Commit b33e1044 authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds
Browse files

mm/list_lru.c: revert "mm/list_lru: optimize memcg_reparent_list_lru_node()" 



Commit 405cc51f ("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: 405cc51f ("mm/list_lru: optimize memcg_reparent_list_lru_node()")
Acked-by: default avatarShakeel Butt <shakeelb@google.com>
Reviewed-by: default avatarMuchun Song <songmuchun@bytedance.com>
Acked-by: default avatarMichal 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0347b2b9

mm/list_lru.c

+0 −6
Original line number Diff line number Diff line
@@ -394,12 +394,6 @@ static void memcg_reparent_list_lru_node(struct list_lru *lru, int nid, 
	int dst_idx = dst_memcg->kmemcg_id;

	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.