From: "Michael S. Tsirkin" <mst@redhat.com>
To: Alvaro Karsz <alvaro.karsz@solid-run.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
"edumazet@google.com" <edumazet@google.com>,
"kuba@kernel.org" <kuba@kernel.org>,
"pabeni@redhat.com" <pabeni@redhat.com>,
"davem@davemloft.net" <davem@davemloft.net>
Subject: Re: [PATCH net] virtio-net: reject small vring sizes
Date: Mon, 17 Apr 2023 07:57:24 -0400 [thread overview]
Message-ID: <20230417075645-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <AM0PR04MB4723FA4F0FFEBD25903E3344D49C9@AM0PR04MB4723.eurprd04.prod.outlook.com>
On Mon, Apr 17, 2023 at 11:51:22AM +0000, Alvaro Karsz wrote:
> > > I see your point.
> > > Regardless, we'll need to fail probe in some cases.
> > > ring size of 1 for example (if I'm not mistaken)
> >
> > Hmm. We can make it work if we increase hard header size, then
> > there will always be room for vnet header.
> >
> > > control vq even needs a bigger ring.
> >
> > Why does it?
>
> At the moment, most of the commands chain 3 descriptors:
> 1 - class + command
> 2 - command specific
> 3 - ack
>
> We could merge 1 and 2 into a single one, both are read only for the device, so I take it back, it won't need a bigger ring.
> But it will need 2 descriptors at least(1 read only for the device and 1 write only for the device), so we still need to fail probe sometimes.
>
Yes that makes sense, it's architetural. We can disable ctrl vq though.
--
MST
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WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Alvaro Karsz <alvaro.karsz@solid-run.com>
Cc: Jason Wang <jasowang@redhat.com>,
"davem@davemloft.net" <davem@davemloft.net>,
"edumazet@google.com" <edumazet@google.com>,
"kuba@kernel.org" <kuba@kernel.org>,
"pabeni@redhat.com" <pabeni@redhat.com>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH net] virtio-net: reject small vring sizes
Date: Mon, 17 Apr 2023 07:57:24 -0400 [thread overview]
Message-ID: <20230417075645-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <AM0PR04MB4723FA4F0FFEBD25903E3344D49C9@AM0PR04MB4723.eurprd04.prod.outlook.com>
On Mon, Apr 17, 2023 at 11:51:22AM +0000, Alvaro Karsz wrote:
> > > I see your point.
> > > Regardless, we'll need to fail probe in some cases.
> > > ring size of 1 for example (if I'm not mistaken)
> >
> > Hmm. We can make it work if we increase hard header size, then
> > there will always be room for vnet header.
> >
> > > control vq even needs a bigger ring.
> >
> > Why does it?
>
> At the moment, most of the commands chain 3 descriptors:
> 1 - class + command
> 2 - command specific
> 3 - ack
>
> We could merge 1 and 2 into a single one, both are read only for the device, so I take it back, it won't need a bigger ring.
> But it will need 2 descriptors at least(1 read only for the device and 1 write only for the device), so we still need to fail probe sometimes.
>
Yes that makes sense, it's architetural. We can disable ctrl vq though.
--
MST
next prev parent reply other threads:[~2023-04-17 11:57 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-16 7:46 [PATCH net] virtio-net: reject small vring sizes Alvaro Karsz
2023-04-16 7:46 ` Alvaro Karsz
2023-04-16 16:54 ` Alvaro Karsz
2023-04-16 16:54 ` Alvaro Karsz
2023-04-16 20:45 ` Michael S. Tsirkin
2023-04-16 20:45 ` Michael S. Tsirkin
2023-04-17 3:24 ` Jason Wang
2023-04-17 3:24 ` Jason Wang
2023-04-17 6:20 ` Michael S. Tsirkin
2023-04-17 6:20 ` Michael S. Tsirkin
2023-04-17 6:38 ` Alvaro Karsz
2023-04-17 6:38 ` Alvaro Karsz
2023-04-17 6:41 ` Michael S. Tsirkin
2023-04-17 6:41 ` Michael S. Tsirkin
2023-04-17 7:03 ` Alvaro Karsz
2023-04-17 7:03 ` Alvaro Karsz
2023-04-17 7:10 ` Michael S. Tsirkin
2023-04-17 7:10 ` Michael S. Tsirkin
2023-04-17 7:33 ` Alvaro Karsz
2023-04-17 7:33 ` Alvaro Karsz
2023-04-17 9:20 ` Michael S. Tsirkin
2023-04-17 9:20 ` Michael S. Tsirkin
2023-04-17 10:04 ` Alvaro Karsz
2023-04-17 10:04 ` Alvaro Karsz
2023-04-17 11:40 ` Michael S. Tsirkin
2023-04-17 11:40 ` Michael S. Tsirkin
2023-04-17 11:51 ` Alvaro Karsz
2023-04-17 11:51 ` Alvaro Karsz
2023-04-17 11:57 ` Michael S. Tsirkin [this message]
2023-04-17 11:57 ` Michael S. Tsirkin
2023-04-23 6:51 ` Alvaro Karsz
2023-04-23 6:51 ` Alvaro Karsz
2023-04-23 7:19 ` Michael S. Tsirkin
2023-04-23 7:19 ` Michael S. Tsirkin
2023-04-23 7:52 ` Alvaro Karsz
2023-04-23 7:52 ` Alvaro Karsz
2023-04-23 11:06 ` Michael S. Tsirkin
2023-04-23 11:06 ` Michael S. Tsirkin
2023-04-23 12:28 ` Alvaro Karsz
2023-04-23 12:28 ` Alvaro Karsz
2023-04-23 20:17 ` Michael S. Tsirkin
2023-04-23 20:17 ` Michael S. Tsirkin
2023-04-25 8:34 ` Michael S. Tsirkin
2023-04-25 8:34 ` Michael S. Tsirkin
2023-04-25 9:41 ` Alvaro Karsz
2023-04-25 9:41 ` Alvaro Karsz
2023-04-25 11:11 ` Alvaro Karsz
2023-04-25 11:11 ` Alvaro Karsz
2023-04-25 12:33 ` Michael S. Tsirkin
2023-04-25 12:33 ` Michael S. Tsirkin
2023-04-25 12:31 ` Michael S. Tsirkin
2023-04-25 12:31 ` Michael S. Tsirkin
2023-04-25 13:02 ` Alvaro Karsz
2023-04-25 13:02 ` Alvaro Karsz
2023-04-25 13:08 ` Michael S. Tsirkin
2023-04-25 13:08 ` Michael S. Tsirkin
2023-04-23 8:01 ` Alvaro Karsz
2023-04-23 8:01 ` Alvaro Karsz
2023-04-23 11:08 ` Michael S. Tsirkin
2023-04-23 11:08 ` Michael S. Tsirkin
2023-04-17 6:44 ` Xuan Zhuo
2023-04-17 6:44 ` Xuan Zhuo
2023-04-17 7:07 ` Alvaro Karsz
2023-04-17 7:07 ` Alvaro Karsz
2023-04-17 7:11 ` Michael S. Tsirkin
2023-04-17 7:11 ` Michael S. Tsirkin
2023-04-16 20:38 ` Michael S. Tsirkin
2023-04-16 20:38 ` Michael S. Tsirkin
2023-04-17 6:43 ` Alvaro Karsz
2023-04-17 6:43 ` Alvaro Karsz
2023-04-23 11:09 ` Michael S. Tsirkin
2023-04-23 11:09 ` Michael S. Tsirkin
2023-04-17 1:53 ` Xuan Zhuo
2023-04-17 1:53 ` Xuan Zhuo
2023-04-17 6:47 ` Alvaro Karsz
2023-04-17 6:47 ` Alvaro Karsz
2023-04-17 3:34 ` Xuan Zhuo
2023-04-17 3:34 ` Xuan Zhuo
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