From 02333641e2cf4ac9f23eeeb01183ed8318d346ca Mon Sep 17 00:00:00 2001
From: Vlastimil Babka <vbabka@suse.cz>
Date: Tue, 8 Sep 2015 15:02:42 -0700
Subject: [PATCH] mm, compaction: encapsulate resetting cached scanner
 positions

Reseting the cached compaction scanner positions is now open-coded in
__reset_isolation_suitable() and compact_finished().  Encapsulate the
functionality in a new function reset_cached_positions().

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>
Acked-by: 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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 mm/compaction.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index 2c1e1ff321bf..0dce7e87d771 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 */
@@ -238,6 +242,8 @@ static void __reset_isolation_suitable(struct zone *zone)
 
 		clear_pageblock_skip(page);
 	}
+
+	reset_cached_positions(zone);
 }
 
 void reset_isolation_suitable(pg_data_t *pgdat)
@@ -1160,9 +1166,7 @@ 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
-- 
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