[-mm][PATCH 3/5] change function prototype of shrink_zone()

[KOSAKI Motohiro]

change function return type for following enhancement.
this patch have no behaver change.


Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>

---
 mm/vmscan.c |   47 ++++++++++++++++++++++++++++++++---------------
 1 file changed, 32 insertions(+), 15 deletions(-)

Index: b/mm/vmscan.c
===================================================================
--- a/mm/vmscan.c	2008-05-02 23:46:25.000000000 +0900
+++ b/mm/vmscan.c	2008-05-03 00:00:32.000000000 +0900
@@ -51,6 +51,9 @@ struct scan_control {
 	/* Incremented by the number of inactive pages that were scanned */
 	unsigned long nr_scanned;
 
+	/* number of reclaimed pages by this scanning */
+	unsigned long nr_reclaimed;
+
 	/* This context's GFP mask */
 	gfp_t gfp_mask;
 
@@ -1177,8 +1180,8 @@ static void shrink_active_list(unsigned 
 /*
  * This is a basic per-zone page freer.  Used by both kswapd and direct reclaim.
  */
-static unsigned long shrink_zone(int priority, struct zone *zone,
-				struct scan_control *sc)
+static int shrink_zone(int priority, struct zone *zone,
+		       struct scan_control *sc)
 {
 	unsigned long nr_active;
 	unsigned long nr_inactive;
@@ -1236,8 +1239,9 @@ static unsigned long shrink_zone(int pri
 		}
 	}
 
+	sc->nr_reclaimed += nr_reclaimed;
 	throttle_vm_writeout(sc->gfp_mask);
-	return nr_reclaimed;
+	return 0;
 }
 
 /*
@@ -1251,18 +1255,23 @@ static unsigned long shrink_zone(int pri
  * b) The zones may be over pages_high but they must go *over* pages_high to
  *    satisfy the `incremental min' zone defense algorithm.
  *
- * Returns the number of reclaimed pages.
+ * @priority: reclaim priority
+ * @zonelist: list of shrinking zones
+ * @sc: scan control context
+ * @ret_reclaimed: the number of reclaimed pages.
+ *
+ * Returns zonzero if error happend.
  *
  * If a zone is deemed to be full of pinned pages then just give it a light
  * scan then give up on it.
  */
-static unsigned long shrink_zones(int priority, struct zonelist *zonelist,
-					struct scan_control *sc)
+static int shrink_zones(int priority, struct zonelist *zonelist,
+			struct scan_control *sc)
 {
 	enum zone_type high_zoneidx = gfp_zone(sc->gfp_mask);
-	unsigned long nr_reclaimed = 0;
 	struct zoneref *z;
 	struct zone *zone;
+	int ret = 0;
 
 	sc->all_unreclaimable = 1;
 	for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
@@ -1291,10 +1300,13 @@ static unsigned long shrink_zones(int pr
 							priority);
 		}
 
-		nr_reclaimed += shrink_zone(priority, zone, sc);
+		ret = shrink_zone(priority, zone, sc);
+		if (ret)
+			goto out;
 	}
 
-	return nr_reclaimed;
+out:
+	return ret;
 }
  
 /*
@@ -1319,12 +1331,12 @@ static unsigned long do_try_to_free_page
 	int priority;
 	int ret = 0;
 	unsigned long total_scanned = 0;
-	unsigned long nr_reclaimed = 0;
 	struct reclaim_state *reclaim_state = current->reclaim_state;
 	unsigned long lru_pages = 0;
 	struct zoneref *z;
 	struct zone *zone;
 	enum zone_type high_zoneidx = gfp_zone(sc->gfp_mask);
+	int err;
 
 	if (scan_global_lru(sc))
 		count_vm_event(ALLOCSTALL);
@@ -1346,7 +1358,12 @@ static unsigned long do_try_to_free_page
 		sc->nr_scanned = 0;
 		if (!priority)
 			disable_swap_token();
-		nr_reclaimed += shrink_zones(priority, zonelist, sc);
+		err = shrink_zones(priority, zonelist, sc);
+		if (err == -EAGAIN) {
+			ret = 1;
+			goto out;
+		}
+
 		/*
 		 * Don't shrink slabs when reclaiming memory from
 		 * over limit cgroups
@@ -1354,13 +1371,13 @@ static unsigned long do_try_to_free_page
 		if (scan_global_lru(sc)) {
 			shrink_slab(sc->nr_scanned, sc->gfp_mask, lru_pages);
 			if (reclaim_state) {
-				nr_reclaimed += reclaim_state->reclaimed_slab;
+				sc->nr_reclaimed += reclaim_state->reclaimed_slab;
 				reclaim_state->reclaimed_slab = 0;
 			}
 		}
 		total_scanned += sc->nr_scanned;
-		if (nr_reclaimed >= sc->swap_cluster_max) {
-			ret = nr_reclaimed;
+		if (sc->nr_reclaimed >= sc->swap_cluster_max) {
+			ret = sc->nr_reclaimed;
 			goto out;
 		}
 
@@ -1383,7 +1400,7 @@ static unsigned long do_try_to_free_page
 	}
 	/* top priority shrink_caches still had more to do? don't OOM, then */
 	if (!sc->all_unreclaimable && scan_global_lru(sc))
-		ret = nr_reclaimed;
+		ret = sc->nr_reclaimed;
 out:
 	/*
 	 * Now that we've scanned all the zones at this priority level, note


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