On 01/03/18 04:49 PM, Keith Busch wrote:

On Thu, Mar 01, 2018 at 11:00:51PM +0000, Stephen  Bates wrote:

quoted

P2P is about offloading the memory and PCI subsystem of the host CPU
and this is achieved no matter which p2p_dev is used.

Even within a device, memory attributes for its various regions may not be
the same. There's a meaningful difference between writing to an NVMe CMB
vs PMR, and a single device could have both. We don't want to lump these
all together without knowing which region you're allocating from, right?

Yes, PMRs are a whole other beast. I have no idea what anyone is going 
to actually do with those yet. But no one is proposing to publish them 
as p2pmem with this code.

Logan