Re: [PATCH] x86/mm/init: respect memblock reserved regions when destroyingmappings

From: Yinghai Lu
Date: Thu Feb 10 2011 - 18:58:07 EST


On 02/10/2011 03:48 PM, Jeremy Fitzhardinge wrote:
> On 02/08/2011 11:34 AM, H. Peter Anvin wrote:
>> On 02/07/2011 07:12 PM, Yinghai Lu wrote:
>>> why punishing native path with those checking?
>>>
>> What happens if you end up with a reserved range in an unfortunate place
>> on real hardware?
>
> Yes, exactly. The reserved region code isn't very useful if you can't
> rely on it to reserve stuff.

assume context is under:
moving cleanup_highmap() down after brk is concluded, and check memblock_reserved there.

one case for that: native path, bootloader could put initrd under 512M. and it is with memblock reserved.
if we check those range with memblock_reserved, initial kernel mapping will not be cleaned up.

or worse if we are checking if there is any range from __pa(_brk_end) to 512M is with memblock reserved to decide
if we need to clean-up highmap. it will skip for whole range.

Yinghai
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