| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * CPU <-> hardware queue mapping helpers |
| * |
| * Copyright (C) 2013-2014 Jens Axboe |
| */ |
| #include <linux/kernel.h> |
| #include <linux/threads.h> |
| #include <linux/module.h> |
| #include <linux/mm.h> |
| #include <linux/smp.h> |
| #include <linux/cpu.h> |
| |
| #include <linux/blk-mq.h> |
| #include "blk.h" |
| #include "blk-mq.h" |
| |
| static int cpu_to_queue_index(struct blk_mq_queue_map *qmap, |
| unsigned int nr_queues, const int cpu) |
| { |
| return qmap->queue_offset + (cpu % nr_queues); |
| } |
| |
| static int get_first_sibling(unsigned int cpu) |
| { |
| unsigned int ret; |
| |
| ret = cpumask_first(topology_sibling_cpumask(cpu)); |
| if (ret < nr_cpu_ids) |
| return ret; |
| |
| return cpu; |
| } |
| |
| int blk_mq_map_queues(struct blk_mq_queue_map *qmap) |
| { |
| unsigned int *map = qmap->mq_map; |
| unsigned int nr_queues = qmap->nr_queues; |
| unsigned int cpu, first_sibling; |
| |
| for_each_possible_cpu(cpu) { |
| /* |
| * First do sequential mapping between CPUs and queues. |
| * In case we still have CPUs to map, and we have some number of |
| * threads per cores then map sibling threads to the same queue |
| * for performance optimizations. |
| */ |
| if (cpu < nr_queues) { |
| map[cpu] = cpu_to_queue_index(qmap, nr_queues, cpu); |
| } else { |
| first_sibling = get_first_sibling(cpu); |
| if (first_sibling == cpu) |
| map[cpu] = cpu_to_queue_index(qmap, nr_queues, cpu); |
| else |
| map[cpu] = map[first_sibling]; |
| } |
| } |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_map_queues); |
| |
| /** |
| * blk_mq_hw_queue_to_node - Look up the memory node for a hardware queue index |
| * @qmap: CPU to hardware queue map. |
| * @index: hardware queue index. |
| * |
| * We have no quick way of doing reverse lookups. This is only used at |
| * queue init time, so runtime isn't important. |
| */ |
| int blk_mq_hw_queue_to_node(struct blk_mq_queue_map *qmap, unsigned int index) |
| { |
| int i; |
| |
| for_each_possible_cpu(i) { |
| if (index == qmap->mq_map[i]) |
| return local_memory_node(cpu_to_node(i)); |
| } |
| |
| return NUMA_NO_NODE; |
| } |