cregit-Linux how code gets into the kernel

Release 4.12 block/blk-mq-cpumap.c

Directory: block
 * 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(unsigned int nr_cpus, unsigned int nr_queues, const int cpu) { return cpu * nr_queues / nr_cpus; }


Jens Axboe2392.00%150.00%
Bart Van Assche28.00%150.00%

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; }


Jens Axboe3597.22%150.00%
Bartosz Golaszewski12.78%150.00%

int blk_mq_map_queues(struct blk_mq_tag_set *set) { unsigned int *map = set->mq_map; unsigned int nr_queues = set->nr_hw_queues; const struct cpumask *online_mask = cpu_online_mask; unsigned int i, nr_cpus, nr_uniq_cpus, queue, first_sibling; cpumask_var_t cpus; if (!alloc_cpumask_var(&cpus, GFP_ATOMIC)) return -ENOMEM; cpumask_clear(cpus); nr_cpus = nr_uniq_cpus = 0; for_each_cpu(i, online_mask) { nr_cpus++; first_sibling = get_first_sibling(i); if (!cpumask_test_cpu(first_sibling, cpus)) nr_uniq_cpus++; cpumask_set_cpu(i, cpus); } queue = 0; for_each_possible_cpu(i) { if (!cpumask_test_cpu(i, online_mask)) { map[i] = 0; continue; } /* * Easy case - we have equal or more hardware queues. Or * there are no thread siblings to take into account. Do * 1:1 if enough, or sequential mapping if less. */ if (nr_queues >= nr_cpus || nr_cpus == nr_uniq_cpus) { map[i] = cpu_to_queue_index(nr_cpus, nr_queues, queue); queue++; continue; } /* * Less then nr_cpus queues, and we have some number of * threads per cores. Map sibling threads to the same * queue. */ first_sibling = get_first_sibling(i); if (first_sibling == i) { map[i] = cpu_to_queue_index(nr_uniq_cpus, nr_queues, queue); queue++; } else map[i] = map[first_sibling]; } free_cpumask_var(cpus); return 0; }


Jens Axboe19485.46%133.33%
Christoph Hellwig229.69%133.33%
Akinobu Mita114.85%133.33%

EXPORT_SYMBOL_GPL(blk_mq_map_queues); /* * 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(unsigned int *mq_map, unsigned int index) { int i; for_each_possible_cpu(i) { if (index == mq_map[i]) return local_memory_node(cpu_to_node(i)); } return NUMA_NO_NODE; }


Jens Axboe4193.18%150.00%
Raghavendra K T36.82%150.00%

Overall Contributors

Jens Axboe32287.98%333.33%
Christoph Hellwig277.38%222.22%
Akinobu Mita113.01%111.11%
Raghavendra K T30.82%111.11%
Bart Van Assche20.55%111.11%
Bartosz Golaszewski10.27%111.11%
Directory: block
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