diff options
| -rw-r--r-- | include/linux/memcontrol.h | 14 | ||||
| -rw-r--r-- | mm/memcontrol.c | 124 | ||||
| -rw-r--r-- | mm/vmscan.c | 8 |
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: |