mm/memcg: fix 5.10 backport of splitting page memcg

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@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Hugh Dickins 2021-03-28 17:13:13 -07:00 committed by Greg Kroah-Hartman
parent 2c163520e1
commit 002ea848d7

View File

@ -3274,13 +3274,17 @@ void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size)
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);
}