From: Hugh Dickins <hughd@xxxxxxxxxx> Subject: 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 <hughd@xxxxxxxxxx> Reviewed-by: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx> Acked-by: Roman Gushchin <guro@xxxxxx> Acked-by: Chris Down <chris@xxxxxxxxxxxxxx> Reviewed-by: Baoquan He <bhe@xxxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Cc: Hui Su <sh_def@xxxxxxx> Cc: Lorenzo Stoakes <lstoakes@xxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Shakeel Butt <shakeelb@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/memcontrol.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/include/linux/memcontrol.h~mm-memcontrol-fix-warning-in-mem_cgroup_page_lruvec +++ a/include/linux/memcontrol.h @@ -665,7 +665,7 @@ static inline struct lruvec *mem_cgroup_ { 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); } _
