Am 28.03.2018 um 17:47 schrieb Logan Gunthorpe: > > On 28/03/18 09:07 AM, Christian König wrote: >> Am 28.03.2018 um 14:38 schrieb Christoph Hellwig: >>> On Sun, Mar 25, 2018 at 12:59:54PM +0200, Christian König wrote: >>>> From: "wdavis at nvidia.com" <wdavis at nvidia.com> >>>> >>>> Add an interface to find the first device which is upstream of both >>>> devices. >>> Please work with Logan and base this on top of the outstanding peer >>> to peer patchset. >> Can you point me to that? The last code I could find about that was from >> 2015. > The latest posted series is here: > > https://lkml.org/lkml/2018/3/12/830 > > However, we've made some significant changes to the area that's similar > to what you are doing. You can find lasted un-posted here: > > https://github.com/sbates130272/linux-p2pmem/tree/pci-p2p-v4-pre2 > > Specifically this function would be of interest to you: > > https://github.com/sbates130272/linux-p2pmem/blob/0e9468ae2a5a5198513dd12990151e09105f0351/drivers/pci/p2pdma.c#L239 > > However, the difference between what we are doing is that we are > interested in the distance through the common upstream device and you > appear to be finding the actual common device. Yeah, that looks very similar to what I picked up from the older patches, going to read up on that after my vacation. Just in general why are you interested in the "distance" of the devices? And BTW: At least for writes that Peer 2 Peer transactions between different root complexes work is actually more common than the other way around. So I'm a bit torn between using a blacklist or a whitelist. A whitelist is certainly more conservative approach, but that could get a bit long. Thanks, Christian. > > Thanks, > > Logan
