[PATCH 3/6] mm, compaction: encapsulate resetting cached scanner positions

Vlastimil Babka
2015-06-10T09:33:49Z

Resetting the cached compaction scanner positions is now done implicitly in
__reset_isolation_suitable() and compact_finished(). Encapsulate the
functionality in a new function reset_cached_positions() and call it explicitly
where needed.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
---
mm/compaction.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index 7e0a814..d334bb3 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -207,6 +207,13 @@ static inline bool isolation_suitable(struct compact_control *cc,
return !get_pageblock_skip(page);
}

+static void reset_cached_positions(struct zone *zone)
+{
+ zone->compact_cached_migrate_pfn[0] = zone->zone_start_pfn;
+ zone->compact_cached_migrate_pfn[1] = zone->zone_start_pfn;
+ zone->compact_cached_free_pfn = zone_end_pfn(zone);
+}
+
/*
* This function is called to clear all cached information on pageblocks that
* should be skipped for page isolation when the migrate and free page scanner
@@ -218,9 +225,6 @@ static void __reset_isolation_suitable(struct zone *zone)
unsigned long end_pfn = zone_end_pfn(zone);
unsigned long pfn;

- zone->compact_cached_migrate_pfn[0] = start_pfn;
- zone->compact_cached_migrate_pfn[1] = start_pfn;
- zone->compact_cached_free_pfn = end_pfn;
zone->compact_blockskip_flush = false;

/* Walk the zone and mark every pageblock as suitable for isolation */
@@ -250,8 +254,10 @@ void reset_isolation_suitable(pg_data_t *pgdat)
continue;

/* Only flush if a full compaction finished recently */
- if (zone->compact_blockskip_flush)
+ if (zone->compact_blockskip_flush) {
__reset_isolation_suitable(zone);
+ reset_cached_positions(zone);
+ }
}
}

@@ -1164,9 +1170,7 @@ static int __compact_finished(struct zone *zone, struct compact_control *cc,
/* Compaction run completes if the migrate and free scanner meet */
if (compact_scanners_met(cc)) {
/* Let the next compaction start anew. */
- zone->compact_cached_migrate_pfn[0] = zone->zone_start_pfn;
- zone->compact_cached_migrate_pfn[1] = zone->zone_start_pfn;
- zone->compact_cached_free_pfn = zone_end_pfn(zone);
+ reset_cached_positions(zone);

/*
* Mark that the PG_migrate_skip information should be cleared
@@ -1329,8 +1333,10 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
* is about to be retried after being deferred. kswapd does not do
* this reset as it'll reset the cached information when going to sleep.
*/
- if (compaction_restarting(zone, cc->order) && !current_is_kswapd())
+ if (compaction_restarting(zone, cc->order) && !current_is_kswapd()) {
__reset_isolation_suitable(zone);
+ reset_cached_positions(zone);
+ }

/*
* Setup to move all movable pages to the end of the zone. Used cached
--
2.1.4