From: Jianchao Wang <jianchao.w.wang@oracle.com>
To: axboe@kernel.dk
Cc: ming.lei@redhat.com, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH V11 1/4] blk-mq: insert to hctx dispatch list when bypass_insert is true
Date: Fri, 7 Dec 2018 11:09:42 +0800 [thread overview]
Message-ID: <1544152185-32667-2-git-send-email-jianchao.w.wang@oracle.com> (raw)
In-Reply-To: <1544152185-32667-1-git-send-email-jianchao.w.wang@oracle.com>
We don't allow direct dispatch of anything but regular reads/writes
and insert all of non-read-write requests. However, this is not
correct for 'bypass_insert == true' case where inserting is ignored
and BLK_STS_RESOURCE is returned. The caller will fail forever.
Fix it with inserting the non-read-write request to hctx dispatch
list to avoid to involve merge and io scheduler when bypass_insert
is true.
Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>
---
block/blk-mq.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 9005505..01802bf 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1822,6 +1822,7 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
{
struct request_queue *q = rq->q;
bool run_queue = true;
+ bool force = false;
/*
* RCU or SRCU read lock is needed before checking quiesced flag.
@@ -1836,9 +1837,18 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
goto insert;
}
- if (!blk_rq_can_direct_dispatch(rq) || (q->elevator && !bypass_insert))
+ if (q->elevator && !bypass_insert)
goto insert;
+ if (!blk_rq_can_direct_dispatch(rq)) {
+ /*
+ * For 'bypass_insert == true' case, insert request into hctx
+ * dispatch list.
+ */
+ force = bypass_insert;
+ goto insert;
+ }
+
if (!blk_mq_get_dispatch_budget(hctx))
goto insert;
@@ -1849,8 +1859,12 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
return __blk_mq_issue_directly(hctx, rq, cookie, last);
insert:
- if (bypass_insert)
+ if (force) {
+ blk_mq_request_bypass_insert(rq, run_queue);
+ return BLK_STS_OK;
+ } else if (bypass_insert) {
return BLK_STS_RESOURCE;
+ }
blk_mq_sched_insert_request(rq, false, run_queue, false);
return BLK_STS_OK;
--
2.7.4
next prev parent reply other threads:[~2018-12-07 3:10 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-07 3:09 [PATCH V11 0/4] blk-mq: refactor code of issue directly Jianchao Wang
2018-12-07 3:09 ` Jianchao Wang [this message]
2018-12-07 3:09 ` [PATCH V11 2/4] blk-mq: refactor the code of issue request directly Jianchao Wang
2018-12-07 3:09 ` [PATCH V11 3/4] blk-mq: issue directly with bypass 'false' in blk_mq_sched_insert_requests Jianchao Wang
2018-12-07 3:09 ` [PATCH V11 4/4] blk-mq: replace and kill blk_mq_request_issue_directly Jianchao Wang
2018-12-07 3:16 ` [PATCH V11 0/4] blk-mq: refactor code of issue directly Jens Axboe
2018-12-07 3:26 ` jianchao.wang
2018-12-07 3:32 ` Jens Axboe
2018-12-07 3:34 ` Jens Axboe
2018-12-07 3:41 ` jianchao.wang
2018-12-07 3:42 ` Jens Axboe
2018-12-07 3:46 ` jianchao.wang
2018-12-07 3:47 ` Jens Axboe
2018-12-10 1:18 ` jianchao.wang
2018-12-10 1:27 ` Jens Axboe
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