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blk-mq: pass obtained budget count to blk_mq_dispatch_rq_list

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Pass obtained budget count to blk_mq_dispatch_rq_list(), and prepare
for supporting fully batching submission.

With the obtained budget count, it is easier to put extra budgets
in case of .queue_rq failure.

Meantime remove the old 'got_budget' parameter.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Baolin Wang <baolin.wang7@gmail.com>
Reviewed-by: Christoph Hellwig <hch@infradead.org>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Baolin Wang <baolin.wang7@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ming Lei 2020-06-30 18:25:00 +08:00 committed by Jens Axboe
parent bbdb3c5d94
commit 1fd40b5ea7
3 changed files with 33 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
block/blk-mq-sched.c
View File

@ -130,7 +130,7 @@ static int blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx)
* in blk_mq_dispatch_rq_list().
*/
list_add(&rq->queuelist, &rq_list);
} while (blk_mq_dispatch_rq_list(rq->mq_hctx, &rq_list, true));
} while (blk_mq_dispatch_rq_list(rq->mq_hctx, &rq_list, 1));
return ret;
}
@ -198,7 +198,7 @@ static int blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx)
/* round robin for fair dispatch */
ctx = blk_mq_next_ctx(hctx, rq->mq_ctx);
} while (blk_mq_dispatch_rq_list(rq->mq_hctx, &rq_list, true));
} while (blk_mq_dispatch_rq_list(rq->mq_hctx, &rq_list, 1));
WRITE_ONCE(hctx->dispatch_from, ctx);
return ret;
@ -238,7 +238,7 @@ static int __blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
*/
if (!list_empty(&rq_list)) {
blk_mq_sched_mark_restart_hctx(hctx);
if (blk_mq_dispatch_rq_list(hctx, &rq_list, false)) {
if (blk_mq_dispatch_rq_list(hctx, &rq_list, 0)) {
if (has_sched_dispatch)
ret = blk_mq_do_dispatch_sched(hctx);
else
@ -251,7 +251,7 @@ static int __blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
ret = blk_mq_do_dispatch_ctx(hctx);
} else {
blk_mq_flush_busy_ctxs(hctx, &rq_list);
blk_mq_dispatch_rq_list(hctx, &rq_list, false);
blk_mq_dispatch_rq_list(hctx, &rq_list, 0);
}
return ret;

29
block/blk-mq.c
View File

@ -1280,6 +1280,11 @@ static enum prep_dispatch blk_mq_prep_dispatch_rq(struct request *rq,
* we'll re-run it below.
*/
if (!blk_mq_mark_tag_wait(hctx, rq)) {
/*
* All budgets not got from this function will be put
* together during handling partial dispatch
*/
if (need_budget)
blk_mq_put_dispatch_budget(rq->q);
return PREP_DISPATCH_NO_TAG;
}
@ -1288,11 +1293,21 @@ static enum prep_dispatch blk_mq_prep_dispatch_rq(struct request *rq,
return PREP_DISPATCH_OK;
}
/* release all allocated budgets before calling to blk_mq_dispatch_rq_list */
static void blk_mq_release_budgets(struct request_queue *q,
unsigned int nr_budgets)
{
int i;
for (i = 0; i < nr_budgets; i++)
blk_mq_put_dispatch_budget(q);
}
/*
* Returns true if we did some work AND can potentially do more.
*/
bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
bool got_budget)
unsigned int nr_budgets)
{
enum prep_dispatch prep;
struct request_queue *q = hctx->queue;
@ -1304,7 +1319,7 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
if (list_empty(list))
return false;
WARN_ON(!list_is_singular(list) && got_budget);
WARN_ON(!list_is_singular(list) && nr_budgets);
/*
* Now process all the entries, sending them to the driver.
@ -1316,7 +1331,7 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
rq = list_first_entry(list, struct request, queuelist);
WARN_ON_ONCE(hctx != rq->mq_hctx);
prep = blk_mq_prep_dispatch_rq(rq, !got_budget);
prep = blk_mq_prep_dispatch_rq(rq, !nr_budgets);
if (prep != PREP_DISPATCH_OK)
break;
@ -1335,6 +1350,12 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
bd.last = !blk_mq_get_driver_tag(nxt);
}
/*
* once the request is queued to lld, no need to cover the
* budget any more
*/
if (nr_budgets)
nr_budgets--;
ret = q->mq_ops->queue_rq(hctx, &bd);
if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) {
blk_mq_handle_dev_resource(rq, list);
@ -1376,6 +1397,8 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
(hctx->flags & BLK_MQ_F_TAG_SHARED);
bool no_budget_avail = prep == PREP_DISPATCH_NO_BUDGET;
blk_mq_release_budgets(q, nr_budgets);
/*
* If we didn't flush the entire list, we could have told
* the driver there was more coming, but that turned out to

3
block/blk-mq.h
View File

@ -40,7 +40,8 @@ struct blk_mq_ctx {
void blk_mq_exit_queue(struct request_queue *q);
int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr);
void blk_mq_wake_waiters(struct request_queue *q);
bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *, bool);
bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *,
unsigned int);
void blk_mq_add_to_requeue_list(struct request *rq, bool at_head,
bool kick_requeue_list);
void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list);