diff mbox series

[8/9] mm/list_lru.c: revert "mm/list_lru: optimize memcg_reparent_list_lru_node()"

Message ID 20220408200914.7C6C3C385A3@smtp.kernel.org (mailing list archive)
State New
Headers show
Series [1/9] mm: migrate: use thp_order instead of HPAGE_PMD_ORDER for new page allocation. | expand

Commit Message

Andrew Morton April 8, 2022, 8:09 p.m. UTC 
From: Andrew Morton <akpm@linux-foundation.org>
Subject: mm/list_lru.c: revert "mm/list_lru: optimize memcg_reparent_list_lru_node()"

405cc51fc1049c73 ("mm/list_lru: optimize memcg_reparent_list_lru_node()")
has subtle races which are proving ugly to fix.  Revert the original
optimization.  If quantitative testing indicates that we have a
significant problem here then other implementations can be looked at.

Fixes: 405cc51fc1049c73 ("mm/list_lru: optimize memcg_reparent_list_lru_node()")
Acked-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/list_lru.c |    6 ------
 1 file changed, 6 deletions(-)
diff mbox series

Patch

--- a/mm/list_lru.c~mm-list_lruc-revert-mm-list_lru-optimize-memcg_reparent_list_lru_node
+++ a/mm/list_lru.c
@@ -395,12 +395,6 @@  static void memcg_reparent_list_lru_node
 	struct list_lru_one *src, *dst;
 
 	/*
-	 * If there is no lru entry in this nlru, we can skip it immediately.
-	 */
-	if (!READ_ONCE(nlru->nr_items))
-		return;
-
-	/*
 	 * Since list_lru_{add,del} may be called under an IRQ-safe lock,
 	 * we have to use IRQ-safe primitives here to avoid deadlock.
 	 */