@@ -221,19 +221,71 @@ bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio,
}
EXPORT_SYMBOL_GPL(blk_mq_sched_try_merge);
+/*
+ * Reverse check our software queue for entries that we could potentially
+ * merge with. Currently includes a hand-wavy stop count of 8, to not spend
+ * too much time checking for merges.
+ */
+static bool blk_mq_attempt_merge(struct request_queue *q,
+ struct blk_mq_ctx *ctx, struct bio *bio)
+{
+ struct request *rq;
+ int checked = 8;
+
+ list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) {
+ bool merged = false;
+
+ if (!checked--)
+ break;
+
+ if (!blk_rq_merge_ok(rq, bio))
+ continue;
+
+ switch (blk_try_merge(rq, bio)) {
+ case ELEVATOR_BACK_MERGE:
+ if (blk_mq_sched_allow_merge(q, rq, bio))
+ merged = bio_attempt_back_merge(q, rq, bio);
+ break;
+ case ELEVATOR_FRONT_MERGE:
+ if (blk_mq_sched_allow_merge(q, rq, bio))
+ merged = bio_attempt_front_merge(q, rq, bio);
+ break;
+ case ELEVATOR_DISCARD_MERGE:
+ merged = bio_attempt_discard_merge(q, rq, bio);
+ break;
+ default:
+ continue;
+ }
+
+ if (merged)
+ ctx->rq_merged++;
+ return merged;
+ }
+
+ return false;
+}
+
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, ctx->cpu);
+ bool ret = false;
- if (e->type->ops.mq.bio_merge) {
- struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
- struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
-
+ if (e && e->type->ops.mq.bio_merge) {
blk_mq_put_ctx(ctx);
return e->type->ops.mq.bio_merge(hctx, bio);
}
- return false;
+ if (hctx->flags & BLK_MQ_F_SHOULD_MERGE) {
+ /* default per sw-queue merge */
+ spin_lock(&ctx->lock);
+ ret = blk_mq_attempt_merge(q, ctx, bio);
+ spin_unlock(&ctx->lock);
+ }
+
+ blk_mq_put_ctx(ctx);
+ return ret;
}
bool blk_mq_sched_try_insert_merge(struct request_queue *q, struct request *rq)
@@ -38,9 +38,7 @@ int blk_mq_sched_init(struct request_queue *q);
static inline bool
blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio)
{
- struct elevator_queue *e = q->elevator;
-
- if (!e || blk_queue_nomerges(q) || !bio_mergeable(bio))
+ if (blk_queue_nomerges(q) || !bio_mergeable(bio))
return false;
return __blk_mq_sched_bio_merge(q, bio);
@@ -772,50 +772,6 @@ static void blk_mq_timeout_work(struct work_struct *work)
blk_queue_exit(q);
}
-/*
- * Reverse check our software queue for entries that we could potentially
- * merge with. Currently includes a hand-wavy stop count of 8, to not spend
- * too much time checking for merges.
- */
-static bool blk_mq_attempt_merge(struct request_queue *q,
- struct blk_mq_ctx *ctx, struct bio *bio)
-{
- struct request *rq;
- int checked = 8;
-
- list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) {
- bool merged = false;
-
- if (!checked--)
- break;
-
- if (!blk_rq_merge_ok(rq, bio))
- continue;
-
- switch (blk_try_merge(rq, bio)) {
- case ELEVATOR_BACK_MERGE:
- if (blk_mq_sched_allow_merge(q, rq, bio))
- merged = bio_attempt_back_merge(q, rq, bio);
- break;
- case ELEVATOR_FRONT_MERGE:
- if (blk_mq_sched_allow_merge(q, rq, bio))
- merged = bio_attempt_front_merge(q, rq, bio);
- break;
- case ELEVATOR_DISCARD_MERGE:
- merged = bio_attempt_discard_merge(q, rq, bio);
- break;
- default:
- continue;
- }
-
- if (merged)
- ctx->rq_merged++;
- return merged;
- }
-
- return false;
-}
-
struct flush_busy_ctx_data {
struct blk_mq_hw_ctx *hctx;
struct list_head *list;
@@ -1446,23 +1402,6 @@ static inline bool hctx_allow_merges(struct blk_mq_hw_ctx *hctx)
!blk_queue_nomerges(hctx->queue);
}
-/* attempt to merge bio into current sw queue */
-static inline bool blk_mq_merge_bio(struct request_queue *q, struct bio *bio)
-{
- bool ret = false;
- struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
- struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
-
- if (hctx_allow_merges(hctx) && bio_mergeable(bio)) {
- spin_lock(&ctx->lock);
- ret = blk_mq_attempt_merge(q, ctx, bio);
- spin_unlock(&ctx->lock);
- }
-
- blk_mq_put_ctx(ctx);
- return ret;
-}
-
static inline void blk_mq_queue_io(struct blk_mq_hw_ctx *hctx,
struct blk_mq_ctx *ctx,
struct request *rq)
@@ -1568,9 +1507,6 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
if (blk_mq_sched_bio_merge(q, bio))
return BLK_QC_T_NONE;
- if (blk_mq_merge_bio(q, bio))
- return BLK_QC_T_NONE;
-
wb_acct = wbt_wait(q->rq_wb, bio, NULL);
trace_block_getrq(q, bio, bio->bi_opf);
Because what the per-sw-queue bio merge does is basically same with scheduler's .bio_merge(), this patch makes per-sw-queue bio merge as the default .bio_merge if no scheduler is used or io scheduler doesn't provide .bio_merge(). Signed-off-by: Ming Lei <ming.lei@redhat.com> --- Hi Christoph, Given blk_mq_attempt_merge() is only called in __blk_mq_sched_bio_merge(), and it isn't good to move __blk_mq_sched_bio_merge() into blk-mq.c because of the stuff of 'e && e->type->ops.mq.bio_merge' in this function, I keep this patch as before. Thanks, block/blk-mq-sched.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++---- block/blk-mq-sched.h | 4 +--- block/blk-mq.c | 64 ---------------------------------------------------- 3 files changed, 58 insertions(+), 72 deletions(-)