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blk-mq: save default hctx into ctx->hctxs for not-supported type

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Currently, we check whether the hctx type is supported every time
in hot path. Actually, this is not necessary, we could save the
default hctx into ctx->hctxs if the type is not supported when
map swqueues and use it directly with ctx->hctxs[type].

We also needn't check whether the poll is enabled or not, because
the caller would clear the REQ_HIPRI in that case.

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 18:25:33 +08:00 committed by Jens Axboe
parent 8ccdf4a377
commit bb94aea144
2 changed files with 13 additions and 9 deletions
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9
block/blk-mq.c
View File

@ -2431,8 +2431,11 @@ static void blk_mq_map_swqueue(struct request_queue *q)
ctx = per_cpu_ptr(q->queue_ctx, i);
for (j = 0; j < set->nr_maps; j++) {
if (!set->map[j].nr_queues)
if (!set->map[j].nr_queues) {
ctx->hctxs[j] = blk_mq_map_queue_type(q,
HCTX_TYPE_DEFAULT, i);
continue;
}
hctx = blk_mq_map_queue_type(q, j, i);
ctx->hctxs[j] = hctx;
@ -2455,6 +2458,10 @@ static void blk_mq_map_swqueue(struct request_queue *q)
*/
BUG_ON(!hctx->nr_ctx);
}
for (; j < HCTX_MAX_TYPES; j++)
ctx->hctxs[j] = blk_mq_map_queue_type(q,
HCTX_TYPE_DEFAULT, i);
}
mutex_unlock(&q->sysfs_lock);

13
block/blk-mq.h
View File

@ -106,15 +106,12 @@ static inline struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q,
{
enum hctx_type type = HCTX_TYPE_DEFAULT;
if ((flags & REQ_HIPRI) &&
q->tag_set->nr_maps > HCTX_TYPE_POLL &&
q->tag_set->map[HCTX_TYPE_POLL].nr_queues &&
test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
/*
* The caller ensure that if REQ_HIPRI, poll must be enabled.
*/
if (flags & REQ_HIPRI)
type = HCTX_TYPE_POLL;
else if (((flags & REQ_OP_MASK) == REQ_OP_READ) &&
q->tag_set->nr_maps > HCTX_TYPE_READ &&
q->tag_set->map[HCTX_TYPE_READ].nr_queues)
else if ((flags & REQ_OP_MASK) == REQ_OP_READ)
type = HCTX_TYPE_READ;
return ctx->hctxs[type];