Re: [PATCH 3/3] x86, crash: Allocate enough low-mem when crashkernel=high

From: Borislav Petkov
Date: Fri Jan 23 2015 - 12:02:55 EST


On Tue, Jan 06, 2015 at 03:51:14PM +0100, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@xxxxxxx>
>
> When the crashkernel is loaded above 4GiB in memory the
> first kernel only allocates 72MiB of low-memory for the DMA
> requirements of the second kernel. On systems with many
> devices this is not enough and causes device driver
> initialization errors and failed crash dumps. Set this
> default value to 256MiB to make sure there is enough memory

This upper limit of 256 looks arbitrary. Are we going to raise it a
couple of years from now if it becomes insufficient then?

It probably won't be easy but is there some more reliable way to
allocate enough memory for DMA on a say per-system basis or whatever...?
Probably not but let me ask it anyway.

--
Regards/Gruss,
Boris.

ECO tip #101: Trim your mails when you reply.
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