On Mon, Aug 20, 2018 at 01:54:20PM -0700, Sagi Grimberg wrote: > nvme-rdma attempts to map queues based on irq vector affinity. > However, for some devices, completion vector irq affinity is > configurable by the user which can break the existing assumption > that irq vectors are optimally arranged over the host cpu cores. > > So we map queues in two stages: > First map queues according to corresponding to the completion > vector IRQ affinity taking the first cpu in the vector affinity map. > if the current irq affinity is arranged such that a vector is not > assigned to any distinct cpu, we map it to a cpu that is on the same > node. If numa affinity can not be sufficed, we map it to any unmapped > cpu we can find. Then, map the remaining cpus in the possible cpumap > naively. I guess this way still can't fix the request allocation crash issue triggered by using blk_mq_alloc_request_hctx(), in which one hw queue may not be mapped from any online CPU. Maybe this patch isn't for this issue, but it is closely related. Thanks, Ming
