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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Alvaro Karsz <alvaro.karsz@solid-run.com>
Cc: "xuanzhuo@linux.alibaba.com" <xuanzhuo@linux.alibaba.com>,
	"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: [RFC PATCH net 2/3] virtio-net: allow usage of vrings smaller than MAX_SKB_FRAGS + 2
Date: Fri, 2 Jun 2023 07:30:32 -0400	[thread overview]
Message-ID: <20230602072957-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <AM0PR04MB4723AA2ABCE91928BE735DEBD46E9@AM0PR04MB4723.eurprd04.prod.outlook.com>

On Mon, May 01, 2023 at 11:59:42AM +0000, Alvaro Karsz wrote:
> > First up to 4k should not be a problem. Even jumbo frames e.g. 9k
> > is highly likely to succeed. And a probe time which is often boot
> > even 64k isn't a problem ...
> > 
> > Hmm. We could allocate large buffers at probe time. Reuse them and
> > copy data over.
> > 
> > IOW reusing  GOOD_COPY_LEN flow for this case.  Not yet sure how I feel
> > about this. OTOH it removes the need for the whole feature blocking
> > approach, does it not?
> > WDYT?
> > 
> 
> It could work..
> 
> In order to remove completely the feature blocking approach, we'll need to let the control commands fail (as you mentioned in the other patch).
> I'm not sure I like it, it means many warnings from virtnet..
> And it means accepting features that we know for sure that are not going to work.
>

Well they will work yes? just with an extra copy.

-- 
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: "jasowang@redhat.com" <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>,
	"xuanzhuo@linux.alibaba.com" <xuanzhuo@linux.alibaba.com>
Subject: Re: [RFC PATCH net 2/3] virtio-net: allow usage of vrings smaller than MAX_SKB_FRAGS + 2
Date: Fri, 2 Jun 2023 07:30:32 -0400	[thread overview]
Message-ID: <20230602072957-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <AM0PR04MB4723AA2ABCE91928BE735DEBD46E9@AM0PR04MB4723.eurprd04.prod.outlook.com>

On Mon, May 01, 2023 at 11:59:42AM +0000, Alvaro Karsz wrote:
> > First up to 4k should not be a problem. Even jumbo frames e.g. 9k
> > is highly likely to succeed. And a probe time which is often boot
> > even 64k isn't a problem ...
> > 
> > Hmm. We could allocate large buffers at probe time. Reuse them and
> > copy data over.
> > 
> > IOW reusing  GOOD_COPY_LEN flow for this case.  Not yet sure how I feel
> > about this. OTOH it removes the need for the whole feature blocking
> > approach, does it not?
> > WDYT?
> > 
> 
> It could work..
> 
> In order to remove completely the feature blocking approach, we'll need to let the control commands fail (as you mentioned in the other patch).
> I'm not sure I like it, it means many warnings from virtnet..
> And it means accepting features that we know for sure that are not going to work.
>

Well they will work yes? just with an extra copy.

-- 
MST 


  reply	other threads:[~2023-06-02 11:30 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-30 13:15 [RFC PATCH net 0/3] virtio-net: allow usage of small vrings Alvaro Karsz
2023-04-30 13:15 ` Alvaro Karsz
2023-04-30 13:15 ` [RFC PATCH net 1/3] virtio: re-negotiate features if probe fails and features are blocked Alvaro Karsz
2023-04-30 13:15   ` Alvaro Karsz
2023-04-30 13:27   ` Michael S. Tsirkin
2023-04-30 13:27     ` Michael S. Tsirkin
2023-04-30 18:18     ` Alvaro Karsz
2023-04-30 18:18       ` Alvaro Karsz
2023-04-30 13:15 ` [RFC PATCH net 2/3] virtio-net: allow usage of vrings smaller than MAX_SKB_FRAGS + 2 Alvaro Karsz
2023-04-30 13:15   ` Alvaro Karsz
2023-04-30 14:05   ` Michael S. Tsirkin
2023-04-30 14:05     ` Michael S. Tsirkin
2023-04-30 18:54     ` Alvaro Karsz
2023-04-30 18:54       ` Alvaro Karsz
2023-05-01 10:20       ` Michael S. Tsirkin
2023-05-01 10:20         ` Michael S. Tsirkin
2023-05-01 11:59         ` Alvaro Karsz
2023-05-01 11:59           ` Alvaro Karsz
2023-06-02 11:30           ` Michael S. Tsirkin [this message]
2023-06-02 11:30             ` Michael S. Tsirkin
2023-04-30 13:15 ` [RFC PATCH net 3/3] virtio-net: block ethtool from converting a ring to a small ring Alvaro Karsz
2023-04-30 13:15   ` Alvaro Karsz
2023-04-30 14:06 ` [RFC PATCH net 0/3] virtio-net: allow usage of small vrings Michael S. Tsirkin
2023-04-30 14:06   ` Michael S. Tsirkin
2023-04-30 18:15   ` Alvaro Karsz
2023-04-30 18:15     ` Alvaro Karsz
2023-05-01 10:27     ` Michael S. Tsirkin
2023-05-01 10:27       ` Michael S. Tsirkin
2023-05-01 11:41       ` Alvaro Karsz
2023-05-01 11:41         ` Alvaro Karsz
2023-06-02 11:29         ` Michael S. Tsirkin
2023-06-02 11:29           ` Michael S. Tsirkin
2023-06-17  7:44 ` Michael S. Tsirkin
2023-06-17  7:44   ` Michael S. Tsirkin

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