memcg: export memory cgroup's swappiness with mem_cgroup_swappiness()

Each memory cgroup has a 'swappiness' value which can be accessed by
get_swappiness(memcg).  The major user is try_to_free_mem_cgroup_pages()
and swappiness is passed by argument.  It's propagated by scan_control.

get_swappiness() is a static function but some planned updates will need
to get swappiness from files other than memcontrol.c This patch exports
get_swappiness() as mem_cgroup_swappiness().  With this, we can remove the
argument of swapiness from try_to_free...  and drop swappiness from
scan_control.  only memcg uses it.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Ying Han <yinghan@google.com>
Cc: Shaohua Li <shaohua.li@intel.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/swap.h b/include/linux/swap.h
index a273468..44558b6 100644 (file)
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -252,11 +252,9 @@ static inline void lru_cache_add_file(struct page *page)
 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
                                        gfp_t gfp_mask, nodemask_t *mask);
 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
-                                                 gfp_t gfp_mask, bool noswap,
-                                                 unsigned int swappiness);
+                                                 gfp_t gfp_mask, bool noswap);
 extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
                                                gfp_t gfp_mask, bool noswap,
-                                               unsigned int swappiness,
                                                struct zone *zone,
                                                unsigned long *nr_scanned);
 extern int __isolate_lru_page(struct page *page, int mode, int file);
@@ -299,7 +297,14 @@ static inline void scan_unevictable_unregister_node(struct node *node)
 
 extern int kswapd_run(int nid);
 extern void kswapd_stop(int nid);
-
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR
+extern int mem_cgroup_swappiness(struct mem_cgroup *mem);
+#else
+static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
+{
+       return vm_swappiness;
+}
+#endif
 #ifdef CONFIG_SWAP
 /* linux/mm/page_io.c */
 extern int swap_readpage(struct page *);

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e013b8e..506d116 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -249,7 +249,7 @@ struct mem_cgroup {
        atomic_t        oom_lock;
        atomic_t        refcnt;
 
-       unsigned int    swappiness;
+       int     swappiness;
        /* OOM-Killer disable */
        int             oom_kill_disable;
 
@@ -1329,7 +1329,7 @@ static unsigned long mem_cgroup_margin(struct mem_cgroup *mem)
        return margin >> PAGE_SHIFT;
 }
 
-static unsigned int get_swappiness(struct mem_cgroup *memcg)
+int mem_cgroup_swappiness(struct mem_cgroup *memcg)
 {
        struct cgroup *cgrp = memcg->css.cgroup;
 
@@ -1776,12 +1776,11 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
                /* we use swappiness of local cgroup */
                if (check_soft) {
                        ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
-                               noswap, get_swappiness(victim), zone,
-                               &nr_scanned);
+                               noswap, zone, &nr_scanned);
                        *total_scanned += nr_scanned;
                } else
                        ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
-                                               noswap, get_swappiness(victim));
+                                               noswap);
                css_put(&victim->css);
                /*
                 * At shrinking usage, we can't check we should stop here or
@@ -3826,7 +3825,7 @@ try_to_free:
                        goto out;
                }
                progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
-                                               false, get_swappiness(mem));
+                                               false);
                if (!progress) {
                        nr_retries--;
                        /* maybe some writeback is necessary */
@@ -4288,7 +4287,7 @@ static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
 {
        struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
 
-       return get_swappiness(memcg);
+       return mem_cgroup_swappiness(memcg);
 }
 
 static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
@@ -4997,7 +4996,7 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
        INIT_LIST_HEAD(&mem->oom_notify);
 
        if (parent)
-               mem->swappiness = get_swappiness(parent);
+               mem->swappiness = mem_cgroup_swappiness(parent);
        atomic_set(&mem->refcnt, 1);
        mem->move_charge_at_immigrate = 0;
        mutex_init(&mem->thresholds_lock);

diff --git a/mm/vmscan.c b/mm/vmscan.c
index febbc04..0563749 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -95,8 +95,6 @@ struct scan_control {
        /* Can pages be swapped as part of reclaim? */
        int may_swap;
 
-       int swappiness;
-
        int order;
 
        /*
@@ -1770,6 +1768,13 @@ static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan,
        return shrink_inactive_list(nr_to_scan, zone, sc, priority, file);
 }
 
+static int vmscan_swappiness(struct scan_control *sc)
+{
+       if (scanning_global_lru(sc))
+               return vm_swappiness;
+       return mem_cgroup_swappiness(sc->mem_cgroup);
+}
+
 /*
  * Determine how aggressively the anon and file LRU lists should be
  * scanned.  The relative value of each set of LRU lists is determined
@@ -1830,8 +1835,8 @@ static void get_scan_count(struct zone *zone, struct scan_control *sc,
         * With swappiness at 100, anonymous and file have the same priority.
         * This scanning priority is essentially the inverse of IO cost.
         */
-       anon_prio = sc->swappiness;
-       file_prio = 200 - sc->swappiness;
+       anon_prio = vmscan_swappiness(sc);
+       file_prio = 200 - vmscan_swappiness(sc);
 
        /*
         * OK, so we have swap space and a fair amount of page cache
@@ -2220,7 +2225,6 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
                .nr_to_reclaim = SWAP_CLUSTER_MAX,
                .may_unmap = 1,
                .may_swap = 1,
-               .swappiness = vm_swappiness,
                .order = order,
                .mem_cgroup = NULL,
                .nodemask = nodemask,
@@ -2244,7 +2248,6 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
 
 unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
                                                gfp_t gfp_mask, bool noswap,
-                                               unsigned int swappiness,
                                                struct zone *zone,
                                                unsigned long *nr_scanned)
 {
@@ -2254,7 +2257,6 @@ unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
                .may_writepage = !laptop_mode,
                .may_unmap = 1,
                .may_swap = !noswap,
-               .swappiness = swappiness,
                .order = 0,
                .mem_cgroup = mem,
        };
@@ -2283,8 +2285,7 @@ unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
 
 unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
                                           gfp_t gfp_mask,
-                                          bool noswap,
-                                          unsigned int swappiness)
+                                          bool noswap)
 {
        struct zonelist *zonelist;
        unsigned long nr_reclaimed;
@@ -2294,7 +2295,6 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
                .may_unmap = 1,
                .may_swap = !noswap,
                .nr_to_reclaim = SWAP_CLUSTER_MAX,
-               .swappiness = swappiness,
                .order = 0,
                .mem_cgroup = mem_cont,
                .nodemask = NULL, /* we don't care the placement */
@@ -2445,7 +2445,6 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
                 * we want to put equal scanning pressure on each zone.
                 */
                .nr_to_reclaim = ULONG_MAX,
-               .swappiness = vm_swappiness,
                .order = order,
                .mem_cgroup = NULL,
        };
@@ -2915,7 +2914,6 @@ unsigned long shrink_all_memory(unsigned long nr_to_reclaim)
                .may_writepage = 1,
                .nr_to_reclaim = nr_to_reclaim,
                .hibernation_mode = 1,
-               .swappiness = vm_swappiness,
                .order = 0,
        };
        struct shrink_control shrink = {
@@ -3102,7 +3100,6 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
                .nr_to_reclaim = max_t(unsigned long, nr_pages,
                                       SWAP_CLUSTER_MAX),
                .gfp_mask = gfp_mask,
-               .swappiness = vm_swappiness,
                .order = order,
        };
        struct shrink_control shrink = {