From 002ea848d7fd3bdcb6281e75bdde28095c2cd549 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Sun, 28 Mar 2021 17:13:13 -0700 Subject: [PATCH] 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 Signed-off-by: Greg Kroah-Hartman --- mm/memcontrol.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index dda4223d3ff9..d72d2b90474a 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -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); }