| Message ID | 20210223235128.Eey1x63a9%akpm@linux-foundation.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | + mm-memcontrol-fix-get_active_memcg-return-value.patch added to -mm tree | expand |
--- 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;
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 Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Muchun Song <songmuchun@bytedance.com> 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@bytedance.com Fixes: 37d5985c003d ("mm: kmem: prepare remote memcg charging infra for interrupt contexts") Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Roman Gushchin <guro@fb.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> --- mm/memcontrol.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-)