From b35ea17b7bbf5dea35faa0de11030acc620c3197 Mon Sep 17 00:00:00 2001 From: KOSAKI Motohiro Date: Mon, 21 Sep 2009 17:01:36 -0700 Subject: [PATCH] mm: shrink_inactive_list() nr_scan accounting fix fix If sc->isolate_pages() return 0, we don't need to call shrink_page_list(). In past days, shrink_inactive_list() handled it properly. But commit fb8d14e1 (three years ago commit!) breaked it. current shrink_inactive_list() always call shrink_page_list() although isolate_pages() return 0. This patch restore proper return value check. Requirements: o "nr_taken == 0" condition should stay before calling shrink_page_list(). o "nr_taken == 0" condition should stay after nr_scan related statistics modification. Cc: Wu Fengguang Signed-off-by: KOSAKI Motohiro Reviewed-by: Rik van Riel Reviewed-by: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmscan.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 45a150a3a442..d86a91f8c16b 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1076,6 +1076,20 @@ static unsigned long shrink_inactive_list(unsigned long max_scan, nr_taken = sc->isolate_pages(sc->swap_cluster_max, &page_list, &nr_scan, sc->order, mode, zone, sc->mem_cgroup, 0, file); + + if (scanning_global_lru(sc)) { + zone->pages_scanned += nr_scan; + if (current_is_kswapd()) + __count_zone_vm_events(PGSCAN_KSWAPD, zone, + nr_scan); + else + __count_zone_vm_events(PGSCAN_DIRECT, zone, + nr_scan); + } + + if (nr_taken == 0) + goto done; + nr_active = clear_active_flags(&page_list, count); __count_vm_events(PGDEACTIVATE, nr_active); @@ -1088,8 +1102,6 @@ static unsigned long shrink_inactive_list(unsigned long max_scan, __mod_zone_page_state(zone, NR_INACTIVE_ANON, -count[LRU_INACTIVE_ANON]); - if (scanning_global_lru(sc)) - zone->pages_scanned += nr_scan; reclaim_stat->recent_scanned[0] += count[LRU_INACTIVE_ANON]; reclaim_stat->recent_scanned[0] += count[LRU_ACTIVE_ANON]; @@ -1123,18 +1135,12 @@ static unsigned long shrink_inactive_list(unsigned long max_scan, } nr_reclaimed += nr_freed; + local_irq_disable(); - if (current_is_kswapd()) { - __count_zone_vm_events(PGSCAN_KSWAPD, zone, nr_scan); + if (current_is_kswapd()) __count_vm_events(KSWAPD_STEAL, nr_freed); - } else if (scanning_global_lru(sc)) - __count_zone_vm_events(PGSCAN_DIRECT, zone, nr_scan); - __count_zone_vm_events(PGSTEAL, zone, nr_freed); - if (nr_taken == 0) - goto done; - spin_lock(&zone->lru_lock); /* * Put back any unfreeable pages. @@ -1164,9 +1170,9 @@ static unsigned long shrink_inactive_list(unsigned long max_scan, } } } while (nr_scanned < max_scan); - spin_unlock(&zone->lru_lock); + done: - local_irq_enable(); + spin_unlock_irq(&zone->lru_lock); pagevec_release(&pvec); return nr_reclaimed; } -- 2.30.2