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blk-mq: support multiple hctx maps

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Add support for the tag set carrying multiple queue maps, and
for the driver to inform blk-mq how many it wishes to support
through setting set->nr_maps.

This adds an mq_ops helper for drivers that support more than 1
map, mq_ops->rq_flags_to_type(). The function takes request/bio
flags and CPU, and returns a queue map index for that. We then
use the type information in blk_mq_map_queue() to index the map
set.

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>
This commit is contained in:
Jens Axboe 2018-10-30 10:36:06 -06:00
parent a783b81820
commit b3c661b15d
3 changed files with 102 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

92
block/blk-mq.c
View File

@ -2258,7 +2258,8 @@ static int blk_mq_init_hctx(struct request_queue *q,
static void blk_mq_init_cpu_queues(struct request_queue *q,
unsigned int nr_hw_queues)
{
unsigned int i;
struct blk_mq_tag_set *set = q->tag_set;
unsigned int i, j;
for_each_possible_cpu(i) {
struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i);
@ -2273,9 +2274,11 @@ static void blk_mq_init_cpu_queues(struct request_queue *q,
* Set local node, IFF we have more than one hw queue. If
* not, we remain on the home node of the device
*/
hctx = blk_mq_map_queue_type(q, 0, i);
if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE)
hctx->numa_node = local_memory_node(cpu_to_node(i));
for (j = 0; j < set->nr_maps; j++) {
hctx = blk_mq_map_queue_type(q, j, i);
if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE)
hctx->numa_node = local_memory_node(cpu_to_node(i));
}
}
}
@ -2310,7 +2313,7 @@ static void blk_mq_free_map_and_requests(struct blk_mq_tag_set *set,
static void blk_mq_map_swqueue(struct request_queue *q)
{
unsigned int i, hctx_idx;
unsigned int i, j, hctx_idx;
struct blk_mq_hw_ctx *hctx;
struct blk_mq_ctx *ctx;
struct blk_mq_tag_set *set = q->tag_set;
@ -2346,17 +2349,28 @@ static void blk_mq_map_swqueue(struct request_queue *q)
}
ctx = per_cpu_ptr(q->queue_ctx, i);
hctx = blk_mq_map_queue_type(q, 0, i);
hctx->type = 0;
cpumask_set_cpu(i, hctx->cpumask);
ctx->index_hw[hctx->type] = hctx->nr_ctx;
hctx->ctxs[hctx->nr_ctx++] = ctx;
for (j = 0; j < set->nr_maps; j++) {
hctx = blk_mq_map_queue_type(q, j, i);
/*
* If the nr_ctx type overflows, we have exceeded the
* amount of sw queues we can support.
*/
BUG_ON(!hctx->nr_ctx);
/*
* If the CPU is already set in the mask, then we've
* mapped this one already. This can happen if
* devices share queues across queue maps.
*/
if (cpumask_test_cpu(i, hctx->cpumask))
continue;
cpumask_set_cpu(i, hctx->cpumask);
hctx->type = j;
ctx->index_hw[hctx->type] = hctx->nr_ctx;
hctx->ctxs[hctx->nr_ctx++] = ctx;
/*
* If the nr_ctx type overflows, we have exceeded the
* amount of sw queues we can support.
*/
BUG_ON(!hctx->nr_ctx);
}
}
mutex_unlock(&q->sysfs_lock);
@ -2524,6 +2538,7 @@ struct request_queue *blk_mq_init_sq_queue(struct blk_mq_tag_set *set,
memset(set, 0, sizeof(*set));
set->ops = ops;
set->nr_hw_queues = 1;
set->nr_maps = 1;
set->queue_depth = queue_depth;
set->numa_node = NUMA_NO_NODE;
set->flags = set_flags;
@ -2800,6 +2815,8 @@ static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
static int blk_mq_update_queue_map(struct blk_mq_tag_set *set)
{
if (set->ops->map_queues) {
int i;
/*
* transport .map_queues is usually done in the following
* way:
@ -2807,18 +2824,21 @@ static int blk_mq_update_queue_map(struct blk_mq_tag_set *set)
* for (queue = 0; queue < set->nr_hw_queues; queue++) {
* mask = get_cpu_mask(queue)
* for_each_cpu(cpu, mask)
* set->map.mq_map[cpu] = queue;
* set->map[x].mq_map[cpu] = queue;
* }
*
* When we need to remap, the table has to be cleared for
* killing stale mapping since one CPU may not be mapped
* to any hw queue.
*/
blk_mq_clear_mq_map(&set->map[0]);
for (i = 0; i < set->nr_maps; i++)
blk_mq_clear_mq_map(&set->map[i]);
return set->ops->map_queues(set);
} else
} else {
BUG_ON(set->nr_maps > 1);
return blk_mq_map_queues(&set->map[0]);
}
}
/*
@ -2829,7 +2849,7 @@ static int blk_mq_update_queue_map(struct blk_mq_tag_set *set)
*/
int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
{
int ret;
int i, ret;
BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS);
@ -2852,6 +2872,11 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
set->queue_depth = BLK_MQ_MAX_DEPTH;
}
if (!set->nr_maps)
set->nr_maps = 1;
else if (set->nr_maps > HCTX_MAX_TYPES)
return -EINVAL;
/*
* If a crashdump is active, then we are potentially in a very
* memory constrained environment. Limit us to 1 queue and
@ -2873,12 +2898,14 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
return -ENOMEM;
ret = -ENOMEM;
set->map[0].mq_map = kcalloc_node(nr_cpu_ids,
sizeof(*set->map[0].mq_map),
GFP_KERNEL, set->numa_node);
if (!set->map[0].mq_map)
goto out_free_tags;
set->map[0].nr_queues = set->nr_hw_queues;
for (i = 0; i < set->nr_maps; i++) {
set->map[i].mq_map = kcalloc_node(nr_cpu_ids,
sizeof(struct blk_mq_queue_map),
GFP_KERNEL, set->numa_node);
if (!set->map[i].mq_map)
goto out_free_mq_map;
set->map[i].nr_queues = set->nr_hw_queues;
}
ret = blk_mq_update_queue_map(set);
if (ret)
@ -2894,9 +2921,10 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
return 0;
out_free_mq_map:
kfree(set->map[0].mq_map);
set->map[0].mq_map = NULL;
out_free_tags:
for (i = 0; i < set->nr_maps; i++) {
kfree(set->map[i].mq_map);
set->map[i].mq_map = NULL;
}
kfree(set->tags);
set->tags = NULL;
return ret;
@ -2905,13 +2933,15 @@ EXPORT_SYMBOL(blk_mq_alloc_tag_set);
void blk_mq_free_tag_set(struct blk_mq_tag_set *set)
{
int i;
int i, j;
for (i = 0; i < nr_cpu_ids; i++)
blk_mq_free_map_and_requests(set, i);
kfree(set->map[0].mq_map);
set->map[0].mq_map = NULL;
for (j = 0; j < set->nr_maps; j++) {
kfree(set->map[j].mq_map);
set->map[j].mq_map = NULL;
}
kfree(set->tags);
set->tags = NULL;

37
block/blk-mq.h
View File

@ -72,20 +72,37 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
*/
extern int blk_mq_hw_queue_to_node(struct blk_mq_queue_map *qmap, unsigned int);
static inline struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q,
unsigned int flags,
unsigned int cpu)
{
struct blk_mq_tag_set *set = q->tag_set;
return q->queue_hw_ctx[set->map[0].mq_map[cpu]];
}
/*
* blk_mq_map_queue_type() - map (hctx_type,cpu) to hardware queue
* @q: request queue
* @hctx_type: the hctx type index
* @cpu: CPU
*/
static inline struct blk_mq_hw_ctx *blk_mq_map_queue_type(struct request_queue *q,
unsigned int hctx_type,
unsigned int cpu)
{
return blk_mq_map_queue(q, hctx_type, cpu);
struct blk_mq_tag_set *set = q->tag_set;
return q->queue_hw_ctx[set->map[hctx_type].mq_map[cpu]];
}
/*
* blk_mq_map_queue() - map (cmd_flags,type) to hardware queue
* @q: request queue
* @flags: request command flags
* @cpu: CPU
*/
static inline struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q,
unsigned int flags,
unsigned int cpu)
{
int hctx_type = 0;
if (q->mq_ops->rq_flags_to_type)
hctx_type = q->mq_ops->rq_flags_to_type(q, flags);
return blk_mq_map_queue_type(q, hctx_type, cpu);
}
/*

14
include/linux/blk-mq.h
View File

@ -85,7 +85,14 @@ enum {
};
struct blk_mq_tag_set {
/*
* map[] holds ctx -> hctx mappings, one map exists for each type
* that the driver wishes to support. There are no restrictions
* on maps being of the same size, and it's perfectly legal to
* share maps between types.
*/
struct blk_mq_queue_map map[HCTX_MAX_TYPES];
unsigned int nr_maps; /* nr entries in map[] */
const struct blk_mq_ops *ops;
unsigned int nr_hw_queues; /* nr hw queues across maps */
unsigned int queue_depth; /* max hw supported */
@ -109,6 +116,8 @@ struct blk_mq_queue_data {
typedef blk_status_t (queue_rq_fn)(struct blk_mq_hw_ctx *,
const struct blk_mq_queue_data *);
/* takes rq->cmd_flags as input, returns a hardware type index */
typedef int (rq_flags_to_type_fn)(struct request_queue *, unsigned int);
typedef bool (get_budget_fn)(struct blk_mq_hw_ctx *);
typedef void (put_budget_fn)(struct blk_mq_hw_ctx *);
typedef enum blk_eh_timer_return (timeout_fn)(struct request *, bool);
@ -134,6 +143,11 @@ struct blk_mq_ops {
*/
queue_rq_fn *queue_rq;
/*
* Return a queue map type for the given request/bio flags
*/
rq_flags_to_type_fn *rq_flags_to_type;
/*
* Reserve budget before queue request, once .queue_rq is
* run, it is driver's responsibility to release the