On 09/15/2015 01:10 AM, Yuanhan Liu wrote: > From: Changchun Ouyang <changchun.ouy...@intel.com> > > This patch is initially based a patch from Nikolay Nikolaev. > > Here is the latest version for adding vhost-user multiple queue support, > by creating a nc and vhost_net pair for each queue.
The phrase "Here is the latest version" doesn't make much sense in the
long term in git (that is, a year from now, we won't care how many
preliminary versions there were, just about the version that got
committed; and if anything in git changes after that point, it is no
longer the latest version).
>
> Qemu exits if find that the backend can't support number of requested
> queues(by providing queues=# option). The max number is queried by a
space before ( in English.
> new message, VHOST_USER_GET_QUEUE_NUM, and is sent only when protocol
> feature VHOST_USER_PROTOCOL_F_MQ is present first.
>
> The max queue check is done at vhost-user initiation stage. We initiate
> one queue first, which, in the meantime, also gets the max_queues the
> backend supports.
>
> In older version, it was reported that some messages are sent more times
> than necessary. Here we came an agreement with Michael that we could
> categorize vhost user messages to 2 types: none-vring specific messages,
s/none/non/
> which should be sent only once, and vring specific messages, which should
> be sent per queue.
>
> Here I introduced a helper function vhost_user_one_time_request(), which
> lists following messages as none-vring specific messages:
s/none/non/
>
> VHOST_USER_GET_FEATURES
> VHOST_USER_SET_FEATURES
> VHOST_USER_GET_PROTOCOL_FEATURES
> VHOST_USER_SET_PROTOCOL_FEATURES
> VHOST_USER_SET_OWNER
> VHOST_USER_RESET_DEVICE
> VHOST_USER_SET_MEM_TABLE
> VHOST_USER_GET_QUEUE_NUM
>
> For above messages, we simply ignore them when they are not sent the first
> time.
>
Up to here is mostly fine for the commit message. Meanwhile...
> v9: per suggested by Jason Wang, we could invoke qemu_chr_add_handlers()
> once only, and invoke qemu_find_net_clients_except() at the handler
> to gather all related ncs, for initiating all queues. Which addresses
> a hidden bug in older verion in a more QEMU-like way.
>
> v8: set net->dev.vq_index correctly inside vhost_net_init() based on the
> value from net->nc->queue_index.
...this chunk here is useful only on the mailing list, and not in git,
and therefore, should appear...
>
> Signed-off-by: Nikolay Nikolaev <n.nikol...@virtualopensystems.com>
> Signed-off-by: Changchun Ouyang <changchun.ouy...@intel.com>
> Signed-off-by: Yuanhan Liu <yuanhan....@linux.intel.com>
> ---
...here, after the --- separator.
> docs/specs/vhost-user.txt | 13 +++++
> hw/net/vhost_net.c | 10 ++--
> hw/virtio/vhost-user.c | 26 +++++++++
> hw/virtio/vhost.c | 5 +-
> net/vhost-user.c | 146
> +++++++++++++++++++++++++++++++++-------------
> qapi-schema.json | 6 +-
> qemu-options.hx | 5 +-
> 7 files changed, 161 insertions(+), 50 deletions(-)
>
> diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
> index 43db9b4..acf5708 100644
> --- a/docs/specs/vhost-user.txt
> +++ b/docs/specs/vhost-user.txt
> @@ -135,6 +135,19 @@ As older slaves don't support negotiating protocol
> features,
> a feature bit was dedicated for this purpose:
> #define VHOST_USER_F_PROTOCOL_FEATURES 30
>
> +Multiple queue support
> +-------------------
Nit: the ---- line looks better when it is as long as the text it is
highlighting (3 bytes more)
> +Multiple queue is treated as a protocol extension, hence the slave has to
> +implement protocol features first. Multiple queues is supported only when
Sounds awkward. Either "Multiple queues are supported" or "The multiple
queues feature is supported"
> +the protocol feature VHOST_USER_PROTOCOL_F_MQ(bit 0) is set.
space before ( in English.
> +
> +The max number of queues the slave supports can be queried with message
> +VHOST_USER_GET_PROTOCOL_FEATURES. Master should stop when the number of
> +requested queues is bigger than that.
> +
> +As all queues share one connection, the master uses a unique index for each
> +queue in the sent message to identify a specified queue.
> +
> Message types
> -------------
>
> @@ -207,6 +224,15 @@ static int vhost_user_call(struct vhost_dev *dev,
> unsigned long int request,
> msg_request = request;
> }
>
> + /*
> + * For none-vring specific requests, like VHOST_USER_GET_FEATURES,
s/none/non/
> + * we just need send it once in the first time. For later such
> + * request, we just ignore it.
> + */
> + if (vhost_user_one_time_request(msg_request) && dev->vq_index != 0) {
> + return 0;
> + }
> +++ b/qapi-schema.json
> @@ -2480,12 +2480,16 @@
> #
> # @vhostforce: #optional vhost on for non-MSIX virtio guests (default:
> false).
> #
> +# @queues: #optional number of queues to be created for multiqueue vhost-user
> +# (default: 1) (Since 2.5)
> +#
> # Since 2.1
> ##
> { 'struct': 'NetdevVhostUserOptions',
> 'data': {
> 'chardev': 'str',
> - '*vhostforce': 'bool' } }
> + '*vhostforce': 'bool',
> + '*queues': 'int' } }
Interface looks okay.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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