Commit 24c5dc66 authored by Sagi Grimberg's avatar Sagi Grimberg Committed by Doug Ledford

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: default avatarJens Axboe <>
Reviewed-by: default avatarChristoph Hellwig <>
Reviewed-by: default avatarMax Gurtovoy <>
Signed-off-by: default avatarSagi Grimberg <>
Signed-off-by: default avatarDoug Ledford <>
parent 40b24403
......@@ -206,4 +206,9 @@ config BLK_MQ_VIRTIO
depends on BLOCK && VIRTIO
default y
config BLK_MQ_RDMA
depends on BLOCK && INFINIBAND
default y
source block/Kconfig.iosched
......@@ -29,6 +29,7 @@ obj-$(CONFIG_BLK_CMDLINE_PARSER) += cmdline-parser.o
obj-$(CONFIG_BLK_DEV_INTEGRITY) += bio-integrity.o blk-integrity.o t10-pi.o
obj-$(CONFIG_BLK_MQ_PCI) += blk-mq-pci.o
obj-$(CONFIG_BLK_MQ_VIRTIO) += blk-mq-virtio.o
obj-$(CONFIG_BLK_MQ_RDMA) += blk-mq-rdma.o
obj-$(CONFIG_BLK_DEV_ZONED) += blk-zoned.o
obj-$(CONFIG_BLK_WBT) += blk-wbt.o
obj-$(CONFIG_BLK_DEBUG_FS) += blk-mq-debugfs.o
* 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 <linux/blk-mq.h>
#include <linux/blk-mq-rdma.h>
#include <rdma/ib_verbs.h>
* 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;
return blk_mq_map_queues(set);
struct blk_mq_tag_set;
struct ib_device;
int blk_mq_rdma_map_queues(struct blk_mq_tag_set *set,
struct ib_device *dev, int first_vec);
#endif /* _LINUX_BLK_MQ_RDMA_H */
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