Re: Use of memmap= to forcibly recover memory in 3GB-4GB range - isthis safe?

From: Yinghai Lu
Date: Wed Jan 16 2013 - 02:02:19 EST


On Tue, Jan 15, 2013 at 6:28 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> On 01/15/2013 05:47 PM, Alex Villacís Lasso wrote:

>> 2) I have recompiled the kernel to support the memtest parameter. When
>> using it, the extra memory segment appears to be as healthy as other
>> areas of memory. However this might only mean that it is wrapping into
>> healthy low RAM.

memtest should print out about the range.

and if you are using 64bit kernel, it should test all memory
except for range with kernel itself.


>>
>> Is my reasoning sane? Is there a way to know, once and for all, whether
>> the extra "memory" is real and safe to use or not?
>
>
> Maybe you can get memtest86+ to test this phantom memory? But yes, it does
> sound like a BIOS bug.

that may not help, because e820 from bios is not right.

Yinghai
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