Re: [PATCH] introduce config option to disable DMA zone on i386

From: Arjan van de Ven
Date: Thu Dec 28 2006 - 12:45:30 EST

On Thu, 2006-12-28 at 15:03 -0200, Marcelo Tosatti wrote:
> Hi,
> The following patch adds a config option to get rid of the DMA zone on i386.
> Architectures with devices that have no addressing limitations (eg. PPC)
> already work this way.
> This is useful for custom kernel builds where the developer is certain that
> there are no address limitations.
> For example, the OLPC machine contains:
> - USB devices
> - no floppy
> - no address limited PCI devices
> - no floppy
> A unified zone simplifies VM reclaiming work, and also simplifies OOM
> killer heuristics (no need to deal with OOM on the DMA zone).
> Comments?


since one gets random corruption if a user gets this wrong, at least
make things like floppy and all CONFIG_ISA stuff conflict with this
option.... without that your patch feels like a walking time bomb...
(and please include all PCI drivers that only can do 24 bit or 28bit
or .. non-32bit dma as well)

Arjan van de Ven

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