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

[Asias He <asias@redhat.com>]

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