diff options
Diffstat (limited to 'mm/vmscan.c')
| -rw-r--r-- | mm/vmscan.c | 84 |
1 files changed, 75 insertions, 9 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index db0970ba340d..d7a5b8566869 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -364,6 +364,21 @@ int prealloc_shrinker(struct shrinker *shrinker) if (!shrinker->nr_deferred) return -ENOMEM; + /* + * There is a window between prealloc_shrinker() + * and register_shrinker_prepared(). We don't want + * to clear bit of a shrinker in such the state + * in shrink_slab_memcg(), since this will impose + * restrictions on a code registering a shrinker + * (they would have to guarantee, their LRU lists + * are empty till shrinker is completely registered). + * So, we differ the situation, when 1)a shrinker + * is semi-registered (id is assigned, but it has + * not yet linked to shrinker_list) and 2)shrinker + * is not registered (id is not assigned). + */ + INIT_LIST_HEAD(&shrinker->list); + if (shrinker->flags & SHRINKER_MEMCG_AWARE) { if (prealloc_memcg_shrinker(shrinker)) goto free_deferred; @@ -543,6 +558,63 @@ static unsigned long do_shrink_slab(struct shrink_control *shrinkctl, return freed; } +#ifdef CONFIG_MEMCG_KMEM +static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid, + struct mem_cgroup *memcg, int priority) +{ + struct memcg_shrinker_map *map; + unsigned long freed = 0; + int ret, i; + + if (!memcg_kmem_enabled() || !mem_cgroup_online(memcg)) + return 0; + + if (!down_read_trylock(&shrinker_rwsem)) + return 0; + + map = rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_map, + true); + if (unlikely(!map)) + goto unlock; + + for_each_set_bit(i, map->map, shrinker_nr_max) { + struct shrink_control sc = { + .gfp_mask = gfp_mask, + .nid = nid, + .memcg = memcg, + }; + struct shrinker *shrinker; + + shrinker = idr_find(&shrinker_idr, i); + if (unlikely(!shrinker)) { + clear_bit(i, map->map); + continue; + } + + /* See comment in prealloc_shrinker() */ + if (unlikely(list_empty(&shrinker->list))) + continue; + + ret = do_shrink_slab(&sc, shrinker, priority); + freed += ret; + + if (rwsem_is_contended(&shrinker_rwsem)) { + freed = freed ? : 1; + break; + } + } +unlock: + up_read(&shrinker_rwsem); + return freed; +} +#else /* CONFIG_MEMCG_KMEM */ +static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid, + struct mem_cgroup *memcg, int priority) +{ + return 0; +} +#endif /* CONFIG_MEMCG_KMEM */ + /** * shrink_slab - shrink slab caches * @gfp_mask: allocation context @@ -572,8 +644,8 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid, struct shrinker *shrinker; unsigned long freed = 0; - if (memcg && (!memcg_kmem_enabled() || !mem_cgroup_online(memcg))) - return 0; + if (memcg && !mem_cgroup_is_root(memcg)) + return shrink_slab_memcg(gfp_mask, nid, memcg, priority); if (!down_read_trylock(&shrinker_rwsem)) goto out; @@ -585,13 +657,7 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid, .memcg = memcg, }; - /* - * If kernel memory accounting is disabled, we ignore - * SHRINKER_MEMCG_AWARE flag and call all shrinkers - * passing NULL for memcg. - */ - if (memcg_kmem_enabled() && - !!memcg != !!(shrinker->flags & SHRINKER_MEMCG_AWARE)) + if (!!memcg != !!(shrinker->flags & SHRINKER_MEMCG_AWARE)) continue; if (!(shrinker->flags & SHRINKER_NUMA_AWARE)) |