[PATCH] virtio_blk: merge S/G list entries by default
From: Christoph Hellwig <hch@lst.de>
Date: 2014-09-06 23:07:38
Also in:
lkml
Subsystem:
block layer, the rest, virtio block and scsi drivers, virtio core · Maintainers:
Jens Axboe, Linus Torvalds, "Michael S. Tsirkin", Jason Wang, Eugenio Pérez
Most virtio setups have a fairly limited number of ring entries available. Enable S/G entry merging by default to fit into less of them. This restores the behavior at time of the virtio-blk blk-mq conversion, which was changed by commit "block: add queue flag for disabling SG merging" which made the behavior optional, but didn't update the existing drivers to keep their previous behavior. Signed-off-by: Christoph Hellwig <hch@lst.de> --- drivers/block/virtio_blk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 0a58140..311b857 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c@@ -634,7 +634,7 @@ static int virtblk_probe(struct virtio_device *vdev) vblk->tag_set.ops = &virtio_mq_ops; vblk->tag_set.queue_depth = virtblk_queue_depth; vblk->tag_set.numa_node = NUMA_NO_NODE; - vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; + vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE; vblk->tag_set.cmd_size = sizeof(struct virtblk_req) + sizeof(struct scatterlist) * sg_elems;
--
1.9.1