From c7a37bac3ccc2732993705d3c3488b278b422ec6 Mon Sep 17 00:00:00 2001 From: Hui Zhu Date: Fri, 11 Sep 2026 16:00:49 +0800 Subject: [PATCH] mm: workingset: use lruvec_page_state_local() to count lru pages Commit 7404bd37cfbe ("mm: workingset: use lruvec_lru_size() to get the number of lru pages") switched count_shadow_nodes() to lruvec_lru_size(). With CONFIG_MEMCG enabled, lruvec_lru_size() reads mz->lru_zone_size, which only the classic LRU paths maintain. MGLRU accounts its pages through __update_lru_size(), which skips that array, so with MGLRU on the four evictable LRU lists are always seen as empty. The shadow node budget (pages >> 3) then collapses to slab plus unevictable pages, and the workingset shadow shrinker reclaims eviction tokens almost as fast as they are created, losing thrashing protection. lruvec_page_state_local() reads lruvec_stats->state_local instead, which both classic LRU and MGLRU maintain. Switch back to it. The reparenting race this re-exposes on cgroup v2 is closed by the preceding patch that redirects dying-memcg stat updates for all hierarchies. Link: https://lore.kernel.org/2ed42f96aca124856ea30f774afb55cbe6d8ba58.1789096175.git.zhuhui@kylinos.cn Fixes: 7404bd37cfbe ("mm: workingset: use lruvec_lru_size() to get the number of lru pages") Signed-off-by: Hui Zhu Signed-off-by: Andrew Morton Acked-by: Shakeel Butt Reviewed-by: Barry Song Reviewed-by: Kairui Song Cc: Axel Rasmussen Cc: David Hildenbrand Cc: Johannes Weiner Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Muchun Song Cc: Roman Gushchin Cc: Wei Xu Cc: Yuanchu Xie Cc: --- mm/workingset.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/mm/workingset.c b/mm/workingset.c index 7ac2b88c80ae..8412f4840ae3 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -688,10 +688,9 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker, mem_cgroup_flush_stats_ratelimited(sc->memcg); lruvec = mem_cgroup_lruvec(sc->memcg, NODE_DATA(sc->nid)); - for (pages = 0, i = 0; i < NR_LRU_LISTS; i++) - pages += lruvec_lru_size(lruvec, i, MAX_NR_ZONES - 1); - + pages += lruvec_page_state_local(lruvec, + NR_LRU_BASE + i); pages += lruvec_page_state_local( lruvec, NR_SLAB_RECLAIMABLE_B) >> PAGE_SHIFT; pages += lruvec_page_state_local(