From: Muchun Song <songmuchun@bytedance.com>
To: willy@infradead.org, akpm@linux-foundation.org,
hannes@cmpxchg.org, mhocko@kernel.org, vdavydov.dev@gmail.com,
shakeelb@google.com, guro@fb.com, shy828301@gmail.com,
alexs@kernel.org, alexander.h.duyck@linux.intel.com,
richard.weiyang@gmail.com
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, Muchun Song <songmuchun@bytedance.com>
Subject: [PATCH 1/9] mm: list_lru: fix list_lru_count_one() return value
Date: Wed, 28 Apr 2021 17:49:41 +0800 [thread overview]
Message-ID: <20210428094949.43579-2-songmuchun@bytedance.com> (raw)
In-Reply-To: <20210428094949.43579-1-songmuchun@bytedance.com>
Since commit 2788cf0c401c ("memcg: reparent list_lrus and free kmemcg_id
on css offline"), the ->nr_items can be negative during memory cgroup
reparenting. In this case, list_lru_count_one() can returns an unusually
large value. In order to not surprise the user. So return zero when
->nr_items is negative.
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
mm/list_lru.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/mm/list_lru.c b/mm/list_lru.c
index cd58790d0fb3..4962d48d4410 100644
--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -176,13 +176,16 @@ unsigned long list_lru_count_one(struct list_lru *lru,
{
struct list_lru_node *nlru = &lru->node[nid];
struct list_lru_one *l;
- unsigned long count;
+ long count;
rcu_read_lock();
l = list_lru_from_memcg_idx(nlru, memcg_cache_id(memcg));
count = READ_ONCE(l->nr_items);
rcu_read_unlock();
+ if (unlikely(count < 0))
+ count = 0;
+
return count;
}
EXPORT_SYMBOL_GPL(list_lru_count_one);
--
2.11.0
next prev parent reply other threads:[~2021-04-28 9:54 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-28 9:49 [PATCH 0/9] Shrink the list lru size on memory cgroup removal Muchun Song
2021-04-28 9:49 ` Muchun Song [this message]
2021-04-28 9:49 ` [PATCH 2/9] mm: memcontrol: remove kmemcg_id reparenting Muchun Song
2021-04-28 9:49 ` [PATCH 3/9] mm: list_lru: rename memcg_drain_all_list_lrus to memcg_reparent_list_lrus Muchun Song
2021-04-28 9:49 ` [PATCH 4/9] mm: memcontrol: remove the kmem states Muchun Song
2021-04-28 9:49 ` [PATCH 5/9] mm: memcontrol: move memcg_online_kmem() to mem_cgroup_css_online() Muchun Song
2021-04-28 9:49 ` [PATCH 6/9] mm: list_lru: support for shrinking list lru Muchun Song
2021-04-28 9:49 ` [PATCH 7/9] ida: introduce ida_max() to return the maximum allocated ID Muchun Song
2021-04-29 6:47 ` Christoph Hellwig
2021-04-29 7:36 ` [External] " Muchun Song
2021-04-28 9:49 ` [PATCH 8/9] mm: memcontrol: shrink the list lru size Muchun Song
2021-04-28 9:49 ` [PATCH 9/9] mm: memcontrol: rename memcg_{get,put}_cache_ids to memcg_list_lru_resize_{lock,unlock} Muchun Song
2021-04-28 23:32 ` [PATCH 0/9] Shrink the list lru size on memory cgroup removal Shakeel Butt
2021-04-29 3:05 ` [External] " Muchun Song
2021-04-30 0:49 ` Dave Chinner
2021-04-30 1:39 ` Roman Gushchin
2021-04-30 3:27 ` Dave Chinner
2021-04-30 8:32 ` [External] " Muchun Song
2021-05-01 3:10 ` Roman Gushchin
2021-05-01 3:27 ` Matthew Wilcox
2021-05-02 23:58 ` Dave Chinner
2021-05-03 6:33 ` Muchun Song
2021-05-05 1:13 ` Dave Chinner
2021-05-07 5:45 ` Muchun Song
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