linux-kernel - Re: The performance and behaviour of the anti-fragmentation related patches

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, 02 Mar 2007 16:19:19 -0500
From:	Rik van Riel <riel@...hat.com>
To:	Bill Irwin <bill.irwin@...cle.com>, Rik van Riel <riel@...hat.com>,
	Christoph Lameter <clameter@...r.sgi.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Mel Gorman <mel@...net.ie>, npiggin@...e.de, mingo@...e.hu,
	jschopp@...tin.ibm.com, arjan@...radead.org,
	torvalds@...ux-foundation.org, mbligh@...igh.org,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: The performance and behaviour of the anti-fragmentation related
 patches

Bill Irwin wrote:
> On Fri, Mar 02, 2007 at 01:23:28PM -0500, Rik van Riel wrote:
>> With 32 CPUs diving into the page reclaim simultaneously,
>> each trying to scan a fraction of memory, this is disastrous
>> for performance.  A 256GB system should be even worse.
> 
> Thundering herds of a sort pounding the LRU locks from direct reclaim
> have set off the NMI oopser for users here.

Ditto here.

The main reason they end up pounding the LRU locks is the
swappiness heuristic.  They scan too much before deciding
that it would be a good idea to actually swap something
out, and with 32 CPUs doing such scanning simultaneously...

-- 
Politics is the struggle between those who want to make their country
the best in the world, and those who believe it already is.  Each group
calls the other unpatriotic.
-
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/