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96 lines
2.2 KiB
96 lines
2.2 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* CPU <-> hardware queue mapping helpers |
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* |
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* Copyright (C) 2013-2014 Jens Axboe |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/threads.h> |
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#include <linux/module.h> |
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#include <linux/mm.h> |
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#include <linux/smp.h> |
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#include <linux/cpu.h> |
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#include <linux/blk-mq.h> |
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#include "blk.h" |
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#include "blk-mq.h" |
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static int queue_index(struct blk_mq_queue_map *qmap, |
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unsigned int nr_queues, const int q) |
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{ |
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return qmap->queue_offset + (q % nr_queues); |
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} |
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static int get_first_sibling(unsigned int cpu) |
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{ |
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unsigned int ret; |
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ret = cpumask_first(topology_sibling_cpumask(cpu)); |
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if (ret < nr_cpu_ids) |
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return ret; |
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return cpu; |
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} |
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int blk_mq_map_queues(struct blk_mq_queue_map *qmap) |
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{ |
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unsigned int *map = qmap->mq_map; |
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unsigned int nr_queues = qmap->nr_queues; |
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unsigned int cpu, first_sibling, q = 0; |
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for_each_possible_cpu(cpu) |
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map[cpu] = -1; |
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/* |
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* Spread queues among present CPUs first for minimizing |
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* count of dead queues which are mapped by all un-present CPUs |
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*/ |
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for_each_present_cpu(cpu) { |
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if (q >= nr_queues) |
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break; |
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map[cpu] = queue_index(qmap, nr_queues, q++); |
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} |
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for_each_possible_cpu(cpu) { |
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if (map[cpu] != -1) |
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continue; |
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/* |
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* First do sequential mapping between CPUs and queues. |
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* In case we still have CPUs to map, and we have some number of |
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* threads per cores then map sibling threads to the same queue |
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* for performance optimizations. |
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*/ |
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if (q < nr_queues) { |
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map[cpu] = queue_index(qmap, nr_queues, q++); |
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} else { |
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first_sibling = get_first_sibling(cpu); |
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if (first_sibling == cpu) |
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map[cpu] = queue_index(qmap, nr_queues, q++); |
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else |
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map[cpu] = map[first_sibling]; |
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} |
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} |
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return 0; |
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} |
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EXPORT_SYMBOL_GPL(blk_mq_map_queues); |
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/** |
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* blk_mq_hw_queue_to_node - Look up the memory node for a hardware queue index |
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* @qmap: CPU to hardware queue map. |
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* @index: hardware queue index. |
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* |
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* We have no quick way of doing reverse lookups. This is only used at |
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* queue init time, so runtime isn't important. |
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*/ |
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int blk_mq_hw_queue_to_node(struct blk_mq_queue_map *qmap, unsigned int index) |
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{ |
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int i; |
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for_each_possible_cpu(i) { |
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if (index == qmap->mq_map[i]) |
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return cpu_to_node(i); |
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} |
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return NUMA_NO_NODE; |
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}
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