From: Yue Zhao <findns94@gmail.com>
To: linux-mm@kvack.org
Cc: akpm@linux-foundation.org, roman.gushchin@linux.dev,
hannes@cmpxchg.org, mhocko@kernel.org, shakeelb@google.com,
muchun.song@linux.dev, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org, Yue Zhao <findns94@gmail.com>
Subject: [PATCH] mm: change memcg->oom_group access with atomic operations
Date: Mon, 20 Feb 2023 23:16:38 +0800 [thread overview]
Message-ID: <20230220151638.1371-1-findns94@gmail.com> (raw)
The knob for cgroup v2 memory controller: memory.oom.group
will be read and written simultaneously by user space
programs, thus we'd better change memcg->oom_group access
with atomic operations to avoid concurrency problems.
Signed-off-by: Yue Zhao <findns94@gmail.com>
---
mm/memcontrol.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 73afff8062f9..e4695fb80bda 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2057,7 +2057,7 @@ struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim,
* highest-level memory cgroup with oom.group set.
*/
for (; memcg; memcg = parent_mem_cgroup(memcg)) {
- if (memcg->oom_group)
+ if (READ_ONCE(memcg->oom_group))
oom_group = memcg;
if (memcg == oom_domain)
@@ -6569,7 +6569,7 @@ static int memory_oom_group_show(struct seq_file *m, void *v)
{
struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
- seq_printf(m, "%d\n", memcg->oom_group);
+ seq_printf(m, "%d\n", READ_ONCE(memcg->oom_group));
return 0;
}
@@ -6591,7 +6591,7 @@ static ssize_t memory_oom_group_write(struct kernfs_open_file *of,
if (oom_group != 0 && oom_group != 1)
return -EINVAL;
- memcg->oom_group = oom_group;
+ WRITE_ONCE(memcg->oom_group, oom_group);
return nbytes;
}
--
2.17.1
next reply other threads:[~2023-02-20 15:16 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-20 15:16 Yue Zhao [this message]
2023-02-20 21:09 ` [PATCH] mm: change memcg->oom_group access with atomic operations Roman Gushchin
2023-02-20 23:06 ` Shakeel Butt
2023-02-21 5:17 ` Roman Gushchin
2023-02-21 6:52 ` Shakeel Butt
2023-02-21 13:51 ` Matthew Wilcox
2023-02-21 16:56 ` Shakeel Butt
2023-02-21 18:23 ` Paul E. McKenney
2023-02-21 22:23 ` Roman Gushchin
2023-02-21 22:38 ` Paul E. McKenney
2023-02-21 23:13 ` Shakeel Butt
2023-02-21 23:38 ` Paul E. McKenney
2023-02-21 23:57 ` Roman Gushchin
2023-02-22 0:37 ` Paul E. McKenney
2023-02-22 4:28 ` Roman Gushchin
2023-02-21 17:47 ` Roman Gushchin
2023-02-21 18:15 ` Shakeel Butt
2023-02-21 18:18 ` Matthew Wilcox
2023-02-22 9:01 ` David Laight
2023-02-21 17:00 ` Martin Zhao
2023-02-21 7:22 ` Muchun Song
2023-02-21 17:48 ` Roman Gushchin
2023-02-21 17:00 ` Martin Zhao
2023-02-21 18:02 ` Roman Gushchin
2023-02-21 8:26 ` Michal Hocko
2023-02-21 17:00 ` Martin Zhao
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