Re: x86_64: wrong DirectMap kB

From: Hugh Dickins
Date: Mon Oct 01 2012 - 11:24:23 EST


On Mon, 1 Oct 2012, Jamie Gloudon wrote:
>
> Interesting. I am able to reproduce the same problem as you using mem=700M, which shows:
>
> DirectMap4k: 4096 kB
> DirectMap2M: 18446744073709547520 kB
>
> However, it appears to be normal without the boot parameter:
>
> DirectMap4k: 4096 kB
> DirectMap2M: 15708160 kB

It appears to be normal because the calculations haven't wrapped around,
but if you compare with 3.4 or before, I think you'll find that it
still adds up to too little.

>
> What does your output looks like with the full amount on 3.6?

On 3.6:

MemTotal: 8060528 kB
...
DirectMap4k: 2048 kB
DirectMap2M: 7229440 kB

So it's showing significantly less direct mapped than is included
in MemTotal (which itself omits some areas of reserved memory).

Whereas on 3.4:

MemTotal: 8060760 kB
...
DirectMap4k: 4096 kB
DirectMap2M: 8275968 kB

Hugh
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