Re: [Intel IOMMU 06/10] Avoid memory allocation failures in dmamap api calls

[Arjan van de Ven]

On Tue, 2007-06-19 at 16:34 -0700, Christoph Lameter wrote:
> On Tue, 19 Jun 2007, Arjan van de Ven wrote:
> 
> > > Otherwise you are locked into the use of GFP_ATOMIC.
> > 
> > all callers pretty much are either in irq context or with spinlocks held. Good
> > luck..... it's also called primarily from the PCI DMA API which doesn't take a
> > gfp_t argument in the first place...
> > 
> > so I'm not seeing the point.
> 
> Hmmm... From my superficial look at things it seems that one could avoid 
> GFP_ATOMIC at times. 

by changing ALL drivers. And then you realize the common scenario is
that it's taken in irq context ;)

> I do not know too much about the driver though but it 
> seems a bit restrictive to always do GFP_ATOMIC allocs.

the only alternative to GFP_ATOMIC is GFP_NOIO which is... barely
better. And then add that it can be used only sporadic...
feel free to first change all the drivers.. once the callers of these
functions have a gfp_t then I'm sure Anil will be happy to take one of
those as well ;-)

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