vmscan: change shrink_slab() interfaces by passing shrink_control

Consolidate the existing parameters to shrink_slab() into a new
shrink_control struct.  This is needed later to pass the same struct to
shrinkers.

Signed-off-by: Ying Han <yinghan@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 39 insertions, 14 deletions

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 369b80e81416..341341b2b47b 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -239,7 +239,12 @@ void shake_page(struct page *p, int access)
         if (access) {
                 int nr;
                 do {
-                        nr = shrink_slab(1000, GFP_KERNEL, 1000);
+                        struct shrink_control shrink = {
+                                .gfp_mask = GFP_KERNEL,
+                                .nr_scanned = 1000,
+                        };
+
+                        nr = shrink_slab(&shrink, 1000);
                         if (page_count(p) == 1)
                                 break;
                 } while (nr > 10);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 890f54184d9a..e4e245ed1a5b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -222,11 +222,13 @@ EXPORT_SYMBOL(unregister_shrinker);
  *
  * Returns the number of slab objects which we shrunk.
  */
-unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask,
-                        unsigned long lru_pages)
+unsigned long shrink_slab(struct shrink_control *shrink,
+                          unsigned long lru_pages)
 {
         struct shrinker *shrinker;
         unsigned long ret = 0;
+        unsigned long scanned = shrink->nr_scanned;
+        gfp_t gfp_mask = shrink->gfp_mask;
 
         if (scanned == 0)
                 scanned = SWAP_CLUSTER_MAX;
@@ -2035,7 +2037,8 @@ static bool all_unreclaimable(struct zonelist *zonelist,
  *              else, the number of pages reclaimed
  */
 static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
-                                        struct scan_control *sc)
+                                        struct scan_control *sc,
+                                        struct shrink_control *shrink)
 {
         int priority;
         unsigned long total_scanned = 0;
@@ -2069,7 +2072,8 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
                                 lru_pages += zone_reclaimable_pages(zone);
                         }
 
-                        shrink_slab(sc->nr_scanned, sc->gfp_mask, lru_pages);
+                        shrink->nr_scanned = sc->nr_scanned;
+                        shrink_slab(shrink, lru_pages);
                         if (reclaim_state) {
                                 sc->nr_reclaimed += reclaim_state->reclaimed_slab;
                                 reclaim_state->reclaimed_slab = 0;
@@ -2141,12 +2145,15 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
                 .mem_cgroup = NULL,
                 .nodemask = nodemask,
         };
+        struct shrink_control shrink = {
+                .gfp_mask = sc.gfp_mask,
+        };
 
         trace_mm_vmscan_direct_reclaim_begin(order,
                                 sc.may_writepage,
                                 gfp_mask);
 
-        nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
+        nr_reclaimed = do_try_to_free_pages(zonelist, &sc, &shrink);
 
         trace_mm_vmscan_direct_reclaim_end(nr_reclaimed);
 
@@ -2206,17 +2213,20 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
                 .order = 0,
                 .mem_cgroup = mem_cont,
                 .nodemask = NULL, /* we don't care the placement */
+                .gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
+                                (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK),
+        };
+        struct shrink_control shrink = {
+                .gfp_mask = sc.gfp_mask,
         };
 
-        sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
-                        (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
         zonelist = NODE_DATA(numa_node_id())->node_zonelists;
 
         trace_mm_vmscan_memcg_reclaim_begin(0,
                                             sc.may_writepage,
                                             sc.gfp_mask);
 
-        nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
+        nr_reclaimed = do_try_to_free_pages(zonelist, &sc, &shrink);
 
         trace_mm_vmscan_memcg_reclaim_end(nr_reclaimed);
 
@@ -2344,6 +2354,9 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
                 .order = order,
                 .mem_cgroup = NULL,
         };
+        struct shrink_control shrink = {
+                .gfp_mask = sc.gfp_mask,
+        };
 loop_again:
         total_scanned = 0;
         sc.nr_reclaimed = 0;
@@ -2443,8 +2456,8 @@ loop_again:
                                         end_zone, 0))
                                 shrink_zone(priority, zone, &sc);
                         reclaim_state->reclaimed_slab = 0;
-                        nr_slab = shrink_slab(sc.nr_scanned, GFP_KERNEL,
-                                                lru_pages);
+                        shrink.nr_scanned = sc.nr_scanned;
+                        nr_slab = shrink_slab(&shrink, lru_pages);
                         sc.nr_reclaimed += reclaim_state->reclaimed_slab;
                         total_scanned += sc.nr_scanned;
 
@@ -2796,7 +2809,10 @@ unsigned long shrink_all_memory(unsigned long nr_to_reclaim)
                 .swappiness = vm_swappiness,
                 .order = 0,
         };
-        struct zonelist * zonelist = node_zonelist(numa_node_id(), sc.gfp_mask);
+        struct shrink_control shrink = {
+                .gfp_mask = sc.gfp_mask,
+        };
+        struct zonelist *zonelist = node_zonelist(numa_node_id(), sc.gfp_mask);
         struct task_struct *p = current;
         unsigned long nr_reclaimed;
 
@@ -2805,7 +2821,7 @@ unsigned long shrink_all_memory(unsigned long nr_to_reclaim)
         reclaim_state.reclaimed_slab = 0;
         p->reclaim_state = &reclaim_state;
 
-        nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
+        nr_reclaimed = do_try_to_free_pages(zonelist, &sc, &shrink);
 
         p->reclaim_state = NULL;
         lockdep_clear_current_reclaim_state();
@@ -2980,6 +2996,9 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
                 .swappiness = vm_swappiness,
                 .order = order,
         };
+        struct shrink_control shrink = {
+                .gfp_mask = sc.gfp_mask,
+        };
         unsigned long nr_slab_pages0, nr_slab_pages1;
 
         cond_resched();
@@ -3006,6 +3025,7 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
         }
 
         nr_slab_pages0 = zone_page_state(zone, NR_SLAB_RECLAIMABLE);
+        shrink.nr_scanned = sc.nr_scanned;
         if (nr_slab_pages0 > zone->min_slab_pages) {
                 /*
                  * shrink_slab() does not currently allow us to determine how
@@ -3021,7 +3041,7 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
                         unsigned long lru_pages = zone_reclaimable_pages(zone);
 
                         /* No reclaimable slab or very low memory pressure */
-                        if (!shrink_slab(sc.nr_scanned, gfp_mask, lru_pages))
+                        if (!shrink_slab(&shrink, lru_pages))
                                 break;
 
                         /* Freed enough memory */