Messages in this thread | | | Subject | RE: Can Linux live without DMA zone? | Date | Thu, 2 Nov 2006 11:43:38 +0800 | From | "Conke Hu" <> |
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It seems a good idea. Is dma zone is still necessay on most modern computers?
Best regards, Conke @ AMD, Inc.
-----Original Message----- From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Jun Sun Sent: 2006年11月2日 10:16 To: linux-kernel@vger.kernel.org Subject: Can Linux live without DMA zone?
I am trying to reserve a block of memory (>16MB) starting from 0 and hide it from kernel. A consequence is that DMA zone now has size 0. That causes many drivers to grief (OOMs).
I see two ways out:
1. Modify individual drivers and convince them not to alloc with GFP_DMA. I have been trying to do this but do not seem to see an end of it. :)
2. Simply lie and increase MAX_DMA_ADDRESS to really big (like 1GB) so that the whole memory region belongs to DMA zone.
#2 sounds pretty hackish. I am sure something bad will happen sooner or later (like what?). But so far it appears to be working fine.
The fundamental question is: Has anybody tried to run Linux without 0 sized DMA zone before? Am I doing something that nobody has done before (which is something really hard to believe these days with Linux :P)?
Cheers.
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