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| author |   Roman Gushchin <roman.gushchin@linux.dev> | 2022-07-01 20:35:21 -0700 |
|---|---|---|
| committer |   akpm <akpm@linux-foundation.org> | 2022-07-29 18:07:14 -0700 |
| commit | d6e103a757fa7876e7ded76128d5dffe12402ab9 (patch) | |
| tree | 5ea391af7dacedee1b69273a4f5f1eb5edb74826 /mm/memcontrol.c | |
| parent | filemap: minor cleanup for filemap_write_and_wait_range (diff) | |
| download | linux-dev-d6e103a757fa7876e7ded76128d5dffe12402ab9.tar.xz linux-dev-d6e103a757fa7876e7ded76128d5dffe12402ab9.zip | |
mm: memcontrol: do not miss MEMCG_MAX events for enforced allocations
Yafang Shao reported an issue related to the accounting of bpf memory:
if a bpf map is charged indirectly for memory consumed from an
interrupt context and allocations are enforced, MEMCG_MAX events are
not raised.
It's not/less of an issue in a generic case because consequent
allocations from a process context will trigger the direct reclaim and
MEMCG_MAX events will be raised. However a bpf map can belong to a
dying/abandoned memory cgroup, so there will be no allocations from a
process context and no MEMCG_MAX events will be triggered.
Link: https://lkml.kernel.org/r/20220702033521.64630-1-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Reported-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index c5bfb3eacd08..767f49a6b987 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2577,6 +2577,7 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask, bool passed_oom = false; bool may_swap = true; bool drained = false; + bool raised_max_event = false; unsigned long pflags; retry: @@ -2616,6 +2617,7 @@ retry: goto nomem; memcg_memory_event(mem_over_limit, MEMCG_MAX); + raised_max_event = true; psi_memstall_enter(&pflags); nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages, @@ -2683,6 +2685,13 @@ nomem: return -ENOMEM; force: /* + * If the allocation has to be enforced, don't forget to raise + * a MEMCG_MAX event. + */ + if (!raised_max_event) + memcg_memory_event(mem_over_limit, MEMCG_MAX); + + /* * The allocation either can't fail or will lead to more memory * being freed very soon. Allow memory usage go over the limit * temporarily by force charging it. |