From de7e68e5830ea4bcddd2b592202b352a1f961c60 Mon Sep 17 00:00:00 2001 From: Minchan Kim Date: Wed, 28 Sep 2011 10:50:19 +1000 Subject: [PATCH] mm: compaction: accounting fix I saw the following accouting of compaction during test of the series. compact_blocks_moved 251 compact_pages_moved 44 It's very awkward to me although it's possbile because it means we try to compact 251 blocks but it just migrated 44 pages. As further investigation, I found isolate_migratepages doesn't isolate any pages but it returns ISOLATE_SUCCESS and then, it just increases compact_blocks_moved but doesn't increased compact_pages_moved. This patch makes accouting of compaction works only in case of success of isolation. Signed-off-by: Minchan Kim Cc: Mel Gorman Acked-by: Johannes Weiner Cc: Rik van Riel Signed-off-by: Andrew Morton <> --- mm/compaction.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/mm/compaction.c b/mm/compaction.c index 12c3b62e814e..167c8800da60 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -260,6 +260,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, unsigned long low_pfn, end_pfn; unsigned long last_pageblock_nr = 0, pageblock_nr; unsigned long nr_scanned = 0, nr_isolated = 0; + isolate_migrate_t ret = ISOLATE_NONE; struct list_head *migratelist = &cc->migratepages; isolate_mode_t mode = ISOLATE_ACTIVE | ISOLATE_INACTIVE | ISOLATE_UNEVICTABLE; @@ -273,7 +274,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, /* Do not cross the free scanner or scan within a memory hole */ if (end_pfn > cc->free_pfn || !pfn_valid(low_pfn)) { cc->migrate_pfn = end_pfn; - return ISOLATE_NONE; + return ret; } /* @@ -370,14 +371,17 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, break; } - acct_isolated(zone, cc); + if (cc->nr_migratepages > 0) { + acct_isolated(zone, cc); + ret = ISOLATE_SUCCESS; + } spin_unlock_irq(&zone->lru_lock); cc->migrate_pfn = low_pfn; trace_mm_compaction_isolate_migratepages(nr_scanned, nr_isolated); - return ISOLATE_SUCCESS; + return ret; } /* -- 2.39.5