blk-mq: save queue mapping result into ctx directly

Currently, the queue mapping result is saved in a two-dimensional
array. In the hot path, to get a hctx, we need do following:

  q->queue_hw_ctx[q->tag_set->map[type].mq_map[cpu]]

This isn't very efficient. We could save the queue mapping result into
ctx directly with different hctx type, like,

  ctx->hctxs[type]

Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jianchao Wang 2019-01-24 18:25:32 +08:00 committed by Jens Axboe
parent 058fdecc6d
commit 8ccdf4a377
5 changed files with 9 additions and 8 deletions

View File

@ -321,7 +321,7 @@ bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio)
{
struct elevator_queue *e = q->elevator;
struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, bio->bi_opf, ctx->cpu);
struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, bio->bi_opf, ctx);
bool ret = false;
enum hctx_type type;

View File

@ -170,7 +170,7 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
data->ctx = blk_mq_get_ctx(data->q);
data->hctx = blk_mq_map_queue(data->q, data->cmd_flags,
data->ctx->cpu);
data->ctx);
tags = blk_mq_tags_from_data(data);
if (data->flags & BLK_MQ_REQ_RESERVED)
bt = &tags->breserved_tags;

View File

@ -364,7 +364,7 @@ static struct request *blk_mq_get_request(struct request_queue *q,
}
if (likely(!data->hctx))
data->hctx = blk_mq_map_queue(q, data->cmd_flags,
data->ctx->cpu);
data->ctx);
if (data->cmd_flags & REQ_NOWAIT)
data->flags |= BLK_MQ_REQ_NOWAIT;
@ -2435,7 +2435,7 @@ static void blk_mq_map_swqueue(struct request_queue *q)
continue;
hctx = blk_mq_map_queue_type(q, j, i);
ctx->hctxs[j] = hctx;
/*
* If the CPU is already set in the mask, then we've
* mapped this one already. This can happen if

View File

@ -23,6 +23,7 @@ struct blk_mq_ctx {
unsigned int cpu;
unsigned short index_hw[HCTX_MAX_TYPES];
struct blk_mq_hw_ctx *hctxs[HCTX_MAX_TYPES];
/* incremented at dispatch time */
unsigned long rq_dispatched[2];
@ -97,11 +98,11 @@ static inline struct blk_mq_hw_ctx *blk_mq_map_queue_type(struct request_queue *
* blk_mq_map_queue() - map (cmd_flags,type) to hardware queue
* @q: request queue
* @flags: request command flags
* @cpu: CPU
* @cpu: cpu ctx
*/
static inline struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q,
unsigned int flags,
unsigned int cpu)
struct blk_mq_ctx *ctx)
{
enum hctx_type type = HCTX_TYPE_DEFAULT;
@ -116,7 +117,7 @@ static inline struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q,
q->tag_set->map[HCTX_TYPE_READ].nr_queues)
type = HCTX_TYPE_READ;
return blk_mq_map_queue_type(q, type, cpu);
return ctx->hctxs[type];
}
/*

View File

@ -38,7 +38,7 @@ extern struct ida blk_queue_ida;
static inline struct blk_flush_queue *
blk_get_flush_queue(struct request_queue *q, struct blk_mq_ctx *ctx)
{
return blk_mq_map_queue(q, REQ_OP_FLUSH, ctx->cpu)->fq;
return blk_mq_map_queue(q, REQ_OP_FLUSH, ctx)->fq;
}
static inline void __blk_get_queue(struct request_queue *q)