On 02/04/2014 06:45 PM, Michal Hocko wrote:
> On Sun 02-02-14 20:33:47, Vladimir Davydov wrote:
>> The cgroup name is not informative at all in case the cgroup hierarchy
>> is not flat. Besides, we can always find the memcg a particular cache
>> belongs to by its kmemcg id, which is now exported via "memory.kmem.id"
>> cgroup fs file for each memcg.
>>
>> So let's remove the cgroup name part from kmem caches names - it will
>> greatly simplify the call paths and make the code look clearer.
>>
>> Signed-off-by: Vladimir Davydov <vdavy...@parallels.com>
> I guess this one doesn't make much sense withou 1/8, right?

Actually, the rest of the patchset does not depend on the logic of the
first two - they only have a couple of hunks overlapped. However, there
is v2 already.

Thanks.

>
>> ---
>>  mm/memcontrol.c  |   63 
>> +++++++++++++-----------------------------------------
>>  mm/slab_common.c |    6 +++++-
>>  2 files changed, 20 insertions(+), 49 deletions(-)
>>
>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
>> index 91d242707404..3351c5b5486d 100644
>> --- a/mm/memcontrol.c
>> +++ b/mm/memcontrol.c
>> @@ -3405,44 +3405,6 @@ void mem_cgroup_destroy_cache(struct kmem_cache 
>> *cachep)
>>      schedule_work(&cachep->memcg_params->destroy);
>>  }
>>  
>> -static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg,
>> -                                              struct kmem_cache *s)
>> -{
>> -    struct kmem_cache *new = NULL;
>> -    static char *tmp_name = NULL;
>> -    static DEFINE_MUTEX(mutex);     /* protects tmp_name */
>> -
>> -    BUG_ON(!memcg_can_account_kmem(memcg));
>> -
>> -    mutex_lock(&mutex);
>> -    /*
>> -     * kmem_cache_create_memcg duplicates the given name and
>> -     * cgroup_name for this name requires RCU context.
>> -     * This static temporary buffer is used to prevent from
>> -     * pointless shortliving allocation.
>> -     */
>> -    if (!tmp_name) {
>> -            tmp_name = kmalloc(PATH_MAX, GFP_KERNEL);
>> -            if (!tmp_name)
>> -                    goto out;
>> -    }
>> -
>> -    rcu_read_lock();
>> -    snprintf(tmp_name, PATH_MAX, "%s(%d:%s)", s->name,
>> -                     memcg_cache_id(memcg), cgroup_name(memcg->css.cgroup));
>> -    rcu_read_unlock();
>> -
>> -    new = kmem_cache_create_memcg(memcg, tmp_name, s->object_size, s->align,
>> -                                  (s->flags & ~SLAB_PANIC), s->ctor, s);
>> -    if (new)
>> -            new->allocflags |= __GFP_KMEMCG;
>> -    else
>> -            new = s;
>> -out:
>> -    mutex_unlock(&mutex);
>> -    return new;
>> -}
>> -
>>  void kmem_cache_destroy_memcg_children(struct kmem_cache *s)
>>  {
>>      struct kmem_cache *c;
>> @@ -3489,12 +3451,6 @@ void kmem_cache_destroy_memcg_children(struct 
>> kmem_cache *s)
>>      mutex_unlock(&activate_kmem_mutex);
>>  }
>>  
>> -struct create_work {
>> -    struct mem_cgroup *memcg;
>> -    struct kmem_cache *cachep;
>> -    struct work_struct work;
>> -};
>> -
>>  static void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg)
>>  {
>>      struct kmem_cache *cachep;
>> @@ -3512,13 +3468,24 @@ static void mem_cgroup_destroy_all_caches(struct 
>> mem_cgroup *memcg)
>>      mutex_unlock(&memcg->slab_caches_mutex);
>>  }
>>  
>> +struct create_work {
>> +    struct mem_cgroup *memcg;
>> +    struct kmem_cache *cachep;
>> +    struct work_struct work;
>> +};
>> +
>>  static void memcg_create_cache_work_func(struct work_struct *w)
>>  {
>> -    struct create_work *cw;
>> +    struct create_work *cw = container_of(w, struct create_work, work);
>> +    struct mem_cgroup *memcg = cw->memcg;
>> +    struct kmem_cache *s = cw->cachep;
>> +    struct kmem_cache *new;
>>  
>> -    cw = container_of(w, struct create_work, work);
>> -    memcg_create_kmem_cache(cw->memcg, cw->cachep);
>> -    css_put(&cw->memcg->css);
>> +    new = kmem_cache_create_memcg(memcg, s->name, s->object_size, s->align,
>> +                                  (s->flags & ~SLAB_PANIC), s->ctor, s);
>> +    if (new)
>> +            new->allocflags |= __GFP_KMEMCG;
>> +    css_put(&memcg->css);
>>      kfree(cw);
>>  }
>>  
>> diff --git a/mm/slab_common.c b/mm/slab_common.c
>> index 1ec3c619ba04..152d9b118b7a 100644
>> --- a/mm/slab_common.c
>> +++ b/mm/slab_common.c
>> @@ -213,7 +213,11 @@ kmem_cache_create_memcg(struct mem_cgroup *memcg, const 
>> char *name, size_t size,
>>      s->align = calculate_alignment(flags, align, size);
>>      s->ctor = ctor;
>>  
>> -    s->name = kstrdup(name, GFP_KERNEL);
>> +    if (!memcg)
>> +            s->name = kstrdup(name, GFP_KERNEL);
>> +    else
>> +            s->name = kasprintf(GFP_KERNEL, "%s:%d",
>> +                                name, memcg_cache_id(memcg));
>>      if (!s->name)
>>              goto out_free_cache;
>>  
>> -- 
>> 1.7.10.4
>>

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