* [PATCH V3 1/4] blk-mq: refactor the code of issue request directly
2018-10-29 8:33 [PATCH V3 0/4] blk-mq: refactor and fix on issue request directly Jianchao Wang
@ 2018-10-29 8:33 ` Jianchao Wang
2018-10-29 8:42 ` jianchao.wang
2018-10-29 8:33 ` [PATCH V3 2/4] blk-mq: insert request without involving any io scheduler Jianchao Wang
` (2 subsequent siblings)
3 siblings, 1 reply; 6+ messages in thread
From: Jianchao Wang @ 2018-10-29 8:33 UTC (permalink / raw)
To: axboe; +Cc: ming.lei, linux-block, linux-kernel
Merge blk_mq_try_issue_directly and __blk_mq_try_issue_directly
into one interface which is able to handle the return value from
.queue_rq callback. To make the code clearer, introduce new helpers
blk_mq_make_decision and enum mq_decision.
Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>
---
block/blk-mq.c | 104 ++++++++++++++++++++++++++++++-----------------------
block/blk-mq.c.rej | 60 +++++++++++++++++++++++++++++++
2 files changed, 120 insertions(+), 44 deletions(-)
create mode 100644 block/blk-mq.c.rej
diff --git a/block/blk-mq.c b/block/blk-mq.c
index dcf10e3..0f6328b 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1711,7 +1711,6 @@ static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
switch (ret) {
case BLK_STS_OK:
blk_mq_update_dispatch_busy(hctx, false);
- *cookie = new_cookie;
break;
case BLK_STS_RESOURCE:
case BLK_STS_DEV_RESOURCE:
@@ -1720,86 +1719,103 @@ static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
break;
default:
blk_mq_update_dispatch_busy(hctx, false);
- *cookie = BLK_QC_T_NONE;
+ new_cookie = BLK_QC_T_NONE;
break;
}
+ if (cookie)
+ *cookie = new_cookie;
return ret;
}
-static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
+enum mq_decision {
+ MQ_INSERT_QUEUE,
+ MQ_END_REQUEST,
+ MQ_DO_NOTHING,
+};
+
+static inline enum mq_decision
+ blk_mq_make_dicision(blk_status_t ret, bool bypass_insert)
+{
+ enum mq_decision dec;
+
+ switch(ret) {
+ case BLK_STS_OK:
+ dec = MQ_DO_NOTHING;
+ break;
+ case BLK_STS_DEV_RESOURCE:
+ case BLK_STS_RESOURCE:
+ dec = bypass_insert ? MQ_DO_NOTHING : MQ_INSERT_QUEUE;
+ break;
+ default:
+ dec = bypass_insert ? MQ_DO_NOTHING : MQ_END_REQUEST;
+ break;
+ }
+
+ return dec;
+}
+
+static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
struct request *rq,
blk_qc_t *cookie,
bool bypass_insert)
{
struct request_queue *q = rq->q;
bool run_queue = true;
+ enum mq_decision dec;
+ blk_status_t ret = BLK_STS_RESOURCE;
+ int srcu_idx;
+ hctx_lock(hctx, &srcu_idx);
/*
- * RCU or SRCU read lock is needed before checking quiesced flag.
+ * hctx_lock is needed before checking quiesced flag.
*
- * When queue is stopped or quiesced, ignore 'bypass_insert' from
- * blk_mq_request_issue_directly(), and return BLK_STS_OK to caller,
- * and avoid driver to try to dispatch again.
+ * When queue is stopped or quiesced, ignore 'bypass_insert',
+ * and return BLK_STS_OK to caller, and avoid driver to try to
+ * dispatch again.
*/
if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) {
run_queue = false;
bypass_insert = false;
- goto insert;
+ goto out_unlock;
}
if (q->elevator && !bypass_insert)
- goto insert;
+ goto out_unlock;
if (!blk_mq_get_dispatch_budget(hctx))
- goto insert;
+ goto out_unlock;
if (!blk_mq_get_driver_tag(rq)) {
blk_mq_put_dispatch_budget(hctx);
- goto insert;
+ goto out_unlock;
}
- return __blk_mq_issue_directly(hctx, rq, cookie);
-insert:
- if (bypass_insert)
- return BLK_STS_RESOURCE;
-
- blk_mq_sched_insert_request(rq, false, run_queue, false);
- return BLK_STS_OK;
-}
-
-static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
- struct request *rq, blk_qc_t *cookie)
-{
- blk_status_t ret;
- int srcu_idx;
-
- might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);
-
- hctx_lock(hctx, &srcu_idx);
+ ret = __blk_mq_issue_directly(hctx, rq, cookie);
+out_unlock:
+ hctx_unlock(hctx, srcu_idx);
- ret = __blk_mq_try_issue_directly(hctx, rq, cookie, false);
- if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE)
- blk_mq_sched_insert_request(rq, false, true, false);
- else if (ret != BLK_STS_OK)
+ dec = blk_mq_make_dicision(ret, bypass_insert);
+ switch(dec) {
+ case MQ_INSERT_QUEUE:
+ blk_mq_sched_insert_request(rq, false, run_queue, false);
+ break;
+ case MQ_END_REQUEST:
blk_mq_end_request(rq, ret);
+ break;
+ default:
+ return ret;
+ }
- hctx_unlock(hctx, srcu_idx);
+ return BLK_STS_OK;
}
blk_status_t blk_mq_request_issue_directly(struct request *rq)
{
- blk_status_t ret;
- int srcu_idx;
- blk_qc_t unused_cookie;
struct blk_mq_ctx *ctx = rq->mq_ctx;
struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(rq->q, ctx->cpu);
- hctx_lock(hctx, &srcu_idx);
- ret = __blk_mq_try_issue_directly(hctx, rq, &unused_cookie, true);
- hctx_unlock(hctx, srcu_idx);
-
- return ret;
+ return blk_mq_try_issue_directly(hctx, rq, NULL, true);
}
void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
@@ -1921,13 +1937,13 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
data.hctx = blk_mq_map_queue(q,
same_queue_rq->mq_ctx->cpu);
blk_mq_try_issue_directly(data.hctx, same_queue_rq,
- &cookie);
+ &cookie, false);
}
} else if ((q->nr_hw_queues > 1 && is_sync) || (!q->elevator &&
!data.hctx->dispatch_busy)) {
blk_mq_put_ctx(data.ctx);
blk_mq_bio_to_request(rq, bio);
- blk_mq_try_issue_directly(data.hctx, rq, &cookie);
+ blk_mq_try_issue_directly(data.hctx, rq, &cookie, false);
} else {
blk_mq_put_ctx(data.ctx);
blk_mq_bio_to_request(rq, bio);
diff --git a/block/blk-mq.c.rej b/block/blk-mq.c.rej
new file mode 100644
index 0000000..7813cd9
--- /dev/null
+++ b/block/blk-mq.c.rej
@@ -0,0 +1,60 @@
+--- block/blk-mq.c
++++ block/blk-mq.c
+@@ -1728,13 +1728,14 @@ static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
+ }
+
+ enum mq_decision {
++ MQ_INSERT_DISPATCH,
+ MQ_INSERT_QUEUE,
+ MQ_END_REQUEST,
+ MQ_DO_NOTHING,
+ };
+
+-static inline enum mq_decision
+- blk_mq_make_dicision(blk_status_t ret, bool bypass_insert)
++static inline enum mq_decision blk_mq_make_dicision(blk_status_t ret,
++ bool bypass_insert, bool force_insert)
+ {
+ enum mq_decision dec;
+
+@@ -1744,7 +1745,10 @@ static inline enum mq_decision
+ break;
+ case BLK_STS_DEV_RESOURCE:
+ case BLK_STS_RESOURCE:
+- dec = bypass_insert ? MQ_DO_NOTHING : MQ_INSERT_QUEUE;
++ if (force_insert)
++ dec = bypass_insert ? MQ_INSERT_DISPATCH : MQ_INSERT_QUEUE;
++ else
++ dec = bypass_insert ? MQ_DO_NOTHING : MQ_INSERT_QUEUE;
+ break;
+ default:
+ dec = bypass_insert ? MQ_DO_NOTHING : MQ_END_REQUEST;
+@@ -1760,7 +1764,7 @@ static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
+ bool bypass_insert)
+ {
+ struct request_queue *q = rq->q;
+- bool run_queue = true;
++ bool run_queue = true, force_insert = false;
+ enum mq_decision dec;
+ blk_status_t ret = BLK_STS_RESOURCE;
+ int srcu_idx;
+@@ -1775,7 +1779,7 @@ static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
+ */
+ if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) {
+ run_queue = false;
+- bypass_insert = false;
++ force_insert = true;
+ goto out_unlock;
+ }
+
+@@ -1795,7 +1799,10 @@ static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
+ hctx_unlock(hctx, srcu_idx);
+
+ dec = blk_mq_make_dicision(ret, bypass_insert);
+ switch(pos) {
++ case MQ_INSERT_DISPATCH:
++ blk_mq_request_bypass_insert(rq, run_queue);
++ break;
+ case MQ_INSERT_QUEUE:
+ blk_mq_sched_insert_request(rq, false, run_queue, false);
+ break;
--
2.7.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH V3 2/4] blk-mq: insert request without involving any io scheduler
2018-10-29 8:33 [PATCH V3 0/4] blk-mq: refactor and fix on issue request directly Jianchao Wang
2018-10-29 8:33 ` [PATCH V3 1/4] blk-mq: refactor the code of " Jianchao Wang
@ 2018-10-29 8:33 ` Jianchao Wang
2018-10-29 8:33 ` [PATCH V3 3/4] blk-mq: issue directly with bypass_insert 'false' in blk_mq_sched_insert_requests Jianchao Wang
2018-10-29 8:33 ` [PATCH V3 4/4] blk-mq: ensure hctx to be ran on mapped cpu when issue directly Jianchao Wang
3 siblings, 0 replies; 6+ messages in thread
From: Jianchao Wang @ 2018-10-29 8:33 UTC (permalink / raw)
To: axboe; +Cc: ming.lei, linux-block, linux-kernel
When try to issue request directly, if the queue is stopped or
quiesced, 'bypass_insert' will be ignored and return BLK_STS_OK to
caller to avoid it dispatch request again. Then the request will
be inserted with blk_mq_sched_insert_request. This is not correct
for dm-rq case where we should avoid to pass through the underlying
paths' io scheduler.
To fix it, use blk_mq_request_bypass_insert to insert the request
into hctx->dispatch directly.
Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>
---
block/blk-mq.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 0f6328b..e0aa068 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1729,13 +1729,14 @@ static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
}
enum mq_decision {
+ MQ_INSERT_DISPATCH,
MQ_INSERT_QUEUE,
MQ_END_REQUEST,
MQ_DO_NOTHING,
};
static inline enum mq_decision
- blk_mq_make_dicision(blk_status_t ret, bool bypass_insert)
+ blk_mq_make_dicision(blk_status_t ret, bool bypass_insert, bool force)
{
enum mq_decision dec;
@@ -1745,7 +1746,10 @@ static inline enum mq_decision
break;
case BLK_STS_DEV_RESOURCE:
case BLK_STS_RESOURCE:
- dec = bypass_insert ? MQ_DO_NOTHING : MQ_INSERT_QUEUE;
+ if (force)
+ dec = bypass_insert ? MQ_INSERT_DISPATCH : MQ_INSERT_QUEUE;
+ else
+ dec = bypass_insert ? MQ_DO_NOTHING : MQ_INSERT_QUEUE;
break;
default:
dec = bypass_insert ? MQ_DO_NOTHING : MQ_END_REQUEST;
@@ -1761,7 +1765,7 @@ static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
bool bypass_insert)
{
struct request_queue *q = rq->q;
- bool run_queue = true;
+ bool run_queue = true, force = false;
enum mq_decision dec;
blk_status_t ret = BLK_STS_RESOURCE;
int srcu_idx;
@@ -1776,7 +1780,7 @@ static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
*/
if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) {
run_queue = false;
- bypass_insert = false;
+ force = true;
goto out_unlock;
}
@@ -1795,8 +1799,11 @@ static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
out_unlock:
hctx_unlock(hctx, srcu_idx);
- dec = blk_mq_make_dicision(ret, bypass_insert);
+ dec = blk_mq_make_dicision(ret, bypass_insert, force);
switch(dec) {
+ case MQ_INSERT_DISPATCH:
+ blk_mq_request_bypass_insert(rq, run_queue);
+ break;
case MQ_INSERT_QUEUE:
blk_mq_sched_insert_request(rq, false, run_queue, false);
break;
--
2.7.4
^ permalink raw reply related [flat|nested] 6+ messages in thread