rk: revert 20f3d0b+v3.0.66 to v3.0

[firefly-linux-kernel-4.4.55.git] / mm / vmscan.c

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 4f49535d4cd31f998fd58f456eb7ff16ccbf82f9..d036e59d302b092bc4186dbb753066416e35c9f6 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2310,7 +2310,8 @@ static bool pgdat_balanced(pg_data_t *pgdat, unsigned long balanced_pages,
        for (i = 0; i <= classzone_idx; i++)
                present_pages += pgdat->node_zones[i].present_pages;
 
-       return balanced_pages > (present_pages >> 2);
+       /* A special case here: if zone has no page, we think it's balanced */
+       return balanced_pages >= (present_pages >> 2);
 }
 
 /* is kswapd sleeping prematurely? */
@@ -2326,7 +2327,7 @@ static bool sleeping_prematurely(pg_data_t *pgdat, int order, long remaining,
                return true;
 
        /* Check the watermark levels */
-       for (i = 0; i < pgdat->nr_zones; i++) {
+       for (i = 0; i <= classzone_idx; i++) {
                struct zone *zone = pgdat->node_zones + i;
 
                if (!populated_zone(zone))
@@ -2344,7 +2345,7 @@ static bool sleeping_prematurely(pg_data_t *pgdat, int order, long remaining,
                }
 
                if (!zone_watermark_ok_safe(zone, order, high_wmark_pages(zone),
-                                                       classzone_idx, 0))
+                                                       i, 0))
                        all_zones_ok = false;
                else
                        balanced += zone->present_pages;
@@ -2451,7 +2452,6 @@ loop_again:
                        if (!zone_watermark_ok_safe(zone, order,
                                        high_wmark_pages(zone), 0, 0)) {
                                end_zone = i;
-                               *classzone_idx = i;
                                break;
                        }
                }
@@ -2510,18 +2510,18 @@ loop_again:
                                KSWAPD_ZONE_BALANCE_GAP_RATIO);
                        if (!zone_watermark_ok_safe(zone, order,
                                        high_wmark_pages(zone) + balance_gap,
-                                       end_zone, 0))
+                                       end_zone, 0)) {
                                shrink_zone(priority, zone, &sc);
-                       reclaim_state->reclaimed_slab = 0;
-                       nr_slab = shrink_slab(&shrink, sc.nr_scanned, lru_pages);
-                       sc.nr_reclaimed += reclaim_state->reclaimed_slab;
-                       total_scanned += sc.nr_scanned;
 
-                       if (zone->all_unreclaimable)
-                               continue;
-                       if (nr_slab == 0 &&
-                           !zone_reclaimable(zone))
-                               zone->all_unreclaimable = 1;
+                               reclaim_state->reclaimed_slab = 0;
+                               nr_slab = shrink_slab(&shrink, sc.nr_scanned, lru_pages);
+                               sc.nr_reclaimed += reclaim_state->reclaimed_slab;
+                               total_scanned += sc.nr_scanned;
+
+                               if (nr_slab == 0 && !zone_reclaimable(zone))
+                                       zone->all_unreclaimable = 1;
+                       }
+
                        /*
                         * If we've done a decent amount of scanning and
                         * the reclaim ratio is low, start doing writepage
@@ -2531,6 +2531,12 @@ loop_again:
                            total_scanned > sc.nr_reclaimed + sc.nr_reclaimed / 2)
                                sc.may_writepage = 1;
 
+                       if (zone->all_unreclaimable) {
+                               if (end_zone && end_zone == i)
+                                       end_zone--;
+                               continue;
+                       }
+
                        if (!zone_watermark_ok_safe(zone, order,
                                        high_wmark_pages(zone), end_zone, 0)) {
                                all_zones_ok = 0;
@@ -2709,8 +2715,8 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int order, int classzone_idx)
  */
 static int kswapd(void *p)
 {
-       unsigned long order;
-       int classzone_idx;
+       unsigned long order, new_order;
+       int classzone_idx, new_classzone_idx;
        pg_data_t *pgdat = (pg_data_t*)p;
        struct task_struct *tsk = current;
 
@@ -2740,17 +2746,23 @@ static int kswapd(void *p)
        tsk->flags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD;
        set_freezable();
 
-       order = 0;
-       classzone_idx = MAX_NR_ZONES - 1;
+       order = new_order = 0;
+       classzone_idx = new_classzone_idx = pgdat->nr_zones - 1;
        for ( ; ; ) {
-               unsigned long new_order;
-               int new_classzone_idx;
                int ret;
 
-               new_order = pgdat->kswapd_max_order;
-               new_classzone_idx = pgdat->classzone_idx;
-               pgdat->kswapd_max_order = 0;
-               pgdat->classzone_idx = MAX_NR_ZONES - 1;
+               /*
+                * If the last balance_pgdat was unsuccessful it's unlikely a
+                * new request of a similar or harder type will succeed soon
+                * so consider going to sleep on the basis we reclaimed at
+                */
+               if (classzone_idx >= new_classzone_idx && order == new_order) {
+                       new_order = pgdat->kswapd_max_order;
+                       new_classzone_idx = pgdat->classzone_idx;
+                       pgdat->kswapd_max_order =  0;
+                       pgdat->classzone_idx = pgdat->nr_zones - 1;
+               }
+
                if (order < new_order || classzone_idx > new_classzone_idx) {
                        /*
                         * Don't sleep if someone wants a larger 'order'
@@ -2763,7 +2775,7 @@ static int kswapd(void *p)
                        order = pgdat->kswapd_max_order;
                        classzone_idx = pgdat->classzone_idx;
                        pgdat->kswapd_max_order = 0;
-                       pgdat->classzone_idx = MAX_NR_ZONES - 1;
+                       pgdat->classzone_idx = pgdat->nr_zones - 1;
                }
 
                ret = try_to_freeze();