mm: shrink_all_memory(): use sc.nr_reclaimed

Commit a79311c14eae4bb946a97af25f3e1b17d625985d "vmscan: bail out of
direct reclaim after swap_cluster_max pages" moved the nr_reclaimed
counter into the scan control to accumulate the number of all reclaimed
pages in a reclaim invocation.

shrink_all_memory() can use the same mechanism. it increase code
consistency and redability.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: MinChan Kim <minchan.kim@gmail.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 301f057fd115b6df67a43290e5892210c99d8269..b15dcbb9e1743c630167531bf54b95829a223d6b 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2050,16 +2050,15 @@ unsigned long global_lru_pages(void)
 #ifdef CONFIG_PM
 /*
  * Helper function for shrink_all_memory().  Tries to reclaim 'nr_pages' pages
- * from LRU lists system-wide, for given pass and priority, and returns the
- * number of reclaimed pages
+ * from LRU lists system-wide, for given pass and priority.
  *
  * For pass > 3 we also try to shrink the LRU lists that contain a few pages
  */
-static unsigned long shrink_all_zones(unsigned long nr_pages, int prio,
+static void shrink_all_zones(unsigned long nr_pages, int prio,
                                      int pass, struct scan_control *sc)
 {
        struct zone *zone;
-       unsigned long ret = 0;
+       unsigned long nr_reclaimed = 0;
 
        for_each_populated_zone(zone) {
                enum lru_list l;
@@ -2082,14 +2081,16 @@ static unsigned long shrink_all_zones(unsigned long nr_pages, int prio,
 
                                zone->lru[l].nr_scan = 0;
                                nr_to_scan = min(nr_pages, lru_pages);
-                               ret += shrink_list(l, nr_to_scan, zone,
+                               nr_reclaimed += shrink_list(l, nr_to_scan, zone,
                                                                sc, prio);
-                               if (ret >= nr_pages)
-                                       return ret;
+                               if (nr_reclaimed >= nr_pages) {
+                                       sc->nr_reclaimed = nr_reclaimed;
+                                       return;
+                               }
                        }
                }
        }
-       return ret;
+       sc->nr_reclaimed = nr_reclaimed;
 }
 
 /*
@@ -2103,7 +2104,6 @@ static unsigned long shrink_all_zones(unsigned long nr_pages, int prio,
 unsigned long shrink_all_memory(unsigned long nr_pages)
 {
        unsigned long lru_pages, nr_slab;
-       unsigned long ret = 0;
        int pass;
        struct reclaim_state reclaim_state;
        struct scan_control sc = {
@@ -2125,8 +2125,8 @@ unsigned long shrink_all_memory(unsigned long nr_pages)
                if (!reclaim_state.reclaimed_slab)
                        break;
 
-               ret += reclaim_state.reclaimed_slab;
-               if (ret >= nr_pages)
+               sc.nr_reclaimed += reclaim_state.reclaimed_slab;
+               if (sc.nr_reclaimed >= nr_pages)
                        goto out;
 
                nr_slab -= reclaim_state.reclaimed_slab;
@@ -2148,18 +2148,18 @@ unsigned long shrink_all_memory(unsigned long nr_pages)
                        sc.may_unmap = 1;
 
                for (prio = DEF_PRIORITY; prio >= 0; prio--) {
-                       unsigned long nr_to_scan = nr_pages - ret;
+                       unsigned long nr_to_scan = nr_pages - sc.nr_reclaimed;
 
                        sc.nr_scanned = 0;
-                       ret += shrink_all_zones(nr_to_scan, prio, pass, &sc);
-                       if (ret >= nr_pages)
+                       shrink_all_zones(nr_to_scan, prio, pass, &sc);
+                       if (sc.nr_reclaimed >= nr_pages)
                                goto out;
 
                        reclaim_state.reclaimed_slab = 0;
                        shrink_slab(sc.nr_scanned, sc.gfp_mask,
                                        global_lru_pages());
-                       ret += reclaim_state.reclaimed_slab;
-                       if (ret >= nr_pages)
+                       sc.nr_reclaimed += reclaim_state.reclaimed_slab;
+                       if (sc.nr_reclaimed >= nr_pages)
                                goto out;
 
                        if (sc.nr_scanned && prio < DEF_PRIORITY - 2)
@@ -2168,21 +2168,23 @@ unsigned long shrink_all_memory(unsigned long nr_pages)
        }
 
        /*
-        * If ret = 0, we could not shrink LRUs, but there may be something
-        * in slab caches
+        * If sc.nr_reclaimed = 0, we could not shrink LRUs, but there may be
+        * something in slab caches
         */
-       if (!ret) {
+       if (!sc.nr_reclaimed) {
                do {
                        reclaim_state.reclaimed_slab = 0;
                        shrink_slab(nr_pages, sc.gfp_mask, global_lru_pages());
-                       ret += reclaim_state.reclaimed_slab;
-               } while (ret < nr_pages && reclaim_state.reclaimed_slab > 0);
+                       sc.nr_reclaimed += reclaim_state.reclaimed_slab;
+               } while (sc.nr_reclaimed < nr_pages &&
+                               reclaim_state.reclaimed_slab > 0);
        }
 
+
 out:
        current->reclaim_state = NULL;
 
-       return ret;
+       return sc.nr_reclaimed;
 }
 #endif