linux-kernel - Re: RFT: updatedb "morning after" problem [was: Re: -mm merge plans for 2.6.23]

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:	Fri, 27 Jul 2007 20:16:32 +0200
From:	Rene Herman <rene.herman@...il.com>
To:	Daniel Hazelton <dhazelton@...er.net>
CC:	Mike Galbraith <efault@....de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Ingo Molnar <mingo@...e.hu>,
	Frank Kingswood <frank@...gswood-consulting.co.uk>,
	Andi Kleen <andi@...stfloor.org>,
	Nick Piggin <nickpiggin@...oo.com.au>,
	Ray Lee <ray-lk@...rabbit.org>,
	Jesper Juhl <jesper.juhl@...il.com>,
	ck list <ck@....kolivas.org>, Paul Jackson <pj@....com>,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: RFT: updatedb "morning after" problem [was: Re: -mm merge plans
 for 2.6.23]

On 07/27/2007 07:45 PM, Daniel Hazelton wrote:

> Updatedb or another process that uses the FS heavily runs on a users
> 256MB P3-800 (when it is idle) and the VFS caches grow, causing memory
> pressure that causes other applications to be swapped to disk. In the
> morning the user has to wait for the system to swap those applications
> back in.
> 
> Questions about it:
> Q) Does swap-prefetch help with this? 
> A) [From all reports I've seen (*)] Yes, it does. 

No it does not. If updatedb filled memory to the point of causing swapping 
(which noone is reproducing anyway) it HAS FILLED MEMORY and swap-prefetch 
hasn't any memory to prefetch into -- updatedb itself doesn't use any 
significant memory.

Here's swap-prefetch's author saying the same:

http://lkml.org/lkml/2007/2/9/112

| It can't help the updatedb scenario. Updatedb leaves the ram full and
| swap prefetch wants to cost as little as possible so it will never
| move anything out of ram in preference for the pages it wants to swap
| back in.

Now please finally either understand this, or tell us how we're wrong.

Rene.

-
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/