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>

diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index 98b77c8..440999c 100644 (file)
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -40,9 +40,13 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused)
 static void drop_slab(void)
 {
        int nr_objects;
+       struct shrink_control shrink = {
+               .gfp_mask = GFP_KERNEL,
+               .nr_scanned = 1000,
+       };
 
        do {
-               nr_objects = shrink_slab(1000, GFP_KERNEL, 1000);
+               nr_objects = shrink_slab(&shrink, 1000);
        } while (nr_objects > 10);
 }
 

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8e2f2cd..32cfa96 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1161,6 +1161,15 @@ static inline void sync_mm_rss(struct task_struct *task, struct mm_struct *mm)
 }
 #endif
 
+/*
+ * This struct is used to pass information from page reclaim to the shrinkers.
+ * We consolidate the values for easier extention later.
+ */
+struct shrink_control {
+       unsigned long nr_scanned;
+       gfp_t gfp_mask;
+};
+
 /*
  * A callback you can register to apply pressure to ageable caches.
  *
@@ -1630,8 +1639,8 @@ int in_gate_area_no_mm(unsigned long addr);
 
 int drop_caches_sysctl_handler(struct ctl_table *, int,
                                        void __user *, size_t *, loff_t *);
-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);
 
 #ifndef CONFIG_MMU
 #define randomize_va_space 0

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 369b80e..341341b 100644 (file)
--- 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 890f541..e4e245e 100644 (file)
--- 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 */