Re: [PATCH 2/7] memcg: remove MEMCG_NR_FILE_MAPPED

[Sha Zhengju <handai.szj@gmail.com>]

On 07/10/2012 05:01 AM, Greg Thelen wrote:
> On Thu, Jun 28 2012, Sha Zhengju wrote:
>
>> From: Sha Zhengju<handai.szj@taobao.com>
>>
>> While accounting memcg page stat, it's not worth to use MEMCG_NR_FILE_MAPPED
>> as an extra layer of indirection because of the complexity and presumed
>> performance overhead. We can use MEM_CGROUP_STAT_FILE_MAPPED directly.
>>
>> Signed-off-by: Sha Zhengju<handai.szj@taobao.com>
>> ---
>>   include/linux/memcontrol.h |   25 +++++++++++++++++--------
>>   mm/memcontrol.c            |   24 +-----------------------
>>   mm/rmap.c                  |    4 ++--
>>   3 files changed, 20 insertions(+), 33 deletions(-)
>>
>> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
>> index 83e7ba9..20b0f2d 100644
>> --- a/include/linux/memcontrol.h
>> +++ b/include/linux/memcontrol.h
>> @@ -27,9 +27,18 @@ struct page_cgroup;
>>   struct page;
>>   struct mm_struct;
>>
>> -/* Stats that can be updated by kernel. */
>> -enum mem_cgroup_page_stat_item {
>> -	MEMCG_NR_FILE_MAPPED, /* # of pages charged as file rss */
>> +/*
>> + * Statistics for memory cgroup.
>> + */
>> +enum mem_cgroup_stat_index {
>> +	/*
>> +	 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
>> +	 */
>> +	MEM_CGROUP_STAT_CACHE, 	   /* # of pages charged as cache */
>> +	MEM_CGROUP_STAT_RSS,	   /* # of pages charged as anon rss */
>> +	MEM_CGROUP_STAT_FILE_MAPPED,  /* # of pages charged as file rss */
>> +	MEM_CGROUP_STAT_SWAP, /* # of pages, swapped out */
>> +	MEM_CGROUP_STAT_NSTATS,
>>   };
> Nit.  Moving mem_cgroup_stat_index from memcontrol.c to memcontrol.h is
> fine with me.  But this does increase the distance between related
> defintions of definition mem_cgroup_stat_index and
> mem_cgroup_stat_names.  These two lists have to be kept in sync.  So it
> might help to add a comment to both indicating their relationship so we
> don't accidentally modify the enum without updating the dependent string
> table.
>
> Otherwise, looks good.
>
> Reviewed-by: Greg Thelen<gthelen@google.com>

Sorry for the delay.
OK, I'll add some comment here. Thanks for reminding!

Thanks,
Sha