[dm-devel] Re: a room for blkio-cgroup in struct page_cgroup

["KAMEZAWA Hiroyuki" <kamezawa hiroyu jp fujitsu com>]

Ryo Tsuruta wrote:
> Hi Kamezawa-san,
>
> As you wrote before (http://lkml.org/lkml/2009/7/22/65)
>> To be honest, what I expected in these days for people of blockio
>> cgroup is like following for getting room for themselves.
> <<snip>>
>> --- mmotm-2.6.31-Jul16.orig/include/linux/page_cgroup.h
>> +++ mmotm-2.6.31-Jul16/include/linux/page_cgroup.h
>> @@ -13,7 +13,7 @@
>>  struct page_cgroup {
>>       unsigned long flags;
>>       struct mem_cgroup *mem_cgroup;
>> -     struct page *page;
>> +     /* block io tracking will use extra unsigned long bytes */
>>       struct list_head lru;       /* per cgroup LRU list */
>> };
>
> Have you already added a room for blkio_cgroup in struct page_cgroup?
No.

> If not, I would like you to apply the above change to mmotm.
>
Plz wait until October. We're deadly busy and some amount of more important
patches are piled up in front of us. I have no objections if you add
a pointer or id  because I know I can reduce 8(4)bytes later.
Just add (a small) member for a while and ignore page_cgroup's size.
I'll fix later.

> The latest blkio-cgroup has reflected the comments you pointed out.
> I would also like you to give me any comments on it and consider
> merging blkio-cgroup to mmotm.
>
BTW, do you all have cosensus about implementation ?

Bye,
-Kame