mm/compaction: pass pgdat to too_many_isolated() instead of zone

too_many_isolated() in mm/compaction.c looks only at node state, so it
makes more sense to change argument to pgdat instead of zone.

Link: http://lkml.kernel.org/r/20190228083329.31892-3-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Rik van Riel <riel@surriel.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/compaction.c

@@ -738,16 +738,16 @@ isolate_freepages_range(struct compact_control *cc,
 }
 
 /* Similar to reclaim, but different enough that they don't share logic */
-static bool too_many_isolated(struct zone *zone)
+static bool too_many_isolated(pg_data_t *pgdat)
 {
 	unsigned long active, inactive, isolated;
 
-	inactive = node_page_state(zone->zone_pgdat, NR_INACTIVE_FILE) +
-			node_page_state(zone->zone_pgdat, NR_INACTIVE_ANON);
-	active = node_page_state(zone->zone_pgdat, NR_ACTIVE_FILE) +
-			node_page_state(zone->zone_pgdat, NR_ACTIVE_ANON);
-	isolated = node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE) +
-			node_page_state(zone->zone_pgdat, NR_ISOLATED_ANON);
+	inactive = node_page_state(pgdat, NR_INACTIVE_FILE) +
+			node_page_state(pgdat, NR_INACTIVE_ANON);
+	active = node_page_state(pgdat, NR_ACTIVE_FILE) +
+			node_page_state(pgdat, NR_ACTIVE_ANON);
+	isolated = node_page_state(pgdat, NR_ISOLATED_FILE) +
+			node_page_state(pgdat, NR_ISOLATED_ANON);
 
 	return isolated > (inactive + active) / 2;
 }
@@ -774,8 +774,7 @@ static unsigned long
 isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 			unsigned long end_pfn, isolate_mode_t isolate_mode)
 {
-	struct zone *zone = cc->zone;
-	pg_data_t *pgdat = zone->zone_pgdat;
+	pg_data_t *pgdat = cc->zone->zone_pgdat;
 	unsigned long nr_scanned = 0, nr_isolated = 0;
 	struct lruvec *lruvec;
 	unsigned long flags = 0;
@@ -791,7 +790,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 	 * list by either parallel reclaimers or compaction. If there are,
 	 * delay for some time until fewer pages are isolated
 	 */
-	while (unlikely(too_many_isolated(zone))) {
+	while (unlikely(too_many_isolated(pgdat))) {
 		/* async migration should just abort */
 		if (cc->mode == MIGRATE_ASYNC)
 			return 0;