From: Bo Zhang With GFP_NOIO, we cannot reclaim anon folios unless they are in the swap cache. CLRU skips anon reclaim when the swap cache is very low by commit 74d9aa0d8e98 ("mm: vmscan: avoid anon scanning for GFP_NOIO with low swapcache"). Apply the same logic to MGLRU. The new scan-budget-based mechanism makes this straightforward to implement. Thanks also to Xiang Liu, who previously attempted to fix this before we had the scan-budget-based model [1]. [1] https://lore.kernel.org/linux-mm/179248830836.1744016.8424217811286616919.noio-mglru-rfc-v2@bytedance.com/ Cc: Xiang Liu Signed-off-by: Bo Zhang Co-developed-by: Barry Song (Xiaomi) Signed-off-by: Barry Song (Xiaomi) Reviewed-by: Kunwu Chan --- mm/vmscan.c | 27 ++++++++++----------------- 1 file changed, 10 insertions(+), 17 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index d51303a5cb67..9f759d213614 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -272,13 +272,6 @@ static inline bool reclaimable_anon_is_low(struct mem_cgroup *memcg, if (!sc || (sc->gfp_mask & __GFP_IO)) return false; - /* - * FIXME: MGLRU doesn't fully respect can_reclaim_anon_pages() for the - * scanning type, so only apply this to the traditional LRU for now. - */ - if (lru_gen_enabled()) - return false; - if (memcg) { struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat); @@ -4212,6 +4205,8 @@ static void lruvec_evictable_size(struct lruvec *lruvec, struct scan_control *sc int type; unsigned long seq; struct lru_gen_folio *lrugen = &lruvec->lrugen; + struct mem_cgroup *memcg = lruvec_memcg(lruvec); + int nid = lruvec_pgdat(lruvec)->node_id; DEFINE_MAX_SEQ(lruvec); DEFINE_MIN_SEQ(lruvec); @@ -4219,6 +4214,8 @@ static void lruvec_evictable_size(struct lruvec *lruvec, struct scan_control *sc nr[LRU_GEN_FILE] = 0; for_each_evictable_type(type, swappiness) { + if (type == LRU_GEN_ANON && !can_reclaim_anon_pages(memcg, nid, sc)) + continue; for (seq = min_seq[type]; seq <= max_seq; seq++) nr[type] += lruvec_gen_size(lrugen, type, seq, sc->reclaim_idx + 1); } @@ -4893,23 +4890,19 @@ static void lru_gen_balance_scan(struct lruvec *lruvec, struct scan_control *sc, { struct lru_gen_folio *lrugen = &lruvec->lrugen; u64 refault_rate[ANON_AND_FILE], anon_factor, file_factor; - u64 anon_scan, file_scan, total; + u64 anon_scan, file_scan; u64 anon_weight, file_weight; int size_bias; - total = nr[LRU_GEN_ANON] + nr[LRU_GEN_FILE]; - if (!total) - return; - - if (swappiness <= MIN_SWAPPINESS) { + if (swappiness <= MIN_SWAPPINESS) nr[LRU_GEN_ANON] = 0; - nr[LRU_GEN_FILE] = min_t(u64, total_scan, nr[LRU_GEN_FILE]); - return; - } - if (swappiness == SWAPPINESS_ANON_ONLY) { + if (swappiness == SWAPPINESS_ANON_ONLY) nr[LRU_GEN_FILE] = 0; + + if (!nr[LRU_GEN_ANON] || !nr[LRU_GEN_FILE]) { nr[LRU_GEN_ANON] = min_t(u64, total_scan, nr[LRU_GEN_ANON]); + nr[LRU_GEN_FILE] = min_t(u64, total_scan, nr[LRU_GEN_FILE]); return; } -- 2.34.1