From: Ming Lei <ming.lei@redhat.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, Ming Lei <ming.lei@redhat.com>,
Sagi Grimberg <sagi@grimberg.me>,
Baolin Wang <baolin.wang7@gmail.com>,
Christoph Hellwig <hch@infradead.org>,
Johannes Thumshirn <johannes.thumshirn@wdc.com>
Subject: [PATCH V6 3/6] blk-mq: move getting driver tag and budget into one helper
Date: Thu, 25 Jun 2020 07:03:46 +0800 [thread overview]
Message-ID: <20200624230349.1046821-4-ming.lei@redhat.com> (raw)
In-Reply-To: <20200624230349.1046821-1-ming.lei@redhat.com>
Move code for getting driver tag and budget into one helper, so
blk_mq_dispatch_rq_list gets a bit simplified, and easier to read.
Meantime move updating of 'no_tag' and 'no_budget_available' into
the branch for handling partial dispatch because that is exactly
consumer of the two local variables.
Also rename the parameter of 'got_budget' as 'ask_budget'.
No functional change.
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Baolin Wang <baolin.wang7@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Tested-by: Baolin Wang <baolin.wang7@gmail.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
block/blk-mq.c | 66 ++++++++++++++++++++++++++++++--------------------
1 file changed, 40 insertions(+), 26 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 481bd8973c93..f58d46409de4 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1257,18 +1257,50 @@ static void blk_mq_handle_zone_resource(struct request *rq,
__blk_mq_requeue_request(rq);
}
+enum prep_dispatch {
+ PREP_DISPATCH_OK,
+ PREP_DISPATCH_NO_TAG,
+ PREP_DISPATCH_NO_BUDGET,
+};
+
+static enum prep_dispatch blk_mq_prep_dispatch_rq(struct request *rq,
+ bool need_budget)
+{
+ struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
+
+ if (need_budget && !blk_mq_get_dispatch_budget(rq->q)) {
+ blk_mq_put_driver_tag(rq);
+ return PREP_DISPATCH_NO_BUDGET;
+ }
+
+ if (!blk_mq_get_driver_tag(rq)) {
+ /*
+ * The initial allocation attempt failed, so we need to
+ * rerun the hardware queue when a tag is freed. The
+ * waitqueue takes care of that. If the queue is run
+ * before we add this entry back on the dispatch list,
+ * we'll re-run it below.
+ */
+ if (!blk_mq_mark_tag_wait(hctx, rq)) {
+ blk_mq_put_dispatch_budget(rq->q);
+ return PREP_DISPATCH_NO_TAG;
+ }
+ }
+
+ return PREP_DISPATCH_OK;
+}
+
/*
* 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)
{
+ enum prep_dispatch prep;
struct request_queue *q = hctx->queue;
struct request *rq, *nxt;
- bool no_tag = false;
int errors, queued;
blk_status_t ret = BLK_STS_OK;
- bool no_budget_avail = false;
LIST_HEAD(zone_list);
if (list_empty(list))
@@ -1286,31 +1318,9 @@ 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);
- if (!got_budget && !blk_mq_get_dispatch_budget(q)) {
- blk_mq_put_driver_tag(rq);
- no_budget_avail = true;
+ prep = blk_mq_prep_dispatch_rq(rq, !got_budget);
+ if (prep != PREP_DISPATCH_OK)
break;
- }
-
- if (!blk_mq_get_driver_tag(rq)) {
- /*
- * The initial allocation attempt failed, so we need to
- * rerun the hardware queue when a tag is freed. The
- * waitqueue takes care of that. If the queue is run
- * before we add this entry back on the dispatch list,
- * we'll re-run it below.
- */
- if (!blk_mq_mark_tag_wait(hctx, rq)) {
- blk_mq_put_dispatch_budget(q);
- /*
- * For non-shared tags, the RESTART check
- * will suffice.
- */
- if (hctx->flags & BLK_MQ_F_TAG_SHARED)
- no_tag = true;
- break;
- }
- }
list_del_init(&rq->queuelist);
@@ -1363,6 +1373,10 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
*/
if (!list_empty(list)) {
bool needs_restart;
+ /* For non-shared tags, the RESTART check will suffice */
+ bool no_tag = prep == PREP_DISPATCH_NO_TAG &&
+ (hctx->flags & BLK_MQ_F_TAG_SHARED);
+ bool no_budget_avail = prep == PREP_DISPATCH_NO_BUDGET;
/*
* If we didn't flush the entire list, we could have told
--
2.25.2
next prev parent reply other threads:[~2020-06-24 23:04 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-24 23:03 [PATCH V6 0/6] blk-mq: support batching dispatch from scheduler Ming Lei
2020-06-24 23:03 ` [PATCH V6 1/6] blk-mq: pass request queue into get/put budget callback Ming Lei
2020-06-24 23:03 ` [PATCH V6 2/6] blk-mq: pass hctx to blk_mq_dispatch_rq_list Ming Lei
2020-06-24 23:03 ` Ming Lei [this message]
2020-06-24 23:03 ` [PATCH V6 4/6] blk-mq: remove dead check from blk_mq_dispatch_rq_list Ming Lei
2020-06-25 7:42 ` Johannes Thumshirn
2020-06-24 23:03 ` [PATCH V6 5/6] blk-mq: pass obtained budget count to blk_mq_dispatch_rq_list Ming Lei
2020-06-29 8:11 ` Christoph Hellwig
2020-06-24 23:03 ` [PATCH V6 6/6] blk-mq: support batching dispatch in case of io scheduler Ming Lei
2020-06-29 9:04 ` Christoph Hellwig
2020-06-29 10:32 ` Ming Lei
2020-06-30 0:57 ` Ming Lei
2020-06-30 4:56 ` Christoph Hellwig
2020-06-30 4:55 ` Christoph Hellwig
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