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From: Sagi Grimberg <sagi@grimberg.me>
To: linux-block@vger.kernel.org, linux-nvme@lists.infradead.org,
	linux-rdma@vger.kernel.org, target-devel@vger.kernel.org
Subject: [PATCH rfc 09/10] nvmet: Use non-selective polling
Date: Thu,  9 Mar 2017 15:16:41 +0200	[thread overview]
Message-ID: <1489065402-14757-10-git-send-email-sagi@grimberg.me> (raw)
In-Reply-To: <1489065402-14757-1-git-send-email-sagi@grimberg.me>

It doesn't really make sense to do selective polling
because we never care about specific IOs. Non selective
polling can actually help by doing some useful work
while we're submitting a command.

We ask for a batch of (magic) 4 completions which looks
like a decent network<->backend proportion, if less are
available we'll see less.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
---
 drivers/nvme/target/io-cmd.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/target/io-cmd.c b/drivers/nvme/target/io-cmd.c
index 4195115c7e54..8e4fd7ca4a8a 100644
--- a/drivers/nvme/target/io-cmd.c
+++ b/drivers/nvme/target/io-cmd.c
@@ -46,7 +46,6 @@ static void nvmet_execute_rw(struct nvmet_req *req)
 	struct scatterlist *sg;
 	struct bio *bio;
 	sector_t sector;
-	blk_qc_t cookie;
 	int op, op_flags = 0, i;
 
 	if (!req->sg_cnt) {
@@ -85,16 +84,17 @@ static void nvmet_execute_rw(struct nvmet_req *req)
 			bio_set_op_attrs(bio, op, op_flags);
 
 			bio_chain(bio, prev);
-			cookie = submit_bio(prev);
+			submit_bio(prev);
 		}
 
 		sector += sg->length >> 9;
 		sg_cnt--;
 	}
 
-	cookie = submit_bio(bio);
+	submit_bio(bio);
 
-	blk_mq_poll(bdev_get_queue(req->ns->bdev), cookie);
+	/* magic 4 is what we are willing to grab before we return */
+	blk_mq_poll_batch(bdev_get_queue(req->ns->bdev), 4);
 }
 
 static void nvmet_execute_flush(struct nvmet_req *req)
-- 
2.7.4


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  parent reply	other threads:[~2017-03-09 13:16 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-09 13:16 [PATCH rfc 00/10] non selective polling block interface Sagi Grimberg
2017-03-09 13:16 ` [PATCH rfc 01/10] nvme-pci: Split __nvme_process_cq to poll and handle Sagi Grimberg
2017-03-09 13:57   ` Johannes Thumshirn
2017-03-22 19:07   ` Christoph Hellwig
2017-03-09 13:16 ` [PATCH rfc 02/10] nvme-pci: Add budget to __nvme_process_cq Sagi Grimberg
2017-03-09 13:46   ` Johannes Thumshirn
2017-03-22 19:08   ` Christoph Hellwig
2017-03-09 13:16 ` [PATCH rfc 03/10] nvme-pci: open-code polling logic in nvme_poll Sagi Grimberg
2017-03-09 13:56   ` Johannes Thumshirn
2017-03-22 19:09   ` Christoph Hellwig
2017-03-09 13:16 ` [PATCH rfc 04/10] block: Add a non-selective polling interface Sagi Grimberg
2017-03-09 13:44   ` Johannes Thumshirn
2017-03-10  3:04     ` Damien Le Moal
2017-03-13  8:26       ` Sagi Grimberg
2017-03-09 16:25   ` Bart Van Assche
2017-03-13  8:15     ` Sagi Grimberg
2017-03-14 21:21       ` Bart Van Assche
2017-03-09 13:16 ` [PATCH rfc 05/10] nvme-pci: Support blk_poll_batch Sagi Grimberg
2017-03-09 13:16 ` [PATCH rfc 06/10] IB/cq: Don't force IB_POLL_DIRECT poll context for ib_process_cq_direct Sagi Grimberg
2017-03-09 16:30   ` Bart Van Assche
2017-03-13  8:24     ` Sagi Grimberg
2017-03-14 21:32       ` Bart Van Assche
2017-03-09 13:16 ` [PATCH rfc 07/10] nvme-rdma: Don't rearm the CQ when polling directly Sagi Grimberg
2017-03-09 13:52   ` Johannes Thumshirn
2017-03-09 13:16 ` [PATCH rfc 08/10] nvme-rdma: Support blk_poll_batch Sagi Grimberg
2017-03-09 13:16 ` Sagi Grimberg [this message]
2017-03-09 13:54   ` [PATCH rfc 09/10] nvmet: Use non-selective polling Johannes Thumshirn
2017-03-09 13:16 ` [PATCH rfc 10/10] target: " Sagi Grimberg
2017-03-18 23:58   ` Nicholas A. Bellinger
2017-03-21 11:35     ` Sagi Grimberg

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