On Thu, Nov 15, 2018 at 7:02 AM Keith Busch <keith.busch@xxxxxxxxx> wrote: > > On Thu, Nov 15, 2018 at 05:57:10AM -0800, Matthew Wilcox wrote: > > On Wed, Nov 14, 2018 at 03:49:14PM -0700, Keith Busch wrote: > > > Memory-only nodes will often have affinity to a compute node, and > > > platforms have ways to express that locality relationship. > > > > > > A node containing CPUs or other DMA devices that can initiate memory > > > access are referred to as "memory iniators". A "memory target" is a > > > node that provides at least one phyiscal address range accessible to a > > > memory initiator. > > > > I think I may be confused here. If there is _no_ link from node X to > > node Y, does that mean that node X's CPUs cannot access the memory on > > node Y? In my mind, all nodes can access all memory in the system, > > just not with uniform bandwidth/latency. > > The link is just about which nodes are "local". It's like how nodes have > a cpulist. Other CPUs not in the node's list can acces that node's memory, > but the ones in the mask are local, and provide useful optimization hints. > > Would a node mask would be prefered to symlinks? I think that would be more flexible, because the set of initiators that may have "best" or "local" access to a target may be more than 1.
