The patch titled
Subject: mm: memcontrol: fix get_active_memcg return value
has been added to the -mm tree. Its filename is
mm-memcontrol-fix-get_active_memcg-return-value.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-memcontrol-fix-get_active_memcg-return-value.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-memcontrol-fix-get_active_memcg-return-value.patch
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------------------------------------------------------
From: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Subject: mm: memcontrol: fix get_active_memcg return value
We use a global percpu int_active_memcg variable to store the remote memcg
when we are in the interrupt context. But get_active_memcg always return
the current->active_memcg or root_mem_cgroup. The remote memcg (set in
the interrupt context) is ignored. This is not what we want. So fix it.
Link: https://lkml.kernel.org/r/20210223091101.42150-1-songmuchun@xxxxxxxxxxxxx
Fixes: 37d5985c003d ("mm: kmem: prepare remote memcg charging infra for interrupt contexts")
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Reviewed-by: Roman Gushchin <guro@xxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
--- a/mm/memcontrol.c~mm-memcontrol-fix-get_active_memcg-return-value
+++ a/mm/memcontrol.c
@@ -1061,13 +1061,9 @@ static __always_inline struct mem_cgroup
rcu_read_lock();
memcg = active_memcg();
- if (memcg) {
- /* current->active_memcg must hold a ref. */
- if (WARN_ON_ONCE(!css_tryget(&memcg->css)))
- memcg = root_mem_cgroup;
- else
- memcg = current->active_memcg;
- }
+ /* remote memcg must hold a ref. */
+ if (memcg && WARN_ON_ONCE(!css_tryget(&memcg->css)))
+ memcg = root_mem_cgroup;
rcu_read_unlock();
return memcg;
_
Patches currently in -mm which might be from songmuchun@xxxxxxxxxxxxx are
mm-memcontrol-optimize-per-lruvec-stats-counter-memory-usage.patch
mm-memcontrol-fix-nr_anon_thps-accounting-in-charge-moving.patch
mm-memcontrol-convert-nr_anon_thps-account-to-pages.patch
mm-memcontrol-convert-nr_file_thps-account-to-pages.patch
mm-memcontrol-convert-nr_shmem_thps-account-to-pages.patch
mm-memcontrol-convert-nr_shmem_pmdmapped-account-to-pages.patch
mm-memcontrol-convert-nr_file_pmdmapped-account-to-pages.patch
mm-memcontrol-make-the-slab-calculation-consistent.patch
mm-memcontrol-replace-the-loop-with-a-list_for_each_entry.patch
mm-memcontrol-fix-swap-undercounting-in-cgroup2.patch
mm-memcontrol-fix-get_active_memcg-return-value.patch
hugetlb-convert-page_huge_active-hpagemigratable-flag-fix.patch
