Re: ARM kirkwood: 1 Gb memory 25% unusable due to vmalloc region overlap

From: Russell King - ARM Linux
Date: Sat Sep 06 2014 - 14:29:34 EST


On Sat, Sep 06, 2014 at 07:32:07PM +0200, Jurriaan wrote:
> I updated my Qnap TS-212 with 256 Mb memory to a new TS-221 with 1 Gb
> memory.
>
> On booting, I see that a large chunk of that new memory is not used by
> linux:
>
> [ 0.000000] Booting Linux on physical CPU 0x0
> [ 0.000000] Initializing cgroup subsys cpuset
> [ 0.000000] Initializing cgroup subsys cpu
> [ 0.000000] Initializing cgroup subsys cpuacct
> [ 0.000000] Linux version 3.14-2-kirkwood (debian-kernel@xxxxxxxxxxxxxxxx) (gcc version 4.8.3 (Debian 4.8.3-7) ) #1 Debian 3.14.15-2 (2014-08-09)
> [ 0.000000] CPU: Feroceon 88FR131 [56251311] revision 1 (ARMv5TE), cr=00053977
> [ 0.000000] CPU: VIVT data cache, VIVT instruction cache
> [ 0.000000] Machine: QNAP TS-119/TS-219
> [ 0.000000] Ignoring unrecognised tag 0x41000403
> [ 0.000000] Truncating RAM at 20000000-3fffffff to -2f7fffff (vmalloc region overlap).
>
> Whoops!

You can either enable highmem (which has been available on ARM for
ages now, there's little excuse not to use it) or reduce the available
userspace virtual memory by enabling VMSPLIT_2G.

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