Since commit e5bc3af7734f ("rcu: Consolidate PREEMPT and !PREEMPT
synchronize_rcu()"), the critical section of spinlock can serve
as RCU read-side critical section. So we can remove redundant
locking from memcg_update_list_lru_node().
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
---
mm/list_lru.c | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)
diff --git a/mm/list_lru.c b/mm/list_lru.c
index 4962d48d4410..e86d4d055d3c 100644
--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -403,18 +403,9 @@ static int memcg_update_list_lru_node(struct list_lru_node *nlru,
memcpy(&new->lru, &old->lru, old_size * sizeof(void *));
- /*
- * The locking below allows readers that hold nlru->lock avoid taking
- * rcu_read_lock (see list_lru_from_memcg_idx).
- *
- * Since list_lru_{add,del} may be called under an IRQ-safe lock,
- * we have to use IRQ-safe primitives here to avoid deadlock.
- */
- spin_lock_irq(&nlru->lock);
rcu_assign_pointer(nlru->memcg_lrus, new);
- spin_unlock_irq(&nlru->lock);
-
kvfree_rcu(old, rcu);
+
return 0;
}
--
2.11.0
