diff options
| -rw-r--r-- | include/linux/memcontrol.h | 6 | ||||
| -rw-r--r-- | mm/slab.c | 1 | ||||
| -rw-r--r-- | mm/slub.c | 21 |
3 files changed, 24 insertions, 4 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index ea02ff97083..0108a56f814 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -422,6 +422,12 @@ static inline void sock_release_memcg(struct sock *sk) extern struct static_key memcg_kmem_enabled_key; extern int memcg_limited_groups_array_size; + +/* + * Helper macro to loop through all memcg-specific caches. Callers must still + * check if the cache is valid (it is either valid or NULL). + * the slab_mutex must be held when looping through those caches + */ #define for_each_memcg_cache_index(_idx) \ for ((_idx) = 0; i < memcg_limited_groups_array_size; (_idx)++) diff --git a/mm/slab.c b/mm/slab.c index 4dcbf96a77b..e7667a3584b 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -4099,6 +4099,7 @@ static int do_tune_cpucache(struct kmem_cache *cachep, int limit, if ((ret < 0) || !is_root_cache(cachep)) return ret; + VM_BUG_ON(!mutex_is_locked(&slab_mutex)); for_each_memcg_cache_index(i) { c = cache_from_memcg(cachep, i); if (c) diff --git a/mm/slub.c b/mm/slub.c index 21c94d9695e..efe2cffc29b 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -5108,12 +5108,25 @@ static ssize_t slab_attr_store(struct kobject *kobj, if (s->max_attr_size < len) s->max_attr_size = len; + /* + * This is a best effort propagation, so this function's return + * value will be determined by the parent cache only. This is + * basically because not all attributes will have a well + * defined semantics for rollbacks - most of the actions will + * have permanent effects. + * + * Returning the error value of any of the children that fail + * is not 100 % defined, in the sense that users seeing the + * error code won't be able to know anything about the state of + * the cache. + * + * Only returning the error code for the parent cache at least + * has well defined semantics. The cache being written to + * directly either failed or succeeded, in which case we loop + * through the descendants with best-effort propagation. + */ for_each_memcg_cache_index(i) { struct kmem_cache *c = cache_from_memcg(s, i); - /* - * This function's return value is determined by the - * parent cache only - */ if (c) attribute->store(c, buf, len); } |