The quilt patch titled
Subject: mm: memcontrol: do not miss MEMCG_MAX events for enforced allocations
has been removed from the -mm tree. Its filename was
mm-memcontrol-do-not-miss-memcg_max-events-for-enforced-allocations.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Subject: mm: memcontrol: do not miss MEMCG_MAX events for enforced allocations
Date: Fri, 1 Jul 2022 20:35:21 -0700
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@xxxxxxxxx
Signed-off-by: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Reported-by: Yafang Shao <laoar.shao@xxxxxxxxx>
Acked-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 9 +++++++++
1 file changed, 9 insertions(+)
--- a/mm/memcontrol.c~mm-memcontrol-do-not-miss-memcg_max-events-for-enforced-allocations
+++ a/mm/memcontrol.c
@@ -2577,6 +2577,7 @@ static int try_charge_memcg(struct mem_c
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.
_
Patches currently in -mm which might be from roman.gushchin@xxxxxxxxx are
