From: Christoph Hellwig <hch@lst.de>
To: Rusty Russell <rusty@rustcorp.com.au>,
"Michael S. Tsirkin" <mst@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org
Subject: [PATCH] virtio_blk: merge S/G list entries by default
Date: Sat, 6 Sep 2014 16:09:54 -0700 [thread overview]
Message-ID: <1410044994-14943-1-git-send-email-hch@lst.de> (raw)
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
next reply other threads:[~2014-09-06 23:09 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-06 23:09 Christoph Hellwig [this message]
2014-09-07 10:18 ` [PATCH] virtio_blk: merge S/G list entries by default Paolo Bonzini
2014-09-07 10:32 ` Ming Lei
2014-09-10 15:18 ` Paolo Bonzini
2014-09-10 15:21 ` Ming Lei
2014-09-07 11:41 ` Michael S. Tsirkin
2014-09-07 18:47 ` Christoph Hellwig
2014-09-08 8:18 ` Michael S. Tsirkin
2014-09-08 20:15 ` Christoph Hellwig
2014-09-10 16:43 ` Michael S. Tsirkin
2014-09-08 16:21 ` Paolo Bonzini
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