Re: [PATCH] virtio_blk: Drop unused request tracking list

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On 04/01/2012 06:07 PM, Michael S. Tsirkin wrote:
On Fri, Mar 30, 2012 at 11:24:10AM +0800, Asias He wrote:
Benchmark shows small performance improvement on fusion io device.

Before:
   seq-read : io=1,024MB, bw=19,982KB/s, iops=39,964, runt= 52475msec
   seq-write: io=1,024MB, bw=20,321KB/s, iops=40,641, runt= 51601msec
   rnd-read : io=1,024MB, bw=15,404KB/s, iops=30,808, runt= 68070msec
   rnd-write: io=1,024MB, bw=14,776KB/s, iops=29,552, runt= 70963msec

After:
   seq-read : io=1,024MB, bw=20,343KB/s, iops=40,685, runt= 51546msec
   seq-write: io=1,024MB, bw=20,803KB/s, iops=41,606, runt= 50404msec
   rnd-read : io=1,024MB, bw=16,221KB/s, iops=32,442, runt= 64642msec
   rnd-write: io=1,024MB, bw=15,199KB/s, iops=30,397, runt= 68991msec

Signed-off-by: Asias He<asias@xxxxxxxxxx>

Thanks, the patch makes sense to me.
Acked-by: Michael S. Tsirkin<mst@xxxxxxxxxx>

This is 3.5 material, correct?

Yes, I think so.


---
  drivers/block/virtio_blk.c |   10 ----------
  1 files changed, 0 insertions(+), 10 deletions(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index c4a60ba..338da9a 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -29,9 +29,6 @@ struct virtio_blk
  	/* The disk structure for the kernel. */
  	struct gendisk *disk;

-	/* Request tracking. */
-	struct list_head reqs;
-
  	mempool_t *pool;

  	/* Process context for config space updates */
@@ -55,7 +52,6 @@ struct virtio_blk

  struct virtblk_req
  {
-	struct list_head list;
  	struct request *req;
  	struct virtio_blk_outhdr out_hdr;
  	struct virtio_scsi_inhdr in_hdr;
@@ -99,7 +95,6 @@ static void blk_done(struct virtqueue *vq)
  		}

  		__blk_end_request_all(vbr->req, error);
-		list_del(&vbr->list);
  		mempool_free(vbr, vblk->pool);
  	}
  	/* In case queue is stopped waiting for more buffers. */
@@ -184,7 +179,6 @@ static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
  		return false;
  	}

-	list_add_tail(&vbr->list,&vblk->reqs);
  	return true;
  }

@@ -408,7 +402,6 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
  		goto out_free_index;
  	}

-	INIT_LIST_HEAD(&vblk->reqs);
  	spin_lock_init(&vblk->lock);
  	vblk->vdev = vdev;
  	vblk->sg_elems = sg_elems;
@@ -571,9 +564,6 @@ static void __devexit virtblk_remove(struct virtio_device *vdev)
  	vblk->config_enable = false;
  	mutex_unlock(&vblk->config_lock);

-	/* Nothing should be pending. */
-	BUG_ON(!list_empty(&vblk->reqs));
-
  	/* Stop all the virtqueues. */
  	vdev->config->reset(vdev);

--
1.7.7.6
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--
Asias
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