Re: [RFC Patch] use MTRR for write combining if PAT is not available

From: Jan Beulich
Date: Wed Oct 21 2009 - 10:10:30 EST


>>> Thomas Schlichter <thomas.schlichter@xxxxxx> 21.10.09 15:45 >>>
>Ingo Molnar wrote:
>> Can we eliminate mtrr_add_unaligned() as Suresh suggested, and still
>> make it work on your testbox?
>
>Yes, I had that in the first place, but Jan suggested to extend it to also
>handle non-aligned, non-power-of-two cases:
> http://marc.info/?l=linux-kernel&m=125541951529918&w=2

I merely pointed out it wouldn't work for unaligned addresses or sizes
passed in.

>So if it's OK for Jan, I'll reduce the functionality again and use mtrr_add()
>instead. Btw. this simply means to drop mtrr_add_unaligned(), all the other
>parts are still required for reference counting and a proper mtrr_del() on file
>close.

I'm perfectly fine with just handling the aligned case, as long as the code
checks that the alignment constraints are met.

Jan

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