Re: [PATCH 2/6] memcg, slab: kmem_cache_create_memcg(): free memcg params on error

[Vladimir Davydov <vdavydov-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>]

On 12/18/2013 09:06 PM, Michal Hocko wrote:
> On Wed 18-12-13 17:16:53, Vladimir Davydov wrote:
>> Plus, rename memcg_register_cache() to memcg_init_cache_params(),
>> because it actually does not register the cache anywhere, but simply
>> initialize kmem_cache::memcg_params.
> I've almost missed this is a memory leak fix.

Yeah, the comment is poor, sorry about that. Will fix it.

> I do not mind renaming and the name but wouldn't
> memcg_alloc_cache_params suit better?

As you wish. I don't have a strong preference for memcg_init_cache_params.

Thanks.

>
>> Signed-off-by: Vladimir Davydov <vdavydov-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
>> Cc: Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>
>> Cc: Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
>> Cc: Glauber Costa <glommer-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>> Cc: Christoph Lameter <cl-vYTEC60ixJUAvxtiuMwx3w@public.gmane.org>
>> Cc: Pekka Enberg <penberg-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
>> Cc: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
>> ---
>>  include/linux/memcontrol.h |   13 +++++++++----
>>  mm/memcontrol.c            |    9 +++++++--
>>  mm/slab_common.c           |    3 ++-
>>  3 files changed, 18 insertions(+), 7 deletions(-)
>>
>> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
>> index b3e7a66..b357ae3 100644
>> --- a/include/linux/memcontrol.h
>> +++ b/include/linux/memcontrol.h
>> @@ -497,8 +497,9 @@ void __memcg_kmem_commit_charge(struct page *page,
>>  void __memcg_kmem_uncharge_pages(struct page *page, int order);
>>  
>>  int memcg_cache_id(struct mem_cgroup *memcg);
>> -int memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s,
>> -			 struct kmem_cache *root_cache);
>> +int memcg_init_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s,
>> +			    struct kmem_cache *root_cache);
>> +void memcg_free_cache_params(struct kmem_cache *s);
>>  void memcg_release_cache(struct kmem_cache *cachep);
>>  void memcg_cache_list_add(struct mem_cgroup *memcg, struct kmem_cache *cachep);
>>  
>> @@ -641,12 +642,16 @@ static inline int memcg_cache_id(struct mem_cgroup *memcg)
>>  }
>>  
>>  static inline int
>> -memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s,
>> -		     struct kmem_cache *root_cache)
>> +memcg_init_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s,
>> +			struct kmem_cache *root_cache)
>>  {
>>  	return 0;
>>  }
>>  
>> +static inline void memcg_free_cache_params(struct kmem_cache *s);
>> +{
>> +}
>> +
>>  static inline void memcg_release_cache(struct kmem_cache *cachep)
>>  {
>>  }
>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
>> index bf5e894..e6ad6ff 100644
>> --- a/mm/memcontrol.c
>> +++ b/mm/memcontrol.c
>> @@ -3195,8 +3195,8 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
>>  	return 0;
>>  }
>>  
>> -int memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s,
>> -			 struct kmem_cache *root_cache)
>> +int memcg_init_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s,
>> +			    struct kmem_cache *root_cache)
>>  {
>>  	size_t size;
>>  
>> @@ -3224,6 +3224,11 @@ int memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s,
>>  	return 0;
>>  }
>>  
>> +void memcg_free_cache_params(struct kmem_cache *s)
>> +{
>> +	kfree(s->memcg_params);
>> +}
>> +
>>  void memcg_release_cache(struct kmem_cache *s)
>>  {
>>  	struct kmem_cache *root;
>> diff --git a/mm/slab_common.c b/mm/slab_common.c
>> index 5d6f743..62712fe 100644
>> --- a/mm/slab_common.c
>> +++ b/mm/slab_common.c
>> @@ -208,7 +208,7 @@ kmem_cache_create_memcg(struct mem_cgroup *memcg, const char *name, size_t size,
>>  		goto out_free_cache;
>>  	}
>>  
>> -	err = memcg_register_cache(memcg, s, parent_cache);
>> +	err = memcg_init_cache_params(memcg, s, parent_cache);
>>  	if (err)
>>  		goto out_free_cache;
>>  
>> @@ -238,6 +238,7 @@ out_unlock:
>>  	return s;
>>  
>>  out_free_cache:
>> +	memcg_free_cache_params(s);
>>  	kfree(s->name);
>>  	kmem_cache_free(kmem_cache, s);
>>  	goto out_unlock;
>> -- 
>> 1.7.10.4
>>