mm: compaction: refactor compact_node()

Commit Message

Kefeng Wang Feb. 7, 2024, 9:58 a.m. UTC

Refactor compact_node() to handle both proactive and synchronous compact
memory, which cleanups code a bit.

Signed-off-by: Kefeng Wang <[e-mail]>
---
 mm/compaction.c | 66 +++++++++++++++++--------------------------------
 1 file changed, 23 insertions(+), 43 deletions(-)

Comments

Andrew Morton Feb. 7, 2024, 11:48 p.m. UTC | #1

On Wed, 7 Feb 2024 17:58:41 +0800 Kefeng Wang <[e-mail]> wrote:

> Refactor compact_node() to handle both proactive and synchronous compact
> memory, which cleanups code a bit.

Looks good.

> + * Compact all zones within a node till each zone's fragmentation score
> + * reaches within proactive compaction thresholds (as determined by the
> + * proactiveness tunable).
> + *
> + * It is possible that the function returns before reaching score targets
> + * due to various back-off conditions, such as, contention on per-node or
> + * per-zone locks.
> + */
> +static void proactive_compact_node(pg_data_t *pgdat)
>  {
> -	pg_data_t *pgdat = NODE_DATA(nid);
> -	int zoneid;
> -	struct zone *zone;
> -	struct compact_control cc = {
> -		.order = -1,
> -		.mode = MIGRATE_SYNC,
> -		.ignore_skip_hint = true,
> -		.whole_zone = true,
> -		.gfp_mask = GFP_KERNEL,
> -	};
> -
> -
> -	for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) {
> -
> -		zone = &pgdat->node_zones[zoneid];
> -		if (!populated_zone(zone))
> -			continue;
> -
> -		cc.zone = zone;
> -
> -		compact_zone(&cc, NULL);
> -	}
> +	compact_node(pgdat, true);
>  }

I suggest that proactive_compact_node() be removed.  Move its comment
to compact_node(), add explanation of the bool argument to that comment
and open-code the call to compact_node() at proactive_compact_node()'s
sole call site.

Patch

diff --git a/mm/compaction.c b/mm/compaction.c
index e63a4ee7e029..f2d886a88ee1 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -2884,26 +2884,17 @@  enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
 	return rc;
 }
 
-/*
- * Compact all zones within a node till each zone's fragmentation score
- * reaches within proactive compaction thresholds (as determined by the
- * proactiveness tunable).
- *
- * It is possible that the function returns before reaching score targets
- * due to various back-off conditions, such as, contention on per-node or
- * per-zone locks.
- */
-static void proactive_compact_node(pg_data_t *pgdat)
+static void compact_node(pg_data_t *pgdat, bool proactive)
 {
 	int zoneid;
 	struct zone *zone;
 	struct compact_control cc = {
 		.order = -1,
-		.mode = MIGRATE_SYNC_LIGHT,
+		.mode = proactive ? MIGRATE_SYNC_LIGHT : MIGRATE_SYNC,
 		.ignore_skip_hint = true,
 		.whole_zone = true,
 		.gfp_mask = GFP_KERNEL,
-		.proactive_compaction = true,
+		.proactive_compaction = proactive,
 	};
 
 	for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) {
@@ -2915,41 +2906,30 @@  static void proactive_compact_node(pg_data_t *pgdat)
 
 		compact_zone(&cc, NULL);
 
-		count_compact_events(KCOMPACTD_MIGRATE_SCANNED,
-				     cc.total_migrate_scanned);
-		count_compact_events(KCOMPACTD_FREE_SCANNED,
-				     cc.total_free_scanned);
+		if (proactive) {
+			count_compact_events(KCOMPACTD_MIGRATE_SCANNED,
+					     cc.total_migrate_scanned);
+			count_compact_events(KCOMPACTD_FREE_SCANNED,
+					     cc.total_free_scanned);
+		}
 	}
 }
 
-/* Compact all zones within a node */
-static void compact_node(int nid)
+/*
+ * Compact all zones within a node till each zone's fragmentation score
+ * reaches within proactive compaction thresholds (as determined by the
+ * proactiveness tunable).
+ *
+ * It is possible that the function returns before reaching score targets
+ * due to various back-off conditions, such as, contention on per-node or
+ * per-zone locks.
+ */
+static void proactive_compact_node(pg_data_t *pgdat)
 {
-	pg_data_t *pgdat = NODE_DATA(nid);
-	int zoneid;
-	struct zone *zone;
-	struct compact_control cc = {
-		.order = -1,
-		.mode = MIGRATE_SYNC,
-		.ignore_skip_hint = true,
-		.whole_zone = true,
-		.gfp_mask = GFP_KERNEL,
-	};
-
-
-	for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) {
-
-		zone = &pgdat->node_zones[zoneid];
-		if (!populated_zone(zone))
-			continue;
-
-		cc.zone = zone;
-
-		compact_zone(&cc, NULL);
-	}
+	compact_node(pgdat, true);
 }
 
-/* Compact all nodes in the system */
+/* Compact all zones of all nodes in the system */
 static void compact_nodes(void)
 {
 	int nid;
@@ -2958,7 +2938,7 @@  static void compact_nodes(void)
 	lru_add_drain_all();
 
 	for_each_online_node(nid)
-		compact_node(nid);
+		compact_node(NODE_DATA(nid), false);
 }
 
 static int compaction_proactiveness_sysctl_handler(struct ctl_table *table, int write,
@@ -3020,7 +3000,7 @@  static ssize_t compact_store(struct device *dev,
 		/* Flush pending updates to the LRU lists */
 		lru_add_drain_all();
 
-		compact_node(nid);
+		compact_node(NODE_DATA(nid), false);
 	}
 
 	return count;