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From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>,
	Ming Lei <ming.lei@redhat.com>,
	Damien Le Moal <Damien.LeMoal@wdc.com>,
	Keith Busch <kbusch@kernel.org>, Sagi Grimberg <sagi@grimberg.me>,
	"Wunderlich, Mark" <mark.wunderlich@intel.com>,
	"Vasudevan, Anil" <anil.vasudevan@intel.com>,
	linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-nvme@lists.infradead.org
Subject: [PATCH 09/16] io_uring: don't sleep when polling for I/O
Date: Tue, 15 Jun 2021 15:10:27 +0200	[thread overview]
Message-ID: <20210615131034.752623-10-hch@lst.de> (raw)
In-Reply-To: <20210615131034.752623-1-hch@lst.de>

There is no point in sleeping for the expected I/O completion timeout
in the io_uring async polling model as we never poll for a specific
I/O.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
---
 block/blk-mq.c         | 3 ++-
 fs/io_uring.c          | 2 +-
 include/linux/blkdev.h | 2 ++
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index c2b2c7abd712..86e59ffcca44 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -4002,7 +4002,8 @@ int blk_poll(struct request_queue *q, blk_qc_t cookie, unsigned int flags)
 	if (current->plug)
 		blk_flush_plug_list(current->plug, false);
 
-	if (q->poll_nsec != BLK_MQ_POLL_CLASSIC) {
+	if (!(flags & BLK_POLL_NOSLEEP) &&
+	    q->poll_nsec != BLK_MQ_POLL_CLASSIC) {
 		if (blk_mq_poll_hybrid(q, cookie))
 			return 1;
 	}
diff --git a/fs/io_uring.c b/fs/io_uring.c
index de8d39e9a154..6ce1e5b60725 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2290,7 +2290,7 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
 static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
 			long min)
 {
-	unsigned int poll_flags = 0;
+	unsigned int poll_flags = BLK_POLL_NOSLEEP;
 	struct io_kiocb *req, *tmp;
 	LIST_HEAD(done);
 	int ret = 0;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index c7061f25ee5f..821d721f78e7 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -948,6 +948,8 @@ blk_status_t errno_to_blk_status(int errno);
 
 /* only poll the hardware once, don't continue until a completion was found */
 #define BLK_POLL_ONESHOT		(1 << 0)
+/* do not sleep to wait for the expected completion time */
+#define BLK_POLL_NOSLEEP		(1 << 1)
 int blk_poll(struct request_queue *q, blk_qc_t cookie, unsigned int flags);
 
 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
-- 
2.30.2


WARNING: multiple messages have this Message-ID
From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>,
	Ming Lei <ming.lei@redhat.com>,
	Damien Le Moal <Damien.LeMoal@wdc.com>,
	Keith Busch <kbusch@kernel.org>, Sagi Grimberg <sagi@grimberg.me>,
	"Wunderlich, Mark" <mark.wunderlich@intel.com>,
	"Vasudevan, Anil" <anil.vasudevan@intel.com>,
	linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-nvme@lists.infradead.org
Subject: [PATCH 09/16] io_uring: don't sleep when polling for I/O
Date: Tue, 15 Jun 2021 15:10:27 +0200	[thread overview]
Message-ID: <20210615131034.752623-10-hch@lst.de> (raw)
In-Reply-To: <20210615131034.752623-1-hch@lst.de>

There is no point in sleeping for the expected I/O completion timeout
in the io_uring async polling model as we never poll for a specific
I/O.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
---
 block/blk-mq.c         | 3 ++-
 fs/io_uring.c          | 2 +-
 include/linux/blkdev.h | 2 ++
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index c2b2c7abd712..86e59ffcca44 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -4002,7 +4002,8 @@ int blk_poll(struct request_queue *q, blk_qc_t cookie, unsigned int flags)
 	if (current->plug)
 		blk_flush_plug_list(current->plug, false);
 
-	if (q->poll_nsec != BLK_MQ_POLL_CLASSIC) {
+	if (!(flags & BLK_POLL_NOSLEEP) &&
+	    q->poll_nsec != BLK_MQ_POLL_CLASSIC) {
 		if (blk_mq_poll_hybrid(q, cookie))
 			return 1;
 	}
diff --git a/fs/io_uring.c b/fs/io_uring.c
index de8d39e9a154..6ce1e5b60725 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2290,7 +2290,7 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
 static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
 			long min)
 {
-	unsigned int poll_flags = 0;
+	unsigned int poll_flags = BLK_POLL_NOSLEEP;
 	struct io_kiocb *req, *tmp;
 	LIST_HEAD(done);
 	int ret = 0;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index c7061f25ee5f..821d721f78e7 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -948,6 +948,8 @@ blk_status_t errno_to_blk_status(int errno);
 
 /* only poll the hardware once, don't continue until a completion was found */
 #define BLK_POLL_ONESHOT		(1 << 0)
+/* do not sleep to wait for the expected completion time */
+#define BLK_POLL_NOSLEEP		(1 << 1)
 int blk_poll(struct request_queue *q, blk_qc_t cookie, unsigned int flags);
 
 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
-- 
2.30.2


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  parent reply	other threads:[~2021-06-15 13:14 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-15 13:10 switch block layer polling to a bio based model v4 Christoph Hellwig
2021-06-15 13:10 ` [PATCH 01/16] direct-io: remove blk_poll support Christoph Hellwig
2021-06-15 13:10 ` [PATCH 02/16] block: don't try to poll multi-bio I/Os in __blkdev_direct_IO Christoph Hellwig
2021-06-15 13:10 ` [PATCH 03/16] iomap: don't try to poll multi-bio I/Os in __iomap_dio_rw Christoph Hellwig
2021-06-15 13:10 ` [PATCH 04/16] blk-mq: factor out a blk_qc_to_hctx helper Christoph Hellwig
2021-06-15 13:10 ` [PATCH 05/16] blk-mq: factor out a "classic" poll helper Christoph Hellwig
2021-06-15 13:10 ` [PATCH 06/16] blk-mq: remove blk_qc_t_to_tag and blk_qc_t_is_internal Christoph Hellwig
2021-06-15 13:10 ` [PATCH 07/16] blk-mq: remove blk_qc_t_valid Christoph Hellwig
2021-06-15 13:10 ` [PATCH 08/16] block: replace the spin argument to blk_iopoll with a flags argument Christoph Hellwig
2021-06-15 13:10 ` Christoph Hellwig [this message]
2021-06-15 13:10 ` [PATCH 10/16] block: rename REQ_HIPRI to REQ_POLLED Christoph Hellwig
2021-06-15 13:10 ` [PATCH 11/16] block: use SLAB_TYPESAFE_BY_RCU for the bio slab Christoph Hellwig
2021-06-15 13:10 ` [PATCH 12/16] block: define 'struct bvec_iter' as packed Christoph Hellwig
2021-06-15 13:10 ` [PATCH 13/16] block: switch polling to be bio based Christoph Hellwig
2021-06-16  2:30   ` Ming Lei
2021-06-18 14:01     ` Christoph Hellwig
2021-06-18 14:27       ` Ming Lei
2021-06-21  7:20         ` Christoph Hellwig
2021-06-21  8:35           ` Ming Lei
2021-06-15 13:10 ` [PATCH 14/16] block: don't allow writing to the poll queue attribute Christoph Hellwig
2021-06-15 13:10 ` [PATCH 15/16] nvme-multipath: set QUEUE_FLAG_NOWAIT Christoph Hellwig
2021-06-15 13:10 ` [PATCH 16/16] nvme-multipath: enable polled I/O Christoph Hellwig
2021-06-15 14:37 ` switch block layer polling to a bio based model v4 Keith Busch
2021-06-15 16:06   ` Christoph Hellwig

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