Re: [PATCH 0/3] memblock related top down

From: H. Peter Anvin
Date: Tue Dec 28 2010 - 17:10:19 EST


On 12/28/2010 01:36 PM, Yinghai Lu wrote:
> On Tue, Dec 28, 2010 at 12:21 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
>> On 12/17/2010 04:58 PM, Yinghai Lu wrote:
>>> Please check
>>>
>>> Those three patches to make memblock allocation more top to down.
>>>
>>
>> Please explain what you mean with "more top to down". Not what the code
>> does, but what is the goal of the patchset.
>
> for example first node with 16g ram, it is into two parts: [0, 2g),
> and [4g, 18g).
>
> alloc_bootmem will get allocation from [0, 2g) always until we have
> can not find more.
>
> with third patch, it will try to get from [4g, 18g) at first.
>
> second patch is need to applied before third patch, because old way
> happenly get under 4g for generic bootmem under 4g
>
> First one is trying not to put page table for [0, 4g) under 512M.
>

The goal of this is to free up low memory for DMA and kdump, I presume?

-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.

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