[PATCH V2] powerpc/infiniband: Use cache inhibitted and guarded mapping on powerpc

[Jason Gunthorpe]

On Fri, Apr 22, 2016 at 08:47:56AM +1000, Benjamin Herrenschmidt wrote:
> On Wed, 2016-04-20 at 03:58 -0400, Aneesh Kumar K.V wrote:
> > The driver was requesting for a writethrough mapping. But with thoses
> > flags we will end up with a SAO mapping because we now have memory
> > conherence always enabled. ie, the existing mapping will end up with
> > a WIMG value 0b1110 which is Strong Access Order.
> > 
> > Update this to use cache inhibitted guarded mapping
> 
> Why guarded ? If it's performance sensitive (and the driver has
> appropriate barriers where needed), you will get write combining
> without guarded, you won't with it.

This driver uses uncached write combining on x86

Jason