linux-kernel - Re: [PATCH mmotm] vmscan: handle may_swap more strictly (Re: [PATCH mmotm] vmscan: fix may

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]

Date:	Tue, 9 Jun 2009 17:19:20 +0900
From:	Minchan Kim <minchan.kim@...il.com>
To:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Cc:	Daisuke Nishimura <nishimura@....nes.nec.co.jp>,
	LKML <linux-kernel@...r.kernel.org>,
	linux-mm <linux-mm@...ck.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Johannes Weiner <hannes@...xchg.org>,
	Balbir Singh <balbir@...ux.vnet.ibm.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
Subject: Re: [PATCH mmotm] vmscan: handle may_swap more strictly (Re: [PATCH 
	mmotm] vmscan: fix may_swap handling for memcg)

On Tue, Jun 9, 2009 at 4:58 PM, KOSAKI
Motohiro<kosaki.motohiro@...fujitsu.com> wrote:
>> Hi, KOSAKI.
>>
>> As you know, this problem caused by if condition(priority) in shrink_zone.
>> Let me have a question.
>>
>> Why do we have to prevent scan value calculation when the priority is zero ?
>> As I know, before split-lru, we didn't do it.
>>
>> Is there any specific issue in case of the priority is zero ?
>
> Yes.
>
> example:
>
> get_scan_ratio() return anon:80%, file=20%. and the system have
> 10000 anon pages and 10000 file pages.
>
> shrink_zone() picked up 8000 anon pages and 2000 file pages.
> it mean 8000 file pages aren't scanned at all.
>
> Oops, it can makes OOM-killer although system have droppable file cache.
>
Hmm..Can that problem be happen in real system ?
The file ratio is big means that file lru list scanning is so big but
rotate is small.
It means file lru have few reclaimable page.

Isn't it ? I am confusing.
Could you elaborate, please if you don't mind ?

-- 
Kinds regards,
Minchan Kim
--
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/