1 // SPDX-License-Identifier: GPL-2.0 <<
2 /* 1 /*
3 * CPU <-> hardware queue mapping helpers 2 * CPU <-> hardware queue mapping helpers
4 * 3 *
5 * Copyright (C) 2013-2014 Jens Axboe 4 * Copyright (C) 2013-2014 Jens Axboe
6 */ 5 */
7 #include <linux/kernel.h> 6 #include <linux/kernel.h>
8 #include <linux/threads.h> 7 #include <linux/threads.h>
9 #include <linux/module.h> 8 #include <linux/module.h>
10 #include <linux/mm.h> 9 #include <linux/mm.h>
11 #include <linux/smp.h> 10 #include <linux/smp.h>
12 #include <linux/cpu.h> 11 #include <linux/cpu.h>
13 #include <linux/group_cpus.h> <<
14 12
>> 13 #include <linux/blk-mq.h>
15 #include "blk.h" 14 #include "blk.h"
16 #include "blk-mq.h" 15 #include "blk-mq.h"
17 16
18 void blk_mq_map_queues(struct blk_mq_queue_map !! 17 static int cpu_to_queue_index(unsigned int nr_cpus, unsigned int nr_queues,
>> 18 const int cpu)
19 { 19 {
20 const struct cpumask *masks; !! 20 return cpu * nr_queues / nr_cpus;
21 unsigned int queue, cpu; !! 21 }
>> 22
>> 23 static int get_first_sibling(unsigned int cpu)
>> 24 {
>> 25 unsigned int ret;
>> 26
>> 27 ret = cpumask_first(topology_sibling_cpumask(cpu));
>> 28 if (ret < nr_cpu_ids)
>> 29 return ret;
>> 30
>> 31 return cpu;
>> 32 }
22 33
23 masks = group_cpus_evenly(qmap->nr_que !! 34 int blk_mq_map_queues(struct blk_mq_tag_set *set)
24 if (!masks) { !! 35 {
25 for_each_possible_cpu(cpu) !! 36 unsigned int *map = set->mq_map;
26 qmap->mq_map[cpu] = qm !! 37 unsigned int nr_queues = set->nr_hw_queues;
27 return; !! 38 const struct cpumask *online_mask = cpu_online_mask;
>> 39 unsigned int i, nr_cpus, nr_uniq_cpus, queue, first_sibling;
>> 40 cpumask_var_t cpus;
>> 41
>> 42 if (!alloc_cpumask_var(&cpus, GFP_ATOMIC))
>> 43 return -ENOMEM;
>> 44
>> 45 cpumask_clear(cpus);
>> 46 nr_cpus = nr_uniq_cpus = 0;
>> 47 for_each_cpu(i, online_mask) {
>> 48 nr_cpus++;
>> 49 first_sibling = get_first_sibling(i);
>> 50 if (!cpumask_test_cpu(first_sibling, cpus))
>> 51 nr_uniq_cpus++;
>> 52 cpumask_set_cpu(i, cpus);
28 } 53 }
29 54
30 for (queue = 0; queue < qmap->nr_queue !! 55 queue = 0;
31 for_each_cpu(cpu, &masks[queue !! 56 for_each_possible_cpu(i) {
32 qmap->mq_map[cpu] = qm !! 57 if (!cpumask_test_cpu(i, online_mask)) {
>> 58 map[i] = 0;
>> 59 continue;
>> 60 }
>> 61
>> 62 /*
>> 63 * Easy case - we have equal or more hardware queues. Or
>> 64 * there are no thread siblings to take into account. Do
>> 65 * 1:1 if enough, or sequential mapping if less.
>> 66 */
>> 67 if (nr_queues >= nr_cpus || nr_cpus == nr_uniq_cpus) {
>> 68 map[i] = cpu_to_queue_index(nr_cpus, nr_queues, queue);
>> 69 queue++;
>> 70 continue;
>> 71 }
>> 72
>> 73 /*
>> 74 * Less then nr_cpus queues, and we have some number of
>> 75 * threads per cores. Map sibling threads to the same
>> 76 * queue.
>> 77 */
>> 78 first_sibling = get_first_sibling(i);
>> 79 if (first_sibling == i) {
>> 80 map[i] = cpu_to_queue_index(nr_uniq_cpus, nr_queues,
>> 81 queue);
>> 82 queue++;
>> 83 } else
>> 84 map[i] = map[first_sibling];
33 } 85 }
34 kfree(masks); !! 86
>> 87 free_cpumask_var(cpus);
>> 88 return 0;
35 } 89 }
36 EXPORT_SYMBOL_GPL(blk_mq_map_queues); 90 EXPORT_SYMBOL_GPL(blk_mq_map_queues);
37 91
38 /** !! 92 /*
39 * blk_mq_hw_queue_to_node - Look up the memor <<
40 * @qmap: CPU to hardware queue map. <<
41 * @index: hardware queue index. <<
42 * <<
43 * We have no quick way of doing reverse looku 93 * We have no quick way of doing reverse lookups. This is only used at
44 * queue init time, so runtime isn't important 94 * queue init time, so runtime isn't important.
45 */ 95 */
46 int blk_mq_hw_queue_to_node(struct blk_mq_queu !! 96 int blk_mq_hw_queue_to_node(unsigned int *mq_map, unsigned int index)
47 { 97 {
48 int i; 98 int i;
49 99
50 for_each_possible_cpu(i) { 100 for_each_possible_cpu(i) {
51 if (index == qmap->mq_map[i]) !! 101 if (index == mq_map[i])
52 return cpu_to_node(i); !! 102 return local_memory_node(cpu_to_node(i));
53 } 103 }
54 104
55 return NUMA_NO_NODE; 105 return NUMA_NO_NODE;
56 } 106 }
57 107
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.