kernel-ark/block/blk-mq-cpumap.c
Jens Axboe 843477d4cc blk-mq: initial support for multiple queue maps
Add a queue offset to the tag map. This enables users to map
iteratively, for each queue map type they support.

Bump maximum number of supported maps to 2, we're now fully
able to support more than 1 map.

Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07 13:45:00 -07:00

77 lines
1.7 KiB
C

/*
* 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(struct blk_mq_queue_map *qmap,
unsigned int nr_queues, const int cpu)
{
return qmap->queue_offset + (cpu % nr_queues);
}
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;
}
int blk_mq_map_queues(struct blk_mq_queue_map *qmap)
{
unsigned int *map = qmap->mq_map;
unsigned int nr_queues = qmap->nr_queues;
unsigned int cpu, first_sibling;
for_each_possible_cpu(cpu) {
/*
* First do sequential mapping between CPUs and queues.
* In case we still have CPUs to map, and we have some number of
* threads per cores then map sibling threads to the same queue for
* performace optimizations.
*/
if (cpu < nr_queues) {
map[cpu] = cpu_to_queue_index(qmap, nr_queues, cpu);
} else {
first_sibling = get_first_sibling(cpu);
if (first_sibling == cpu)
map[cpu] = cpu_to_queue_index(qmap, nr_queues, cpu);
else
map[cpu] = map[first_sibling];
}
}
return 0;
}
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(struct blk_mq_queue_map *qmap, unsigned int index)
{
int i;
for_each_possible_cpu(i) {
if (index == qmap->mq_map[i])
return local_memory_node(cpu_to_node(i));
}
return NUMA_NO_NODE;
}