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-rw-r--r--include/linux/memcontrol.h14
-rw-r--r--mm/memcontrol.c124
-rw-r--r--mm/vmscan.c8
3 files changed, 145 insertions, 1 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index f3c026df7443..2cccbb9e1b3e 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -112,6 +112,15 @@ struct lruvec_stat {
};
/*
+ * Bitmap of shrinker::id corresponding to memcg-aware shrinkers,
+ * which have elements charged to this memcg.
+ */
+struct memcg_shrinker_map {
+ struct rcu_head rcu;
+ unsigned long map[0];
+};
+
+/*
* per-zone information in memory controller.
*/
struct mem_cgroup_per_node {
@@ -124,6 +133,9 @@ struct mem_cgroup_per_node {
struct mem_cgroup_reclaim_iter iter[DEF_PRIORITY + 1];
+#ifdef CONFIG_MEMCG_KMEM
+ struct memcg_shrinker_map __rcu *shrinker_map;
+#endif
struct rb_node tree_node; /* RB tree node */
unsigned long usage_in_excess;/* Set to the value by which */
/* the soft limit is exceeded*/
@@ -1262,6 +1274,8 @@ static inline int memcg_cache_id(struct mem_cgroup *memcg)
return memcg ? memcg->kmemcg_id : -1;
}
+extern int memcg_expand_shrinker_maps(int new_id);
+
#else
#define for_each_memcg_cache_index(_idx) \
for (; NULL; )
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 313355dddf66..827c9e87ca08 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -320,6 +320,119 @@ EXPORT_SYMBOL(memcg_kmem_enabled_key);
struct workqueue_struct *memcg_kmem_cache_wq;
+static int memcg_shrinker_map_size;
+static DEFINE_MUTEX(memcg_shrinker_map_mutex);
+
+static void memcg_free_shrinker_map_rcu(struct rcu_head *head)
+{
+ kvfree(container_of(head, struct memcg_shrinker_map, rcu));
+}
+
+static int memcg_expand_one_shrinker_map(struct mem_cgroup *memcg,
+ int size, int old_size)
+{
+ struct memcg_shrinker_map *new, *old;
+ int nid;
+
+ lockdep_assert_held(&memcg_shrinker_map_mutex);
+
+ for_each_node(nid) {
+ old = rcu_dereference_protected(
+ mem_cgroup_nodeinfo(memcg, nid)->shrinker_map, true);
+ /* Not yet online memcg */
+ if (!old)
+ return 0;
+
+ new = kvmalloc(sizeof(*new) + size, GFP_KERNEL);
+ if (!new)
+ return -ENOMEM;
+
+ /* Set all old bits, clear all new bits */
+ memset(new->map, (int)0xff, old_size);
+ memset((void *)new->map + old_size, 0, size - old_size);
+
+ rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_map, new);
+ call_rcu(&old->rcu, memcg_free_shrinker_map_rcu);
+ }
+
+ return 0;
+}
+
+static void memcg_free_shrinker_maps(struct mem_cgroup *memcg)
+{
+ struct mem_cgroup_per_node *pn;
+ struct memcg_shrinker_map *map;
+ int nid;
+
+ if (mem_cgroup_is_root(memcg))
+ return;
+
+ for_each_node(nid) {
+ pn = mem_cgroup_nodeinfo(memcg, nid);
+ map = rcu_dereference_protected(pn->shrinker_map, true);
+ if (map)
+ kvfree(map);
+ rcu_assign_pointer(pn->shrinker_map, NULL);
+ }
+}
+
+static int memcg_alloc_shrinker_maps(struct mem_cgroup *memcg)
+{
+ struct memcg_shrinker_map *map;
+ int nid, size, ret = 0;
+
+ if (mem_cgroup_is_root(memcg))
+ return 0;
+
+ mutex_lock(&memcg_shrinker_map_mutex);
+ size = memcg_shrinker_map_size;
+ for_each_node(nid) {
+ map = kvzalloc(sizeof(*map) + size, GFP_KERNEL);
+ if (!map) {
+ memcg_free_shrinker_maps(memcg);
+ ret = -ENOMEM;
+ break;
+ }
+ rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_map, map);
+ }
+ mutex_unlock(&memcg_shrinker_map_mutex);
+
+ return ret;
+}
+
+int memcg_expand_shrinker_maps(int new_id)
+{
+ int size, old_size, ret = 0;
+ struct mem_cgroup *memcg;
+
+ size = DIV_ROUND_UP(new_id + 1, BITS_PER_LONG) * sizeof(unsigned long);
+ old_size = memcg_shrinker_map_size;
+ if (size <= old_size)
+ return 0;
+
+ mutex_lock(&memcg_shrinker_map_mutex);
+ if (!root_mem_cgroup)
+ goto unlock;
+
+ for_each_mem_cgroup(memcg) {
+ if (mem_cgroup_is_root(memcg))
+ continue;
+ ret = memcg_expand_one_shrinker_map(memcg, size, old_size);
+ if (ret)
+ goto unlock;
+ }
+unlock:
+ if (!ret)
+ memcg_shrinker_map_size = size;
+ mutex_unlock(&memcg_shrinker_map_mutex);
+ return ret;
+}
+#else /* CONFIG_MEMCG_KMEM */
+static int memcg_alloc_shrinker_maps(struct mem_cgroup *memcg)
+{
+ return 0;
+}
+static void memcg_free_shrinker_maps(struct mem_cgroup *memcg) { }
#endif /* CONFIG_MEMCG_KMEM */
/**
@@ -4356,6 +4469,16 @@ static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+ /*
+ * A memcg must be visible for memcg_expand_shrinker_maps()
+ * by the time the maps are allocated. So, we allocate maps
+ * here, when for_each_mem_cgroup() can't skip it.
+ */
+ if (memcg_alloc_shrinker_maps(memcg)) {
+ mem_cgroup_id_remove(memcg);
+ return -ENOMEM;
+ }
+
/* Online state pins memcg ID, memcg ID pins CSS */
atomic_set(&memcg->id.ref, 1);
css_get(css);
@@ -4408,6 +4531,7 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
vmpressure_cleanup(&memcg->vmpressure);
cancel_work_sync(&memcg->high_work);
mem_cgroup_remove_from_trees(memcg);
+ memcg_free_shrinker_maps(memcg);
memcg_free_kmem(memcg);
mem_cgroup_free(memcg);
}
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 5cb4f779ea4a..db0970ba340d 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -183,8 +183,14 @@ static int prealloc_memcg_shrinker(struct shrinker *shrinker)
if (id < 0)
goto unlock;
- if (id >= shrinker_nr_max)
+ if (id >= shrinker_nr_max) {
+ if (memcg_expand_shrinker_maps(id)) {
+ idr_remove(&shrinker_idr, id);
+ goto unlock;
+ }
+
shrinker_nr_max = id + 1;
+ }
shrinker->id = id;
ret = 0;
unlock: