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From: Jens Axboe <axboe@kernel.dk>
To: linux-block@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 08/11] block: make blk_poll() take a parameter on whether to spin or not
Date: Thu, 15 Nov 2018 12:51:32 -0700	[thread overview]
Message-ID: <20181115195135.22812-9-axboe@kernel.dk> (raw)
In-Reply-To: <20181115195135.22812-1-axboe@kernel.dk>

blk_poll() has always kept spinning until it found an IO. This is
fine for SYNC polling, since we need to find one request we have
pending, but in preparation for ASYNC polling it can be beneficial
to just check if we have any entries available or not.

Existing callers are converted to pass in 'spin == true', to retain
the old behavior.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 block/blk-core.c                  |  4 ++--
 block/blk-mq.c                    | 10 +++++-----
 drivers/nvme/host/multipath.c     |  4 ++--
 drivers/nvme/target/io-cmd-bdev.c |  2 +-
 fs/block_dev.c                    |  4 ++--
 fs/direct-io.c                    |  2 +-
 fs/iomap.c                        |  2 +-
 include/linux/blkdev.h            |  4 ++--
 mm/page_io.c                      |  2 +-
 9 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 0b684a520a11..ccf40f853afd 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1284,14 +1284,14 @@ blk_qc_t submit_bio(struct bio *bio)
 }
 EXPORT_SYMBOL(submit_bio);
 
-bool blk_poll(struct request_queue *q, blk_qc_t cookie)
+bool blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
 {
 	if (!q->poll_fn || !blk_qc_t_valid(cookie))
 		return false;
 
 	if (current->plug)
 		blk_flush_plug_list(current->plug, false);
-	return q->poll_fn(q, cookie);
+	return q->poll_fn(q, cookie, spin);
 }
 EXPORT_SYMBOL_GPL(blk_poll);
 
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 3ca00d712158..695aa9363a6e 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -38,7 +38,7 @@
 #include "blk-mq-sched.h"
 #include "blk-rq-qos.h"
 
-static int blk_mq_poll(struct request_queue *q, blk_qc_t cookie);
+static int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, bool spin);
 static void blk_mq_poll_stats_start(struct request_queue *q);
 static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb);
 
@@ -3328,7 +3328,7 @@ static bool blk_mq_poll_hybrid(struct request_queue *q,
 	return blk_mq_poll_hybrid_sleep(q, hctx, rq);
 }
 
-static int __blk_mq_poll(struct blk_mq_hw_ctx *hctx)
+static int __blk_mq_poll(struct blk_mq_hw_ctx *hctx, bool spin)
 {
 	struct request_queue *q = hctx->queue;
 	long state;
@@ -3353,7 +3353,7 @@ static int __blk_mq_poll(struct blk_mq_hw_ctx *hctx)
 
 		if (current->state == TASK_RUNNING)
 			return 1;
-		if (ret < 0)
+		if (ret < 0 || !spin)
 			break;
 		cpu_relax();
 	}
@@ -3362,7 +3362,7 @@ static int __blk_mq_poll(struct blk_mq_hw_ctx *hctx)
 	return 0;
 }
 
-static int blk_mq_poll(struct request_queue *q, blk_qc_t cookie)
+static int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
 {
 	struct blk_mq_hw_ctx *hctx;
 
@@ -3381,7 +3381,7 @@ static int blk_mq_poll(struct request_queue *q, blk_qc_t cookie)
 	if (blk_mq_poll_hybrid(q, hctx, cookie))
 		return 1;
 
-	return __blk_mq_poll(hctx);
+	return __blk_mq_poll(hctx, spin);
 }
 
 unsigned int blk_mq_rq_cpu(struct request *rq)
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 65539c8df11d..c83bb3302684 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -220,7 +220,7 @@ static blk_qc_t nvme_ns_head_make_request(struct request_queue *q,
 	return ret;
 }
 
-static int nvme_ns_head_poll(struct request_queue *q, blk_qc_t qc)
+static int nvme_ns_head_poll(struct request_queue *q, blk_qc_t qc, bool spin)
 {
 	struct nvme_ns_head *head = q->queuedata;
 	struct nvme_ns *ns;
@@ -230,7 +230,7 @@ static int nvme_ns_head_poll(struct request_queue *q, blk_qc_t qc)
 	srcu_idx = srcu_read_lock(&head->srcu);
 	ns = srcu_dereference(head->current_path[numa_node_id()], &head->srcu);
 	if (likely(ns && nvme_path_is_optimized(ns)))
-		found = ns->queue->poll_fn(q, qc);
+		found = ns->queue->poll_fn(q, qc, spin);
 	srcu_read_unlock(&head->srcu, srcu_idx);
 	return found;
 }
diff --git a/drivers/nvme/target/io-cmd-bdev.c b/drivers/nvme/target/io-cmd-bdev.c
index c1ec3475a140..f6971b45bc54 100644
--- a/drivers/nvme/target/io-cmd-bdev.c
+++ b/drivers/nvme/target/io-cmd-bdev.c
@@ -116,7 +116,7 @@ static void nvmet_bdev_execute_rw(struct nvmet_req *req)
 
 	cookie = submit_bio(bio);
 
-	blk_poll(bdev_get_queue(req->ns->bdev), cookie);
+	blk_poll(bdev_get_queue(req->ns->bdev), cookie, true);
 }
 
 static void nvmet_bdev_execute_flush(struct nvmet_req *req)
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 0ed9be8906a8..7810f5b588ea 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -244,7 +244,7 @@ __blkdev_direct_IO_simple(struct kiocb *iocb, struct iov_iter *iter,
 			break;
 
 		if (!(iocb->ki_flags & IOCB_HIPRI) ||
-		    !blk_poll(bdev_get_queue(bdev), qc))
+		    !blk_poll(bdev_get_queue(bdev), qc, true))
 			io_schedule();
 	}
 	__set_current_state(TASK_RUNNING);
@@ -413,7 +413,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
 			break;
 
 		if (!(iocb->ki_flags & IOCB_HIPRI) ||
-		    !blk_poll(bdev_get_queue(bdev), qc))
+		    !blk_poll(bdev_get_queue(bdev), qc, true))
 			io_schedule();
 	}
 	__set_current_state(TASK_RUNNING);
diff --git a/fs/direct-io.c b/fs/direct-io.c
index ea07d5a34317..a5a4e5a1423e 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -518,7 +518,7 @@ static struct bio *dio_await_one(struct dio *dio)
 		dio->waiter = current;
 		spin_unlock_irqrestore(&dio->bio_lock, flags);
 		if (!(dio->iocb->ki_flags & IOCB_HIPRI) ||
-		    !blk_poll(dio->bio_disk->queue, dio->bio_cookie))
+		    !blk_poll(dio->bio_disk->queue, dio->bio_cookie, true))
 			io_schedule();
 		/* wake up sets us TASK_RUNNING */
 		spin_lock_irqsave(&dio->bio_lock, flags);
diff --git a/fs/iomap.c b/fs/iomap.c
index 38c9bc63296a..1ef4e063f068 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -1897,7 +1897,7 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 			if (!(iocb->ki_flags & IOCB_HIPRI) ||
 			    !dio->submit.last_queue ||
 			    !blk_poll(dio->submit.last_queue,
-					 dio->submit.cookie))
+					 dio->submit.cookie, true))
 				io_schedule();
 		}
 		__set_current_state(TASK_RUNNING);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index e96dc16ef8aa..e83ad6f15281 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -283,7 +283,7 @@ static inline unsigned short req_get_ioprio(struct request *req)
 struct blk_queue_ctx;
 
 typedef blk_qc_t (make_request_fn) (struct request_queue *q, struct bio *bio);
-typedef int (poll_q_fn) (struct request_queue *q, blk_qc_t);
+typedef int (poll_q_fn) (struct request_queue *q, blk_qc_t, bool spin);
 
 struct bio_vec;
 typedef int (dma_drain_needed_fn)(struct request *);
@@ -868,7 +868,7 @@ extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
 int blk_status_to_errno(blk_status_t status);
 blk_status_t errno_to_blk_status(int errno);
 
-bool blk_poll(struct request_queue *q, blk_qc_t cookie);
+bool blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin);
 
 static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
 {
diff --git a/mm/page_io.c b/mm/page_io.c
index f277459db805..1518f459866d 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -411,7 +411,7 @@ int swap_readpage(struct page *page, bool synchronous)
 		if (!READ_ONCE(bio->bi_private))
 			break;
 
-		if (!blk_poll(disk->queue, qc))
+		if (!blk_poll(disk->queue, qc, true))
 			break;
 	}
 	__set_current_state(TASK_RUNNING);
-- 
2.17.1


  parent reply	other threads:[~2018-11-15 19:51 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-15 19:51 [PATCHSET v2 0/11] Various block optimizations Jens Axboe
2018-11-15 19:51 ` [PATCH 01/11] nvme: provide optimized poll function for separate poll queues Jens Axboe
2018-11-16  8:35   ` Christoph Hellwig
2018-11-16 15:22     ` Jens Axboe
2018-11-15 19:51 ` [PATCH 02/11] block: add queue_is_mq() helper Jens Axboe
2018-11-16  8:35   ` Christoph Hellwig
2018-11-15 19:51 ` [PATCH 03/11] blk-rq-qos: inline check for q->rq_qos functions Jens Axboe
2018-11-16  8:38   ` Christoph Hellwig
2018-11-16 15:18     ` Jens Axboe
2018-11-15 19:51 ` [PATCH 04/11] block: avoid ordered task state change for polled IO Jens Axboe
2018-11-16  8:41   ` Christoph Hellwig
2018-11-16 15:32     ` Jens Axboe
2018-11-15 19:51 ` [PATCH 05/11] block: add polled wakeup task helper Jens Axboe
2018-11-16  8:41   ` Christoph Hellwig
2018-11-15 19:51 ` [PATCH 06/11] block: have ->poll_fn() return number of entries polled Jens Axboe
2018-11-15 19:51 ` [PATCH 07/11] blk-mq: when polling for IO, look for any completion Jens Axboe
2018-11-16  8:43   ` Christoph Hellwig
2018-11-16 15:19     ` Jens Axboe
2018-11-16 16:57       ` Jens Axboe
2018-11-15 19:51 ` Jens Axboe [this message]
2018-11-15 19:51 ` [PATCH 09/11] blk-mq: ensure mq_ops ->poll() is entered at least once Jens Axboe
2018-11-15 19:51 ` [PATCH 10/11] block: for async O_DIRECT, mark us as polling if asked to Jens Axboe
2018-11-16  8:47   ` Christoph Hellwig
2018-11-16  8:48     ` Christoph Hellwig
2018-11-16 15:19       ` Jens Axboe
2018-11-15 19:51 ` [PATCH 11/11] block: don't plug for aio/O_DIRECT HIPRI IO Jens Axboe
2018-11-16  8:49   ` Christoph Hellwig

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