Re: [PATCH 2/2] Make res_counter hierarchical

[Pavel Emelyanov <xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>]

KAMEZAWA Hiroyuki wrote:
> On Tue, 11 Mar 2008 11:15:56 +0300
> Pavel Emelyanov <xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org> wrote:
>>> Hmm? seems strange.
>>>
>>> IMO, a parent's usage is just sum of all childs'.
>>> And, historically, memory overcommit is done agaist "memory usage + swap".
>>>
>>> How about this ?
>>>     <mem_counter_top, swap_counter_top>
>>> 	<mem_counter_sub, swap_counter_sub>
>>> 	<mem_counter_sub, swap_counter_sub>
>>> 	<mem_counter_sub, swap_counter_sub>
>>>
>>>    mem_counter_top.usage == sum of all mem_coutner_sub.usage
>>>    swap_counter_sub.usage = sum of all swap_counter_sub.usage
>> I've misprinted in y tree, sorry.
>> The correct hierarchy as I see it is
>>
> thank you.
> 
>> <mem_couter_0>
>>  + -- <swap_counter_0>
>>  + -- <mem_counter_1>
>>  |     + -- <swap_counter_1>
>>  |     + -- <mem_counter_11>
>>  |     |     + -- <swap_counter_11>
>>  |     + -- <mem_counter_12>
>>  |           + -- <swap_counter_12>
>>  + -- <mem_counter_2>
>>  |     + -- <swap_counter_2>
>>  |     + -- <mem_counter_21>
>>  |     |     + -- <swap_counter_21>
>>  |     + -- <mem_counter_22>
>>  |           + -- <swap_counter_22>
>>  + -- <mem_counter_N>
>>        + -- <swap_counter_N>
>>        + -- <mem_counter_N1>
>>        |     + -- <swap_counter_N1>
>>        + -- <mem_counter_N2>
>>              + -- <swap_counter_N2>
>>
> please let me confirm.
> 
> - swap_counter_X.limit can be defined independent from mem_counter_X.limit ?
> - swap_conter_N1's limit and swap_counter_N's have some relationship ?

No. The mem_counter_N_limit is the limit for all the memory, that the
Nth group consumes. This includes the RSS, page cache and swap for this
group and all the child groups. Since RSS and page cache are accounted
together, this limit tracks the sum of (memory + swap) values over the
subtree started at the given group.

> Thanks,
> -kame
> 
>