]>
git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - block/blk-mq-cpumap.c
2 * CPU <-> hardware queue mapping helpers
4 * Copyright (C) 2013-2014 Jens Axboe
6 #include <linux/kernel.h>
7 #include <linux/threads.h>
8 #include <linux/module.h>
10 #include <linux/smp.h>
11 #include <linux/cpu.h>
13 #include <linux/blk-mq.h>
17 static int cpu_to_queue_index(unsigned int nr_cpus
, unsigned int nr_queues
,
20 return cpu
* nr_queues
/ nr_cpus
;
23 static int get_first_sibling(unsigned int cpu
)
27 ret
= cpumask_first(topology_sibling_cpumask(cpu
));
34 int blk_mq_update_queue_map(unsigned int *map
, unsigned int nr_queues
,
35 const struct cpumask
*online_mask
)
37 unsigned int i
, nr_cpus
, nr_uniq_cpus
, queue
, first_sibling
;
40 if (!alloc_cpumask_var(&cpus
, GFP_ATOMIC
))
44 nr_cpus
= nr_uniq_cpus
= 0;
45 for_each_cpu(i
, online_mask
) {
47 first_sibling
= get_first_sibling(i
);
48 if (!cpumask_test_cpu(first_sibling
, cpus
))
50 cpumask_set_cpu(i
, cpus
);
54 for_each_possible_cpu(i
) {
55 if (!cpumask_test_cpu(i
, online_mask
)) {
61 * Easy case - we have equal or more hardware queues. Or
62 * there are no thread siblings to take into account. Do
63 * 1:1 if enough, or sequential mapping if less.
65 if (nr_queues
>= nr_cpus
|| nr_cpus
== nr_uniq_cpus
) {
66 map
[i
] = cpu_to_queue_index(nr_cpus
, nr_queues
, queue
);
72 * Less then nr_cpus queues, and we have some number of
73 * threads per cores. Map sibling threads to the same
76 first_sibling
= get_first_sibling(i
);
77 if (first_sibling
== i
) {
78 map
[i
] = cpu_to_queue_index(nr_uniq_cpus
, nr_queues
,
82 map
[i
] = map
[first_sibling
];
85 free_cpumask_var(cpus
);
89 unsigned int *blk_mq_make_queue_map(struct blk_mq_tag_set
*set
)
93 /* If cpus are offline, map them to first hctx */
94 map
= kzalloc_node(sizeof(*map
) * nr_cpu_ids
, GFP_KERNEL
,
99 if (!blk_mq_update_queue_map(map
, set
->nr_hw_queues
, cpu_online_mask
))
107 * We have no quick way of doing reverse lookups. This is only used at
108 * queue init time, so runtime isn't important.
110 int blk_mq_hw_queue_to_node(unsigned int *mq_map
, unsigned int index
)
114 for_each_possible_cpu(i
) {
115 if (index
== mq_map
[i
])
116 return local_memory_node(cpu_to_node(i
));