linux-kernel - Re: [PATCH 0/3] Reduce watermark-related problems with the per-cpu allocator V2

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 for Android: free password hash cracker in your pocket

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

Date:	Mon, 23 Aug 2010 08:38:25 -0500 (CDT)
From:	Christoph Lameter <cl@...ux.com>
To:	Mel Gorman <mel@....ul.ie>
cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Linux Kernel List <linux-kernel@...r.kernel.org>,
	linux-mm@...ck.org, Rik van Riel <riel@...hat.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Minchan Kim <minchan.kim@...il.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Subject: Re: [PATCH 0/3] Reduce watermark-related problems with the per-cpu
 allocator V2

On Mon, 23 Aug 2010, Mel Gorman wrote:

> > The maximum time for which the livelock can exists is the vm stat
> > interval. By default the counters are brought up to date at least once per
> > second or if a certain delta was violated. Drifts are controlled by the
> > delta configuration.
> >
>
> While there is a maximum time (2 seconds I think) the drift can exist
> in, a machine under enough pressure can make a mess of the watermarks
> during that time. If it wasn't the case, these livelocks with 0 pages
> free wouldn't be happening.

So because we go way beyond the watermarks we reach a state in which a
livelock exists that does not go away when the counters are finally
updated?


--
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/