Re: [PATCH v2 10/10] nvmet: Optionally use PCI P2P memory

Logan Gunthorpe
2018-03-01T23:52:23Z

On 01/03/18 04:49 PM, Keith Busch wrote:
> On Thu, Mar 01, 2018 at 11:00:51PM +0000, Stephen Bates wrote:
>>
>> 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