From: kamezawa.hiroyu@jp.fujitsu.com
Message-ID: <11706925.1213605137616.kamezawa.hiroyu@jp.fujitsu.com>
Date: Mon, 16 Jun 2008 17:32:17 +0900 (JST)
To: Pavel Emelyanov <xemul@openvz.org>
Subject: Re: Re: [PATCH 1/6] res_counter:  handle limit change
Cc: kamezawa.hiroyu@jp.fujitsu.com, linux-mm@kvack.org,
       LKML <linux-kernel@vger.kernel.org>, menage@google.com,
       balbir@linux.vnet.ibm.com, yamamoto@valinux.co.jp,
       nishimura@mxp.nes.nec.co.jp, lizf@cn.fujitsu.com
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----- Original Message -----

>kamezawa.hiroyu@jp.fujitsu.com wrote:
>> ----- Original Message -----
>> 
>>>> I think when I did all in memcg, someone will comment that "why do that
>>>> all in memcg ? please implement generic one to avoid code duplication"
>>> Hm... But we're choosing between
>>>
>>> sys_write->xxx_cgroup_write->res_counter_set_limit->xxx_cgroup_call
>>>
>>> and
>>>
>>> sys_write->xxx_cgroup_write->res_counter_set_limit
>>>                           ->xxx_cgroup_call
>>>
>>> With the sizeof(void *)-bytes difference in res_counter, nNo?
>>>
>> I can't catch what you mean. What is res_counter_set_limit here ?
>
>It's res_counter_resize_limit from your patch, sorry for the confusion.
>
>> (my patche's ?) and what is sizeof(void *)-bytes ?
>
>I meant, that we have to add 4 bytes (8 on 64-bit arches) on the
>struct res_counter to store the pointer on the res_counter_ops.
>
Okay, maye all you want is "don't increase the size of res_counter"

>> Is it so strange to add following algorithm in res_counter?
>> ==
>> set_limit -> fail -> shrink -> set limit -> fail ->shrink
>> -> success -> return 0
>> ==
>> I think this is enough generic.
>
>It is, but my point is - we're calling the set_limit (this is a
>res_counter_resize_limit from your patch, sorry for the confusion again)
>routine right from the cgroup's write callback and thus can call
>the desired "ops->shrink_usage" directly, w/o additional level of
>indirection.
>
Hmm, to do that, I'd like to remove strategy function from res_counter.
Ok? 

Thanks,
-Kame
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