LXR linux/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#include <linux/group_cpus.h>
  14
  15#include "blk.h"
  16#include "blk-mq.h"
  17
  18void blk_mq_map_queues(struct blk_mq_queue_map *qmap)
  19{
  20        const struct cpumask *masks;
  21        unsigned int queue, cpu;
  22
  23        masks = group_cpus_evenly(qmap->nr_queues);
  24        if (!masks) {
  25                for_each_possible_cpu(cpu)
  26                        qmap->mq_map[cpu] = qmap->queue_offset;
  27                return;
  28        }
  29
  30        for (queue = 0; queue < qmap->nr_queues; queue++) {
  31                for_each_cpu(cpu, &masks[queue])
  32                        qmap->mq_map[cpu] = qmap->queue_offset + queue;
  33        }
  34        kfree(masks);
  35}
  36EXPORT_SYMBOL_GPL(blk_mq_map_queues);
  37
  38/**
  39 * blk_mq_hw_queue_to_node - Look up the memory node for a hardware queue index
  40 * @qmap: CPU to hardware queue map.
  41 * @index: hardware queue index.
  42 *
  43 * We have no quick way of doing reverse lookups. This is only used at
  44 * queue init time, so runtime isn't important.
  45 */
  46int blk_mq_hw_queue_to_node(struct blk_mq_queue_map *qmap, unsigned int index)
  47{
  48        int i;
  49
  50        for_each_possible_cpu(i) {
  51                if (index == qmap->mq_map[i])
  52                        return cpu_to_node(i);
  53        }
  54
  55        return NUMA_NO_NODE;
  56}
  57