Git Repo - linux.git/blame_incremental

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Commit	Line	Data
	1	/*
	2	* CPU <-> hardware queue mapping helpers
	3	*
	4	* Copyright (C) 2013-2014 Jens Axboe
	5	*/
	6	#include <linux/kernel.h>
	7	#include <linux/threads.h>
	8	#include <linux/module.h>
	9	#include <linux/mm.h>
	10	#include <linux/smp.h>
	11	#include <linux/cpu.h>
	12
	13	#include <linux/blk-mq.h>
	14	#include "blk.h"
	15	#include "blk-mq.h"
	16
	17	static int cpu_to_queue_index(struct blk_mq_queue_map *qmap,
	18	unsigned int nr_queues, const int cpu)
	19	{
	20	return qmap->queue_offset + (cpu % nr_queues);
	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	}
	33
	34	int blk_mq_map_queues(struct blk_mq_queue_map *qmap)
	35	{
	36	unsigned int *map = qmap->mq_map;
	37	unsigned int nr_queues = qmap->nr_queues;
	38	unsigned int cpu, first_sibling;
	39
	40	for_each_possible_cpu(cpu) {
	41	/*
	42	* First do sequential mapping between CPUs and queues.
	43	* In case we still have CPUs to map, and we have some number of
	44	* threads per cores then map sibling threads to the same queue for
	45	* performace optimizations.
	46	*/
	47	if (cpu < nr_queues) {
	48	map[cpu] = cpu_to_queue_index(qmap, nr_queues, cpu);
	49	} else {
	50	first_sibling = get_first_sibling(cpu);
	51	if (first_sibling == cpu)
	52	map[cpu] = cpu_to_queue_index(qmap, nr_queues, cpu);
	53	else
	54	map[cpu] = map[first_sibling];
	55	}
	56	}
	57
	58	return 0;
	59	}
	60	EXPORT_SYMBOL_GPL(blk_mq_map_queues);
	61
	62	/*
	63	* We have no quick way of doing reverse lookups. This is only used at
	64	* queue init time, so runtime isn't important.
	65	*/
	66	int blk_mq_hw_queue_to_node(struct blk_mq_queue_map *qmap, unsigned int index)
	67	{
	68	int i;
	69
	70	for_each_possible_cpu(i) {
	71	if (index == qmap->mq_map[i])
	72	return local_memory_node(cpu_to_node(i));
	73	}
	74
	75	return NUMA_NO_NODE;
	76	}