diff options
| -rw-r--r-- | include/linux/mmzone.h | 5 | ||||
| -rw-r--r-- | mm/page_alloc.c | 4 | ||||
| -rw-r--r-- | mm/vmscan.c | 60 |
3 files changed, 34 insertions, 35 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 217bcf6bca77..29312bdf119f 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -273,11 +273,6 @@ struct zone_reclaim_stat { */ unsigned long recent_rotated[2]; unsigned long recent_scanned[2]; - - /* - * accumulated for batching - */ - unsigned long nr_saved_scan[NR_LRU_LISTS]; }; struct zone { diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 2a00f17c3bf4..a4e1db3f1981 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4323,10 +4323,8 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat, zone->zone_pgdat = pgdat; zone_pcp_init(zone); - for_each_lru(l) { + for_each_lru(l) INIT_LIST_HEAD(&zone->lru[l].list); - zone->reclaim_stat.nr_saved_scan[l] = 0; - } zone->reclaim_stat.recent_rotated[0] = 0; zone->reclaim_stat.recent_rotated[1] = 0; zone->reclaim_stat.recent_scanned[0] = 0; diff --git a/mm/vmscan.c b/mm/vmscan.c index b0875871820d..2e8fbacd8744 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1718,26 +1718,6 @@ static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan, } /* - * Smallish @nr_to_scan's are deposited in @nr_saved_scan, - * until we collected @swap_cluster_max pages to scan. - */ -static unsigned long nr_scan_try_batch(unsigned long nr_to_scan, - unsigned long *nr_saved_scan) -{ - unsigned long nr; - - *nr_saved_scan += nr_to_scan; - nr = *nr_saved_scan; - - if (nr >= SWAP_CLUSTER_MAX) - *nr_saved_scan = 0; - else - nr = 0; - - return nr; -} - -/* * Determine how aggressively the anon and file LRU lists should be * scanned. The relative value of each set of LRU lists is determined * by looking at the fraction of the pages scanned we did rotate back @@ -1755,6 +1735,22 @@ static void get_scan_count(struct zone *zone, struct scan_control *sc, u64 fraction[2], denominator; enum lru_list l; int noswap = 0; + int force_scan = 0; + + + anon = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_ANON) + + zone_nr_lru_pages(zone, sc, LRU_INACTIVE_ANON); + file = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_FILE) + + zone_nr_lru_pages(zone, sc, LRU_INACTIVE_FILE); + + if (((anon + file) >> priority) < SWAP_CLUSTER_MAX) { + /* kswapd does zone balancing and need to scan this zone */ + if (scanning_global_lru(sc) && current_is_kswapd()) + force_scan = 1; + /* memcg may have small limit and need to avoid priority drop */ + if (!scanning_global_lru(sc)) + force_scan = 1; + } /* If we have no swap space, do not bother scanning anon pages. */ if (!sc->may_swap || (nr_swap_pages <= 0)) { @@ -1765,11 +1761,6 @@ static void get_scan_count(struct zone *zone, struct scan_control *sc, goto out; } - anon = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_ANON) + - zone_nr_lru_pages(zone, sc, LRU_INACTIVE_ANON); - file = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_FILE) + - zone_nr_lru_pages(zone, sc, LRU_INACTIVE_FILE); - if (scanning_global_lru(sc)) { free = zone_page_state(zone, NR_FREE_PAGES); /* If we have very few page cache pages, @@ -1836,8 +1827,23 @@ out: scan >>= priority; scan = div64_u64(scan * fraction[file], denominator); } - nr[l] = nr_scan_try_batch(scan, - &reclaim_stat->nr_saved_scan[l]); + + /* + * If zone is small or memcg is small, nr[l] can be 0. + * This results no-scan on this priority and priority drop down. + * For global direct reclaim, it can visit next zone and tend + * not to have problems. For global kswapd, it's for zone + * balancing and it need to scan a small amounts. When using + * memcg, priority drop can cause big latency. So, it's better + * to scan small amount. See may_noscan above. + */ + if (!scan && force_scan) { + if (file) + scan = SWAP_CLUSTER_MAX; + else if (!noswap) + scan = SWAP_CLUSTER_MAX; + } + nr[l] = scan; } } |