Re: [RFC: DMA_PMD 00/22] DMA_PMD: PMD_SIZE-backed IO buffer pools

[Jason Gunthorpe]

On Sat, Oct 17, 2026 at 07:11:28PM +0200, Luigi Rizzo wrote:
> > We should probably just find a way to describe that this is a POOL that focuses
> > on physical contiguity in some configured granularity.
> 
> Before embarking in a global renaming, I would like to get opinions on
> acceptable alternative names (possibly with a short prefix usable for
> identifiers in the code). I could think of the following
> 
> DMA_PMAP (for PreMapped or Persistent Mapped)
> or, ahemm...
> DMA_PISA (Pooled IOMMU Superpage Allocator)
> both using dmap_ for internal name prefixes

Can someone explain what outside netdev would use this? And why you
couldn't do this in the netdev page pool?

It is not a common workload to have the DMA allocator be the one that
allocates the memory. Usually we are DMA'ing from memory that was
allocated someplace else.

I think Robin is right, this is just a special case of the dma pool,
and it certainly shouldn't be something as grandiose as a subsystem..

Jason