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

["H. Peter Anvin" <hpa@zytor.com>]

On 02/03/2011 03:25 AM, Stefano Stabellini wrote:
>>
>> How on Earth would you end up with a reserved region *inside the BRK*?
> 
> I think in practice you cannot, but you can have reserved regions at
> _end, that is the main problem I am trying to solve.
> If we have a reserved region at _end and _end is not PMD aligned, then
> we have a problem.
> 
> I thought that checking for reserved regions before destroying the
> mapping would be a decent solution (because it wouldn't affect the
> normal case); so I ended up checking between _brk_end and _end too.
> 
> Other alternative solutions I thought about but that I discarded because
> they also affect the normal case are:
> 
> - never destroy mappings that could go over _end;
> - always PMD align _end.
> 
> If none of the above are acceptable, I welcome other suggestions :-)
> 

Sounds like the code does the right thing, but the description needs to
be improved.

	-hpa


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