From 20cf4e026730104892fa1268de0371a631cee294 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Mon, 29 Jul 2019 13:22:09 -0400 Subject: rdma: Enable ib_alloc_cq to spread work over a device's comp_vectors MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Send and Receive completion is handled on a single CPU selected at the time each Completion Queue is allocated. Typically this is when an initiator instantiates an RDMA transport, or when a target accepts an RDMA connection. Some ULPs cannot open a connection per CPU to spread completion workload across available CPUs and MSI vectors. For such ULPs, provide an API that allows the RDMA core to select a completion vector based on the device's complement of available comp_vecs. ULPs that invoke ib_alloc_cq() with only comp_vector 0 are converted to use the new API so that their completion workloads interfere less with each other. Suggested-by: Håkon Bugge Signed-off-by: Chuck Lever Reviewed-by: Leon Romanovsky Cc: Cc: Link: https://lore.kernel.org/r/20190729171923.13428.52555.stgit@manet.1015granger.net Signed-off-by: Doug Ledford --- drivers/infiniband/core/cq.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'drivers/infiniband/core/cq.c') diff --git a/drivers/infiniband/core/cq.c b/drivers/infiniband/core/cq.c index 7c599878ccf7..bbfded6d5d3d 100644 --- a/drivers/infiniband/core/cq.c +++ b/drivers/infiniband/core/cq.c @@ -252,6 +252,34 @@ out_free_cq: } EXPORT_SYMBOL(__ib_alloc_cq_user); +/** + * __ib_alloc_cq_any - allocate a completion queue + * @dev: device to allocate the CQ for + * @private: driver private data, accessible from cq->cq_context + * @nr_cqe: number of CQEs to allocate + * @poll_ctx: context to poll the CQ from + * @caller: module owner name + * + * Attempt to spread ULP Completion Queues over each device's interrupt + * vectors. A simple best-effort mechanism is used. + */ +struct ib_cq *__ib_alloc_cq_any(struct ib_device *dev, void *private, + int nr_cqe, enum ib_poll_context poll_ctx, + const char *caller) +{ + static atomic_t counter; + int comp_vector = 0; + + if (dev->num_comp_vectors > 1) + comp_vector = + atomic_inc_return(&counter) % + min_t(int, dev->num_comp_vectors, num_online_cpus()); + + return __ib_alloc_cq_user(dev, private, nr_cqe, comp_vector, poll_ctx, + caller, NULL); +} +EXPORT_SYMBOL(__ib_alloc_cq_any); + /** * ib_free_cq_user - free a completion queue * @cq: completion queue to free. -- cgit