Re: [RFC] [PATCH -mm] cgroup: limit the amount of dirty file pages

[Andrea Righi <righi.andrea@gmail.com>]

kamezawa.hiroyu@jp.fujitsu.com wrote:
> ----- Original Message -----
>> This is a totally experimental patch against 2.6.27-rc5-mm1.
>>
>> It allows to control how much dirty file pages a cgroup can have at any
>> given time. This feature is supposed to be strictly connected to a
>> generic cgroup IO controller (see below).
>>
>> Interface: a new entry "filedirty" is added to the file memory.stat,
>> reporting the number of dirty file pages (in pages), and a new file
>> memory.file_dirty_limit_in_pages is added in the cgroup filesystem to
>> show/set the current limit.
>>
> Before staring patch review, why not dirty_ratio per memcg ?
> Is there difficult implementation issue ?

mmmh.. maybe it's a bit more complex (would add some overhead?) to
translate the limit from dirty_ratio into pages or bytes, because we
need to evaluate it in function of the per-cgroup dirtyable memory (lru
pages and free pages I suppose). Maybe it's enough to implement it
directly in determine_dirtyable_memory().

I can try to implement it and post a new patch.

-Andrea