2005-10-10 14:07:10

by Vivek Kutal

[permalink] [raw]
Subject: ZONE_HIGHMEM query

Hello Everyone ,
All books that I have read say that the concept of ZONE_HIGHMEM is
introduced because some architectures cannot directly map memory
beyond 896MB (x86).

My question is What is direct mapping(does it mean, same virtual
address and physical address) and why cant a architecture directly map
a particular region in the memory?



--
Thanks and Regards
Vivek Kutal
http://vivekkutal.blogspot.com

"Live as if you were to die tomorrow. Learn as if you were
to live forever."


2005-10-10 17:01:05

by Parag Warudkar

[permalink] [raw]
Subject: Re: ZONE_HIGHMEM query

KernelTrap has an good article explaining the details of HIGHMEM - http://kerneltrap.org/node/2450

Parag


> Hello Everyone ,
> All books that I have read say that the concept of ZONE_HIGHMEM is
> introduced because some architectures cannot directly map memory
> beyond 896MB (x86).
>
> My question is What is direct mapping(does it mean, same virtual
> address and physical address) and why cant a architecture directly map
> a particular region in the memory?
>
>
>
> --
> Thanks and Regards
> Vivek Kutal
> http://vivekkutal.blogspot.com
>
> "Live as if you were to die tomorrow. Learn as if you were
> to live forever."
> -
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