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From: Jens Axboe <axboe@kernel.dk>
To: linux-block@vger.kernel.org, linux-nvme@lists.infradead.org
Cc: Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 7/7] blk-mq: ensure mq_ops ->poll() is entered at least once
Date: Sat, 17 Nov 2018 14:43:54 -0700	[thread overview]
Message-ID: <20181117214354.822-8-axboe@kernel.dk> (raw)
In-Reply-To: <20181117214354.822-1-axboe@kernel.dk>

Right now we immediately bail if need_resched() is true, but
we need to do at least one loop in case we have entries waiting.
So just invert the need_resched() check, putting it at the
bottom of the loop.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 block/blk-mq.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 0a2847d9248b..4769c975b8c8 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -3336,7 +3336,7 @@ static int __blk_mq_poll(struct blk_mq_hw_ctx *hctx, bool spin)
 	hctx->poll_considered++;
 
 	state = current->state;
-	while (!need_resched()) {
+	do {
 		int ret;
 
 		hctx->poll_invoked++;
@@ -3356,7 +3356,7 @@ static int __blk_mq_poll(struct blk_mq_hw_ctx *hctx, bool spin)
 		if (ret < 0 || !spin)
 			break;
 		cpu_relax();
-	}
+	} while (!need_resched());
 
 	__set_current_state(TASK_RUNNING);
 	return 0;
-- 
2.17.1


WARNING: multiple messages have this Message-ID (diff)
From: axboe@kernel.dk (Jens Axboe)
Subject: [PATCH 7/7] blk-mq: ensure mq_ops ->poll() is entered at least once
Date: Sat, 17 Nov 2018 14:43:54 -0700	[thread overview]
Message-ID: <20181117214354.822-8-axboe@kernel.dk> (raw)
In-Reply-To: <20181117214354.822-1-axboe@kernel.dk>

Right now we immediately bail if need_resched() is true, but
we need to do at least one loop in case we have entries waiting.
So just invert the need_resched() check, putting it at the
bottom of the loop.

Signed-off-by: Jens Axboe <axboe at kernel.dk>
---
 block/blk-mq.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 0a2847d9248b..4769c975b8c8 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -3336,7 +3336,7 @@ static int __blk_mq_poll(struct blk_mq_hw_ctx *hctx, bool spin)
 	hctx->poll_considered++;
 
 	state = current->state;
-	while (!need_resched()) {
+	do {
 		int ret;
 
 		hctx->poll_invoked++;
@@ -3356,7 +3356,7 @@ static int __blk_mq_poll(struct blk_mq_hw_ctx *hctx, bool spin)
 		if (ret < 0 || !spin)
 			break;
 		cpu_relax();
-	}
+	} while (!need_resched());
 
 	__set_current_state(TASK_RUNNING);
 	return 0;
-- 
2.17.1

  parent reply	other threads:[~2018-11-17 21:44 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-17 21:43 [PATCHSET v4] Various block optimizations Jens Axboe
2018-11-17 21:43 ` Jens Axboe
2018-11-17 21:43 ` [PATCH 1/7] block: avoid ordered task state change for polled IO Jens Axboe
2018-11-17 21:43   ` Jens Axboe
2018-11-19  7:58   ` Christoph Hellwig
2018-11-19  7:58     ` Christoph Hellwig
2018-11-17 21:43 ` [PATCH 2/7] block: have ->poll_fn() return number of entries polled Jens Axboe
2018-11-17 21:43   ` Jens Axboe
2018-11-19  7:58   ` Christoph Hellwig
2018-11-19  7:58     ` Christoph Hellwig
2018-11-25 10:52   ` Sagi Grimberg
2018-11-25 10:52     ` Sagi Grimberg
2018-11-25 13:41     ` Jens Axboe
2018-11-25 13:41       ` Jens Axboe
2018-11-27 10:10       ` Sagi Grimberg
2018-11-27 10:10         ` Sagi Grimberg
2018-11-27 15:20         ` Jens Axboe
2018-11-27 15:20           ` Jens Axboe
2018-11-17 21:43 ` [PATCH 3/7] nvme-fc: remove unused poll implementation Jens Axboe
2018-11-17 21:43   ` Jens Axboe
2018-11-19  7:59   ` Christoph Hellwig
2018-11-19  7:59     ` Christoph Hellwig
2018-11-19 15:19     ` Jens Axboe
2018-11-19 15:19       ` Jens Axboe
2018-11-19 19:00       ` James Smart
2018-11-19 19:00         ` James Smart
2018-11-17 21:43 ` [PATCH 4/7] blk-mq: when polling for IO, look for any completion Jens Axboe
2018-11-17 21:43   ` Jens Axboe
2018-11-19  8:02   ` Christoph Hellwig
2018-11-19  8:02     ` Christoph Hellwig
2018-11-19 15:20     ` Jens Axboe
2018-11-19 15:20       ` Jens Axboe
2018-11-17 21:43 ` [PATCH 5/7] blk-mq: remove 'tag' parameter from mq_ops->poll() Jens Axboe
2018-11-17 21:43   ` Jens Axboe
2018-11-19  8:02   ` Christoph Hellwig
2018-11-19  8:02     ` Christoph Hellwig
2018-11-17 21:43 ` [PATCH 6/7] block: make blk_poll() take a parameter on whether to spin or not Jens Axboe
2018-11-17 21:43   ` Jens Axboe
2018-11-19  8:05   ` Christoph Hellwig
2018-11-19  8:05     ` Christoph Hellwig
2018-11-19 15:21     ` Jens Axboe
2018-11-19 15:21       ` Jens Axboe
2018-11-20  9:11       ` Sagi Grimberg
2018-11-20  9:11         ` Sagi Grimberg
2018-11-17 21:43 ` Jens Axboe [this message]
2018-11-17 21:43   ` [PATCH 7/7] blk-mq: ensure mq_ops ->poll() is entered at least once Jens Axboe
2018-11-19  8:05   ` Christoph Hellwig
2018-11-19  8:05     ` Christoph Hellwig

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