From 24c5dc6610e8a3764fcb885cc3284c12ff1513de Mon Sep 17 00:00:00 2001 From: Sagi Grimberg Date: Thu, 13 Jul 2017 11:09:43 +0300 Subject: block: Add rdma affinity based queue mapping helper Like pci and virtio, we add a rdma helper for affinity spreading. This achieves optimal mq affinity assignments according to the underlying rdma device affinity maps. Reviewed-by: Jens Axboe Reviewed-by: Christoph Hellwig Reviewed-by: Max Gurtovoy Signed-off-by: Sagi Grimberg Signed-off-by: Doug Ledford --- block/blk-mq-rdma.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 block/blk-mq-rdma.c (limited to 'block/blk-mq-rdma.c') diff --git a/block/blk-mq-rdma.c b/block/blk-mq-rdma.c new file mode 100644 index 000000000000..996167f1de18 --- /dev/null +++ b/block/blk-mq-rdma.c @@ -0,0 +1,52 @@ +/* + * Copyright (c) 2017 Sagi Grimberg. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ +#include +#include +#include + +/** + * blk_mq_rdma_map_queues - provide a default queue mapping for rdma device + * @set: tagset to provide the mapping for + * @dev: rdma device associated with @set. + * @first_vec: first interrupt vectors to use for queues (usually 0) + * + * This function assumes the rdma device @dev has at least as many available + * interrupt vetors as @set has queues. It will then query it's affinity mask + * and built queue mapping that maps a queue to the CPUs that have irq affinity + * for the corresponding vector. + * + * In case either the driver passed a @dev with less vectors than + * @set->nr_hw_queues, or @dev does not provide an affinity mask for a + * vector, we fallback to the naive mapping. + */ +int blk_mq_rdma_map_queues(struct blk_mq_tag_set *set, + struct ib_device *dev, int first_vec) +{ + const struct cpumask *mask; + unsigned int queue, cpu; + + for (queue = 0; queue < set->nr_hw_queues; queue++) { + mask = ib_get_vector_affinity(dev, first_vec + queue); + if (!mask) + goto fallback; + + for_each_cpu(cpu, mask) + set->mq_map[cpu] = queue; + } + + return 0; + +fallback: + return blk_mq_map_queues(set); +} +EXPORT_SYMBOL_GPL(blk_mq_rdma_map_queues); -- cgit