[Qemu-devel] [PATCH] block: add block_set_io_throttle virtio-blk-pci QMP example

[Qemu-devel] [PATCH] block: add block_set_io_throttle virtio-blk-pci QMP example

[Stefan Hajnoczi]

The block_set_io_throttle command can look up BlockBackends by the
attached qdev device ID.  virtio-blk-pci is a special case because the
actual VirtIOBlock device is the "/virtio-backend" child of the PCI
adapter device.

Add a QMP schema example so clients will know how to use
block_set_io_throttle on the virtio-blk-pci device.

The alternative is to implement some sort of aliasing for qmp_get_blk()
but that is likely to cause confusion and could break future use cases.
Let's not go there.

Cc: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 qapi/block-core.json | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/qapi/block-core.json b/qapi/block-core.json
index e94a6881b2..4e84cf29db 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1799,6 +1799,24 @@
 # Example:
 #
 # -> { "execute": "block_set_io_throttle",
+#      "arguments": { "id": "virtio-blk-pci0/virtio-backend",
+#                     "bps": 0,
+#                     "bps_rd": 0,
+#                     "bps_wr": 0,
+#                     "iops": 512,
+#                     "iops_rd": 0,
+#                     "iops_wr": 0,
+#                     "bps_max": 0,
+#                     "bps_rd_max": 0,
+#                     "bps_wr_max": 0,
+#                     "iops_max": 0,
+#                     "iops_rd_max": 0,
+#                     "iops_wr_max": 0,
+#                     "bps_max_length": 0,
+#                     "iops_size": 0 } }
+# <- { "return": {} }
+#
+# -> { "execute": "block_set_io_throttle",
 #      "arguments": { "id": "ide0-1-0",
 #                     "bps": 1000000,
 #                     "bps_rd": 0,
-- 
2.14.3

Re: [Qemu-devel] [Qemu-block] [PATCH] block: add block_set_io_throttle virtio-blk-pci QMP example

[Alberto Garcia]

On Wed 17 Jan 2018 10:07:00 AM CET, Stefan Hajnoczi wrote:
> The block_set_io_throttle command can look up BlockBackends by the
> attached qdev device ID.  virtio-blk-pci is a special case because the
> actual VirtIOBlock device is the "/virtio-backend" child of the PCI
> adapter device.
>
> Add a QMP schema example so clients will know how to use
> block_set_io_throttle on the virtio-blk-pci device.
>
> The alternative is to implement some sort of aliasing for qmp_get_blk()
> but that is likely to cause confusion and could break future use cases.
> Let's not go there.
>
> Cc: Kevin Wolf <kwolf@redhat.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Reviewed-by: Alberto Garcia <berto@igalia.com>

Berto

Re: [Qemu-devel] [PATCH] block: add block_set_io_throttle virtio-blk-pci QMP example

[Stefan Hajnoczi]

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On Wed, Jan 17, 2018 at 09:07:00AM +0000, Stefan Hajnoczi wrote:
> The block_set_io_throttle command can look up BlockBackends by the
> attached qdev device ID.  virtio-blk-pci is a special case because the
> actual VirtIOBlock device is the "/virtio-backend" child of the PCI
> adapter device.
> 
> Add a QMP schema example so clients will know how to use
> block_set_io_throttle on the virtio-blk-pci device.
> 
> The alternative is to implement some sort of aliasing for qmp_get_blk()
> but that is likely to cause confusion and could break future use cases.
> Let's not go there.
> 
> Cc: Kevin Wolf <kwolf@redhat.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  qapi/block-core.json | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)

Thanks, applied to my block tree:
https://github.com/stefanha/qemu/commits/block

Stefan

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