From: lyugaofei It has been observed that swappiness=200 can significantly slow down reclaim on some machines, with some workloads running 3x slower under MGLRU than under CLRU. This is because swappiness=200 currently results in file_factor=0. Give file reclaim a small factor at lower priorities, for example, when sc->priority < DEF_PRIORITY / 2. Signed-off-by: lyugaofei Co-developed-by: Barry Song (Xiaomi) Signed-off-by: Barry Song (Xiaomi) --- mm/vmscan.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 6315edf50376..3872305bac2a 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4888,8 +4888,8 @@ static int get_tier_idx(struct lruvec *lruvec, int type) * We don't calculate the scan cost, MGLRU uses lazy promotion, which will * cancel the scan budget natually. */ -static void lru_gen_balance_scan(struct lruvec *lruvec, int swappiness, - unsigned long total_scan, unsigned long nr[]) +static void lru_gen_balance_scan(struct lruvec *lruvec, struct scan_control *sc, + int swappiness, unsigned long total_scan, unsigned long nr[]) { struct lru_gen_folio *lrugen = &lruvec->lrugen; u64 refault_rate[ANON_AND_FILE], anon_factor, file_factor; @@ -4946,7 +4946,12 @@ static void lru_gen_balance_scan(struct lruvec *lruvec, int swappiness, file_weight = nr[LRU_GEN_FILE] + nr[LRU_GEN_ANON] / size_bias; anon_factor = (u64)swappiness * refault_rate[LRU_GEN_FILE] * anon_weight; - file_factor = (u64)(MAX_SWAPPINESS - swappiness) * refault_rate[LRU_GEN_ANON] * file_weight; + if (swappiness == MAX_SWAPPINESS) + file_factor = sc->priority < DEF_PRIORITY / 2 ? + refault_rate[LRU_GEN_ANON] * file_weight : 0; + else + file_factor = (u64)(MAX_SWAPPINESS - swappiness) * + refault_rate[LRU_GEN_ANON] * file_weight; /* Cross-multiply the ratio above. */ anon_scan = mul_u64_u64_div_u64(total_scan, anon_factor, anon_factor + file_factor); @@ -5143,7 +5148,7 @@ static void lru_gen_prepare_scan(struct lruvec *lruvec, struct scan_control *sc, total = apply_proportional_protection(memcg, sc, total); total >>= sc->priority; - lru_gen_balance_scan(lruvec, swappiness, total, nr_to_scan); + lru_gen_balance_scan(lruvec, sc, swappiness, total, nr_to_scan); } static bool should_abort_scan(struct lruvec *lruvec, struct scan_control *sc) @@ -5890,7 +5895,7 @@ static int run_eviction(struct lruvec *lruvec, unsigned long seq, struct scan_co return 0; lruvec_evictable_size(lruvec, sc, swappiness, nr_to_scan); - lru_gen_balance_scan(lruvec, swappiness, + lru_gen_balance_scan(lruvec, sc, swappiness, nr_to_reclaim - sc->nr_reclaimed, nr_to_scan); if (!evict_folio_lists(nr_to_scan, lruvec, sc, swappiness, MAX_LRU_BATCH)) -- 2.34.1