Re: [PATCH] mm/memcg: wrap mem_cgroup_from_css function

[Wanpeng Li <liwanp@linux.vnet.ibm.com>]

On Thu, Jul 19, 2012 at 12:14:20PM +0300, Kirill A. Shutemov wrote:
>On Wed, Jul 18, 2012 at 11:05:30AM +0800, Wanpeng Li wrote:
>> wrap mem_cgroup_from_css function to clarify get mem cgroup
>> from cgroup_subsys_state.
>> 
>> Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
>> Cc: Michal Hocko <mhocko@suse.cz>
>> Cc: Johannes Weiner <hannes@cmpxchg.org>
>> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: Gavin Shan <shangw@linux.vnet.ibm.com>
>> Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
>> Cc: linux-kernel@vger.kernel.org
>> ---
>>  mm/memcontrol.c |   14 ++++++++++----
>>  1 files changed, 10 insertions(+), 4 deletions(-)
>> 
>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
>> index 58a08fc..20f6a15 100644
>> --- a/mm/memcontrol.c
>> +++ b/mm/memcontrol.c
>> @@ -396,6 +396,12 @@ static void mem_cgroup_put(struct mem_cgroup *memcg);
>>  #include <net/sock.h>
>>  #include <net/ip.h>
>>  
>> +static inline
>> +struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *s)
>> +{
>> +	return container_of(s, struct mem_cgroup, css);
>> +}
>> +
>>  static bool mem_cgroup_is_root(struct mem_cgroup *memcg);
>>  void sock_update_memcg(struct sock *sk)
>>  {
>> @@ -820,7 +826,7 @@ static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
>>  
>>  struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
>>  {
>> -	return container_of(cgroup_subsys_state(cont,
>> +	return mem_cgroup_from_css(cgroup_subsys_state(cont,
>>  				mem_cgroup_subsys_id), struct mem_cgroup,
>>  				css);
>
>Hm?.. Here and below too many args to mem_cgroup_from_css().
>Have you tested the code?

Hi, what's the meaning of "two many"?

cgroup_subsys_state(cont, mem_cgroup_subsys_id) and 
task_subsys_state(p, mem_cgroup_subsys_id) both are 
just one arg in mem_cgroup_from_css. :-)

>
>>  }
>> @@ -835,7 +841,7 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
>>  	if (unlikely(!p))
>>  		return NULL;
>>  
>> -	return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
>> +	return mem_cgroup_from_css(task_subsys_state(p, mem_cgroup_subsys_id),
>>  				struct mem_cgroup, css);
>>  }
>>  
>> @@ -922,7 +928,7 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
>>  		css = css_get_next(&mem_cgroup_subsys, id + 1, &root->css, &id);
>>  		if (css) {
>>  			if (css == &root->css || css_tryget(css))
>> -				memcg = container_of(css,
>> +				memcg = mem_cgroup_from_css(css,
>>  						     struct mem_cgroup, css);
>>  		} else
>>  			id = 0;
>> @@ -2406,7 +2412,7 @@ static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
>>  	css = css_lookup(&mem_cgroup_subsys, id);
>>  	if (!css)
>>  		return NULL;
>> -	return container_of(css, struct mem_cgroup, css);
>> +	return mem_cgroup_from_css(css, struct mem_cgroup, css);
>>  }
>>  
>>  struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
>> -- 
>> 1.7.5.4
>> 
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>
>-- 
> Kirill A. Shutemov