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Howlett" , Usama Arif , Kiryl Shutsemau , Vlastimil Babka , Kairui Song , Mikhail Zaslonko , Vasily Gorbik , Baolin Wang , Barry Song , Dev Jain , Lance Yang , Nico Pache , Ryan Roberts , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v5 2/9] mm: list_lru: lock_list_lru_of_memcg() cannot return NULL if !skip_empty Date: Wed, 27 May 2026 16:45:09 -0400 Message-ID: <20260527204757.2544958-3-hannes@cmpxchg.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260527204757.2544958-1-hannes@cmpxchg.org> References: <20260527204757.2544958-1-hannes@cmpxchg.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit skip_empty is only for the shrinker to abort and skip a list that's empty or whose cgroup is being deleted. For list additions and deletions, the cgroup hierarchy is walked upwards until a valid list_lru head is found, or it will fall back to the node list. Acquiring the lock won't fail. Remove the NULL checks in those callers. Reviewed-by: David Hildenbrand (Arm) Acked-by: Shakeel Butt Reviewed-by: Lorenzo Stoakes (Oracle) Signed-off-by: Johannes Weiner Reviewed-by: Liam R. Howlett (Oracle) --- mm/list_lru.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/mm/list_lru.c b/mm/list_lru.c index 45d1b97737ea..77999ed78fa5 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -165,8 +165,6 @@ bool list_lru_add(struct list_lru *lru, struct list_head *item, int nid, struct list_lru_one *l; l = lock_list_lru_of_memcg(lru, nid, &memcg, false, false); - if (!l) - return false; if (list_empty(item)) { list_add_tail(item, &l->list); /* @@ -208,9 +206,8 @@ bool list_lru_del(struct list_lru *lru, struct list_head *item, int nid, { struct list_lru_node *nlru = &lru->node[nid]; struct list_lru_one *l; + l = lock_list_lru_of_memcg(lru, nid, &memcg, false, false); - if (!l) - return false; if (!list_empty(item)) { list_del_init(item); l->nr_items--; -- 2.54.0