Messages in this thread Patch in this message | | | From | Muchun Song <> | Subject | [PATCH] mm: list_lru: remove holding lru lock | Date | Mon, 25 Oct 2021 20:45:34 +0800 |
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Since commit e5bc3af7734f ("rcu: Consolidate PREEMPT and !PREEMPT synchronize_rcu()"), the critical section of spin lock can serve as an RCU read-side critical section which already allows readers that hold nlru->lock avoid taking rcu lock. So just to remove holding lock.
Signed-off-by: Muchun Song <songmuchun@bytedance.com> --- mm/list_lru.c | 11 ----------- 1 file changed, 11 deletions(-)
diff --git a/mm/list_lru.c b/mm/list_lru.c index 2bba1cd68bb3..7572f8e70b86 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -401,18 +401,7 @@ static int memcg_update_list_lru_node(struct list_lru_node *nlru, } memcpy(&new->lru, &old->lru, flex_array_size(new, lru, old_size)); - - /* - * 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
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