From 7ea510b92c7c9b4eb5ff72e6b4bbad4b0407a914 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Tue, 12 Jan 2021 15:49:11 -0800 Subject: [PATCH] mm/memcontrol: fix warning in mem_cgroup_page_lruvec() Boot a CONFIG_MEMCG=y kernel with "cgroup_disabled=memory" and you are met by a series of warnings from the VM_WARN_ON_ONCE_PAGE(!memcg, page) recently added to the inline mem_cgroup_page_lruvec(). An earlier attempt to place that warning, in mem_cgroup_lruvec(), had been careful to do so after weeding out the mem_cgroup_disabled() case; but was itself invalid because of the mem_cgroup_lruvec(NULL, pgdat) in clear_pgdat_congested() and age_active_anon(). Warning in mem_cgroup_page_lruvec() was once useful in detecting a KSM charge bug, so may be worth keeping: but skip if mem_cgroup_disabled(). Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2101032056260.1093@eggly.anvils Fixes: 9a1ac2288cf1 ("mm/memcontrol:rewrite mem_cgroup_page_lruvec()") Signed-off-by: Hugh Dickins Reviewed-by: Alex Shi Acked-by: Roman Gushchin Acked-by: Chris Down Reviewed-by: Baoquan He Acked-by: Vlastimil Babka Cc: Hui Su Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Johannes Weiner Cc: Shakeel Butt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index d827bd7f3bfe..eeb0b52203e9 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -665,7 +665,7 @@ static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page, { struct mem_cgroup *memcg = page_memcg(page); - VM_WARN_ON_ONCE_PAGE(!memcg, page); + VM_WARN_ON_ONCE_PAGE(!memcg && !mem_cgroup_disabled(), page); return mem_cgroup_lruvec(memcg, pgdat); }