[PATCH 05/17] mm: list_lru: remove holding lru node lock
From: Muchun Song <hidden>
Date: 2021-05-11 10:51:54
Also in:
linux-fsdevel, linux-nfs, lkml
Subsystem:
memory management, shrinker, the rest · Maintainers:
Andrew Morton, Dave Chinner, Linus Torvalds
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 <redacted>
---
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