun, Mar 28, 2021 at 05:13:13PM -0700, Hugh Dickins wrote:
> The straight backport of 5.12's e1baddf8475b ("mm/memcg: set memcg when
> splitting page") works fine in 5.11, but turned out to be wrong for 5.10:
> because that relies on a separate flag, which must also be set for the
> memcg to be recognized and uncharged and cleared when freeing. Fix that.
>
> Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
> ---
>
> mm/memcontrol.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -3274,13 +3274,17 @@ void obj_cgroup_uncharge(struct obj_cgro
> void split_page_memcg(struct page *head, unsigned int nr)
> {
> struct mem_cgroup *memcg = head->mem_cgroup;
> + int kmemcg = PageKmemcg(head);
> int i;
>
> if (mem_cgroup_disabled() || !memcg)
> return;
>
> - for (i = 1; i < nr; i++)
> + for (i = 1; i < nr; i++) {
> head[i].mem_cgroup = memcg;
> + if (kmemcg)
> + __SetPageKmemcg(head + i);
> + }
> css_get_many(&memcg->css, nr - 1);
> }
>
Thanks for the fix, now queued up.
greg k-h
