On Thu, Sep 27, 2018 at 10:54:20AM -0600, Logan Gunthorpe wrote: > We create a configfs attribute in each nvme-fabrics target port to > enable p2p memory use. When enabled, the port will only then use the > p2p memory if a p2p memory device can be found which is behind the > same switch hierarchy as the RDMA port and all the block devices in > use. If the user enabled it and no devices are found, then the system > will silently fall back on using regular memory. > > If appropriate, that port will allocate memory for the RDMA buffers > for queues from the p2pmem device falling back to system memory should > anything fail. > > Ideally, we'd want to use an NVME CMB buffer as p2p memory. This would > save an extra PCI transfer as the NVME card could just take the data > out of it's own memory. However, at this time, only a limited number > of cards with CMB buffers seem to be available. > > Signed-off-by: Stephen Bates <sbates@xxxxxxxxxxxx> > Signed-off-by: Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx> > [hch: partial rewrite of the initial code] > Signed-off-by: Christoph Hellwig <hch@xxxxxx> > Signed-off-by: Logan Gunthorpe <logang@xxxxxxxxxxxx> I haven't the necessary hardware to try this out, but looking forward to it in the future. Looks good. Reviewed-by: Keith Busch <keith.busch@xxxxxxxxx>
