Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid
[platform/kernel/linux-starfive.git] / block / blk-mq-cpumap.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * CPU <-> hardware queue mapping helpers
4  *
5  * Copyright (C) 2013-2014 Jens Axboe
6  */
7 #include <linux/kernel.h>
8 #include <linux/threads.h>
9 #include <linux/module.h>
10 #include <linux/mm.h>
11 #include <linux/smp.h>
12 #include <linux/cpu.h>
13
14 #include <linux/blk-mq.h>
15 #include "blk.h"
16 #include "blk-mq.h"
17
18 static int queue_index(struct blk_mq_queue_map *qmap,
19                        unsigned int nr_queues, const int q)
20 {
21         return qmap->queue_offset + (q % nr_queues);
22 }
23
24 static int get_first_sibling(unsigned int cpu)
25 {
26         unsigned int ret;
27
28         ret = cpumask_first(topology_sibling_cpumask(cpu));
29         if (ret < nr_cpu_ids)
30                 return ret;
31
32         return cpu;
33 }
34
35 int blk_mq_map_queues(struct blk_mq_queue_map *qmap)
36 {
37         unsigned int *map = qmap->mq_map;
38         unsigned int nr_queues = qmap->nr_queues;
39         unsigned int cpu, first_sibling, q = 0;
40
41         for_each_possible_cpu(cpu)
42                 map[cpu] = -1;
43
44         /*
45          * Spread queues among present CPUs first for minimizing
46          * count of dead queues which are mapped by all un-present CPUs
47          */
48         for_each_present_cpu(cpu) {
49                 if (q >= nr_queues)
50                         break;
51                 map[cpu] = queue_index(qmap, nr_queues, q++);
52         }
53
54         for_each_possible_cpu(cpu) {
55                 if (map[cpu] != -1)
56                         continue;
57                 /*
58                  * First do sequential mapping between CPUs and queues.
59                  * In case we still have CPUs to map, and we have some number of
60                  * threads per cores then map sibling threads to the same queue
61                  * for performance optimizations.
62                  */
63                 if (q < nr_queues) {
64                         map[cpu] = queue_index(qmap, nr_queues, q++);
65                 } else {
66                         first_sibling = get_first_sibling(cpu);
67                         if (first_sibling == cpu)
68                                 map[cpu] = queue_index(qmap, nr_queues, q++);
69                         else
70                                 map[cpu] = map[first_sibling];
71                 }
72         }
73
74         return 0;
75 }
76 EXPORT_SYMBOL_GPL(blk_mq_map_queues);
77
78 /**
79  * blk_mq_hw_queue_to_node - Look up the memory node for a hardware queue index
80  * @qmap: CPU to hardware queue map.
81  * @index: hardware queue index.
82  *
83  * We have no quick way of doing reverse lookups. This is only used at
84  * queue init time, so runtime isn't important.
85  */
86 int blk_mq_hw_queue_to_node(struct blk_mq_queue_map *qmap, unsigned int index)
87 {
88         int i;
89
90         for_each_possible_cpu(i) {
91                 if (index == qmap->mq_map[i])
92                         return cpu_to_node(i);
93         }
94
95         return NUMA_NO_NODE;
96 }