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.
CC: Mel Gorman <mgorman@xxxxxxx>
CC: Johannes Weiner <jweiner@xxxxxxxxxx>
CC: Rik van Riel <riel@xxxxxxxxxx>
Signed-off-by: Minchan Kim <minchan.kim@xxxxxxxxx>
---
mm/compaction.c | 10 +++++++---
1 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/mm/compaction.c b/mm/compaction.c
index 0e572d1..bb3a209 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;
}
/*
--
1.7.6
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