linux-kernel - Re: [RFC 2/3] vmscan hook

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4F182BF3.7050809@redhat.com>
Date:	Thu, 19 Jan 2012 09:42:59 -0500
From:	Rik van Riel <riel@...hat.com>
To:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
CC:	Minchan Kim <minchan@...nel.org>, linux-mm <linux-mm@...ck.org>,
	LKML <linux-kernel@...r.kernel.org>, leonid.moiseichuk@...ia.com,
	penberg@...nel.org, mel@....ul.ie, rientjes@...gle.com,
	KOSAKI Motohiro <kosaki.motohiro@...il.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Marcelo Tosatti <mtosatti@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Ronen Hod <rhod@...hat.com>
Subject: Re: [RFC 2/3] vmscan hook

On 01/18/2012 09:25 PM, KAMEZAWA Hiroyuki wrote:
> On Wed, 18 Jan 2012 09:17:17 -0500
> Rik van Riel<riel@...hat.com>  wrote:
>
>> On 01/17/2012 07:18 PM, KAMEZAWA Hiroyuki wrote:
>>> On Wed, 18 Jan 2012 08:08:01 +0900
>>> Minchan Kim<minchan@...nel.org>   wrote:
>>>
>>>>>>> 2. can't we measure page-in/page-out distance by recording something ?
>>>>>>
>>>>>> I can't understand your point. What's relation does it with swapout prevent?
>>>>>>
>>>>>
>>>>> If distance between pageout ->   pagein is short, it means thrashing.
>>>>> For example, recoding the timestamp when the page(mapping, index) was
>>>>> paged-out, and check it at page-in.
>>>>
>>>> Our goal is prevent swapout. When we found thrashing, it's too late.
>>>
>>> If you want to prevent swap-out, don't swapon any. That's all.
>>> Then, you can check the number of FILE_CACHE and have threshold.
>>
>> I think you are getting hung up on a word here.
>>
>> As I understand it, the goal is to push out the point where
>> we start doing heavier swap IO, allowing us to overcommit
>> memory more heavily before things start really slowing down.
>>
>
> Yes.
>
> Hmm, considering that the issue is slow down,
>
> time values as
>
> - 'cpu time used for memory reclaim'
> - 'latency of page allocation'
> - 'application execution speed' ?
>
> may be a better score to see rather than just seeing lru's stat.

I believe those all qualify as "too late".

We want to prevent things from becoming bad, for as long
as we (easily) can.

-- 
All rights reversed
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/