From: Liu Song <liusong@xxxxxxxxxxxxxxxxx>
Some conditions for judging whether batch alloc can be performed are
included in "blk_mq_get_tags", and this function is only used by
"__blk_mq_alloc_requests_batch".
This patch introduced a helper "can_do_batch_alloc" to prepend the
judgment condition and avoid unnecessary function calls.
Signed-off-by: Liu Song <liusong@xxxxxxxxxxxxxxxxx>
---
block/blk-mq-tag.c | 3 ---
block/blk-mq.c | 11 ++++++++++-
2 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 8e3b36d..cda3987 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -115,9 +115,6 @@ unsigned long blk_mq_get_tags(struct blk_mq_alloc_data *data, int nr_tags,
struct sbitmap_queue *bt = &tags->bitmap_tags;
unsigned long ret;
- if (data->shallow_depth ||data->flags & BLK_MQ_REQ_RESERVED ||
- data->hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)
- return 0;
ret = __sbitmap_queue_get_batch(bt, nr_tags, offset);
*offset += tags->nr_reserved_tags;
return ret;
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 3c1e6b6..330c618 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -437,6 +437,15 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
return rq_list_pop(data->cached_rq);
}
+static inline bool can_do_batch_alloc(struct blk_mq_alloc_data *data)
+{
+ if (data->nr_tags > 1 && !(data->shallow_depth ||
+ data->flags & BLK_MQ_REQ_RESERVED ||
+ data->hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED))
+ return true;
+ return false;
+}
+
static struct request *__blk_mq_alloc_requests(struct blk_mq_alloc_data *data)
{
struct request_queue *q = data->q;
@@ -480,7 +489,7 @@ static struct request *__blk_mq_alloc_requests(struct blk_mq_alloc_data *data)
/*
* Try batched alloc if we want more than 1 tag.
*/
- if (data->nr_tags > 1) {
+ if (can_do_batch_alloc(data)) {
rq = __blk_mq_alloc_requests_batch(data, alloc_time_ns);
if (rq)
return rq;
--
1.8.3.1
