Re: [PATCH 7/8] Scanner changes needed to implement per-container scanner

From: Balbir Singh <balbir@linux.vnet.ibm.com>
To: Pavel Emelianov <xemul@openvz.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Paul Menage <menage@google.com>, Balbir Singh <balbir@in.ibm.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	devel@openvz.org, Kirill Korotaev <dev@openvz.org>
Subject: Re: [PATCH 7/8] Scanner changes needed to implement per-container scanner
Date: Fri, 01 Jun 2007 13:08:03 +0530	[thread overview]
Message-ID: <465FCCDB.5060008@linux.vnet.ibm.com> (raw)
In-Reply-To: <465FCD59.7060301@openvz.org>

Pavel Emelianov wrote:
> Balbir Singh wrote:
>> Andrew Morton wrote:
>>>> +		nr_reclaimed += shrink_zones(priority, zones, sc);
>>>> +		if (sc->cnt == NULL)
>>>> +			shrink_slab(sc->nr_scanned, gfp_mask, lru_pages);
>>> We don't we shrink slab if called to shrink a container.
>>>
>>> This is a fundamental design decision, and a design shortcoming.  A full
>>> discussion of this is absolutely appropriate to the patch changelog. 
>>> Please don't just hide stuff like this in the patch and leave people
>>> wondering, or ignorant.
>> Yes, we don't because we do not account for slab usage right now. We account
>> only for memory allocated to user space. A good fat comment will help here.
>>
>>
> 
> I have already added the comment. But the problem is not in that we
> do not account for kernel memory. Shrinking slabs won't unmap any
> pages from user-space and thus won't help user to charge more. This
> will only make kernel suffer from re-creation of objects.

I meant the same thing. Thanks for adding the comment.

-- 
	Warm Regards,
	Balbir Singh
	Linux Technology Center
	IBM, ISTL