From: Andrew Morton <akpm@osdl.org>
To: Andreas Romeyke <art1@it-netservice.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: kernel 2.5: mlock broken?
Date: Fri, 8 Aug 2003 14:49:37 -0700 [thread overview]
Message-ID: <20030808144937.6055a798.akpm@osdl.org> (raw)
In-Reply-To: <20030808233213.4ffb2c84.art1@it-netservice.de>
Andreas Romeyke <art1@it-netservice.de> wrote:
>
> Hi folks,
>
> By testing 2.6.0-test2, I detected that the glibc-function mlock(),
> provided by /sys/mlock.h seems to be a deadlock in some cases on 2.5
>
> If you want to lock more memory than physical RAM could be freed, the
> mlock() does not return with an errorcode as under 2.4.21 does.
> The system hangs around. This problem was catched under x86 and s390
> architecture by using Debian distribution (woody and unstable) and
> others with the well known memtest program written by Charles Cazabon
> from http://www.qcc.ca/~charlesc/software/memtester/ (ver. 2.93.1).
>
2.4 kernels have a little check which prevents a single process from
mlocking more than half of physical memory. So you need to run two
processes to kill a 2.4 box with mlock.
Some people want to be able to mlock more memory than that in a single
process, so the check was removed in 2.6. It was pretty pointless.
prev parent reply other threads:[~2003-08-08 22:03 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-08 21:32 kernel 2.5: mlock broken? Andreas Romeyke
2003-08-08 21:49 ` Andrew Morton [this message]
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