From 6e08a369ee10b361ac1cdcdf4fabd420fd08beb3 Mon Sep 17 00:00:00 2001 From: Wu Fengguang Date: Tue, 16 Jun 2009 15:32:29 -0700 Subject: vmscan: cleanup the scan batching code The vmscan batching logic is twisting. Move it into a standalone function nr_scan_try_batch() and document it. No behavior change. Signed-off-by: Wu Fengguang Acked-by: Rik van Riel Cc: Nick Piggin Cc: Christoph Lameter Acked-by: Peter Zijlstra Acked-by: KOSAKI Motohiro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmscan.c | 39 ++++++++++++++++++++++++++++----------- 1 file changed, 28 insertions(+), 11 deletions(-) (limited to 'mm/vmscan.c') diff --git a/mm/vmscan.c b/mm/vmscan.c index 9673437..d4da097 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1492,6 +1492,26 @@ static void get_scan_ratio(struct zone *zone, struct scan_control *sc, percent[1] = 100 - percent[0]; } +/* + * 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 swap_cluster_max) +{ + 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; +} /* * This is a basic per-zone page freer. Used by both kswapd and direct reclaim. @@ -1517,14 +1537,11 @@ static void shrink_zone(int priority, struct zone *zone, scan >>= priority; scan = (scan * percent[file]) / 100; } - if (scanning_global_lru(sc)) { - zone->lru[l].nr_scan += scan; - nr[l] = zone->lru[l].nr_scan; - if (nr[l] >= swap_cluster_max) - zone->lru[l].nr_scan = 0; - else - nr[l] = 0; - } else + if (scanning_global_lru(sc)) + nr[l] = nr_scan_try_batch(scan, + &zone->lru[l].nr_saved_scan, + swap_cluster_max); + else nr[l] = scan; } @@ -2124,11 +2141,11 @@ static void shrink_all_zones(unsigned long nr_pages, int prio, l == LRU_ACTIVE_FILE)) continue; - zone->lru[l].nr_scan += (lru_pages >> prio) + 1; - if (zone->lru[l].nr_scan >= nr_pages || pass > 3) { + zone->lru[l].nr_saved_scan += (lru_pages >> prio) + 1; + if (zone->lru[l].nr_saved_scan >= nr_pages || pass > 3) { unsigned long nr_to_scan; - zone->lru[l].nr_scan = 0; + zone->lru[l].nr_saved_scan = 0; nr_to_scan = min(nr_pages, lru_pages); nr_reclaimed += shrink_list(l, nr_to_scan, zone, sc, prio); -- cgit v1.1