From: Herbert Xu <herbert@gondor.hengli.com.au>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
Jan Kiszka <jan.kiszka@siemens.com>,
"David S. Miller" <davem@davemloft.net>,
Paul Moore <paul.moore@hp.com>,
David Woodhouse <David.Woodhouse@intel.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
qemu-devel <qemu-devel@nongnu.org>
Subject: Re: [PATCH] tun: orphan an skb on tx
Date: Wed, 14 Apr 2010 08:58:22 +0800 [thread overview]
Message-ID: <20100414005822.GD18044@gondor.apana.org.au> (raw)
In-Reply-To: <1271183463.16881.545.camel@edumazet-laptop>
On Tue, Apr 13, 2010 at 08:31:03PM +0200, Eric Dumazet wrote:
>
> Herbert Acked your patch, so I guess its OK, but I think it can be
> dangerous.
The tun socket accounting was never designed to stop it from
flooding another tun interface. It's there to stop it from
transmitting above a destination interface TX bandwidth and
cause unnecessary packet drops. It also limits the total amount
of kernel memory that can be pinned down by a single tun interface.
In this case, all we're doing is shifting the accounting from the
"hardware" queue to the qdisc queue.
So your ability to flood a tun interface is essentially unchanged.
BTW we do the same thing in a number of hardware drivers, as well
as virtio-net.
Cheers,
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
WARNING: multiple messages have this Message-ID (diff)
From: Herbert Xu <herbert@gondor.apana.org.au>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
Jan Kiszka <jan.kiszka@siemens.com>,
"David S. Miller" <davem@davemloft.net>,
Paul Moore <paul.moore@hp.com>,
David Woodhouse <David.Woodhouse@intel.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
qemu-devel <qemu-devel@nongnu.org>
Subject: Re: [PATCH] tun: orphan an skb on tx
Date: Wed, 14 Apr 2010 08:58:22 +0800 [thread overview]
Message-ID: <20100414005822.GD18044@gondor.apana.org.au> (raw)
In-Reply-To: <1271183463.16881.545.camel@edumazet-laptop>
On Tue, Apr 13, 2010 at 08:31:03PM +0200, Eric Dumazet wrote:
>
> Herbert Acked your patch, so I guess its OK, but I think it can be
> dangerous.
The tun socket accounting was never designed to stop it from
flooding another tun interface. It's there to stop it from
transmitting above a destination interface TX bandwidth and
cause unnecessary packet drops. It also limits the total amount
of kernel memory that can be pinned down by a single tun interface.
In this case, all we're doing is shifting the accounting from the
"hardware" queue to the qdisc queue.
So your ability to flood a tun interface is essentially unchanged.
BTW we do the same thing in a number of hardware drivers, as well
as virtio-net.
Cheers,
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
WARNING: multiple messages have this Message-ID (diff)
From: Herbert Xu <herbert@gondor.apana.org.au>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Paul Moore <paul.moore@hp.com>,
David Woodhouse <David.Woodhouse@intel.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Jan Kiszka <jan.kiszka@siemens.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
qemu-devel <qemu-devel@nongnu.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"David S. Miller" <davem@davemloft.net>
Subject: [Qemu-devel] Re: [PATCH] tun: orphan an skb on tx
Date: Wed, 14 Apr 2010 08:58:22 +0800 [thread overview]
Message-ID: <20100414005822.GD18044@gondor.apana.org.au> (raw)
In-Reply-To: <1271183463.16881.545.camel@edumazet-laptop>
On Tue, Apr 13, 2010 at 08:31:03PM +0200, Eric Dumazet wrote:
>
> Herbert Acked your patch, so I guess its OK, but I think it can be
> dangerous.
The tun socket accounting was never designed to stop it from
flooding another tun interface. It's there to stop it from
transmitting above a destination interface TX bandwidth and
cause unnecessary packet drops. It also limits the total amount
of kernel memory that can be pinned down by a single tun interface.
In this case, all we're doing is shifting the accounting from the
"hardware" queue to the qdisc queue.
So your ability to flood a tun interface is essentially unchanged.
BTW we do the same thing in a number of hardware drivers, as well
as virtio-net.
Cheers,
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
next prev parent reply other threads:[~2010-04-14 0:58 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-13 14:59 [PATCH] tun: orphan an skb on tx Michael S. Tsirkin
2010-04-13 14:59 ` [Qemu-devel] " Michael S. Tsirkin
2010-04-13 15:12 ` Herbert Xu
2010-04-13 15:12 ` [Qemu-devel] " Herbert Xu
2010-04-13 15:12 ` Herbert Xu
2010-04-13 15:36 ` Jan Kiszka
2010-04-13 15:36 ` [Qemu-devel] " Jan Kiszka
2010-04-13 16:40 ` Eric Dumazet
2010-04-13 16:40 ` [Qemu-devel] " Eric Dumazet
2010-04-13 16:52 ` Jan Kiszka
2010-04-13 16:52 ` [Qemu-devel] " Jan Kiszka
2010-04-13 17:39 ` Michael S. Tsirkin
2010-04-13 17:39 ` [Qemu-devel] " Michael S. Tsirkin
2010-04-13 18:31 ` Eric Dumazet
2010-04-13 18:31 ` [Qemu-devel] " Eric Dumazet
2010-04-13 20:25 ` Michael S. Tsirkin
2010-04-13 20:25 ` [Qemu-devel] " Michael S. Tsirkin
2010-04-13 20:38 ` Eric Dumazet
2010-04-13 20:38 ` [Qemu-devel] " Eric Dumazet
2010-04-13 20:43 ` Michael S. Tsirkin
2010-04-13 20:43 ` [Qemu-devel] " Michael S. Tsirkin
2010-04-14 0:58 ` Herbert Xu [this message]
2010-04-14 0:58 ` Herbert Xu
2010-04-14 0:58 ` Herbert Xu
2010-04-14 11:55 ` David Miller
2010-04-14 11:55 ` [Qemu-devel] " David Miller
2010-04-14 11:55 ` David Miller
2015-02-01 11:20 ` David Woodhouse
2015-02-01 11:20 ` [Qemu-devel] " David Woodhouse
2015-02-01 12:26 ` Michael S. Tsirkin
2015-02-01 12:26 ` [Qemu-devel] " Michael S. Tsirkin
2015-02-01 13:33 ` David Woodhouse
2015-02-01 13:33 ` [Qemu-devel] " David Woodhouse
2015-02-01 20:19 ` David Miller
2015-02-01 20:19 ` [Qemu-devel] " David Miller
2015-02-01 21:29 ` David Woodhouse
2015-02-01 21:29 ` [Qemu-devel] " David Woodhouse
2015-02-02 5:07 ` David Miller
2015-02-02 5:07 ` [Qemu-devel] " David Miller
2015-02-02 5:07 ` David Miller
2015-02-02 7:27 ` David Woodhouse
2015-02-02 7:27 ` [Qemu-devel] " David Woodhouse
2015-02-02 8:24 ` Steffen Klassert
2015-02-02 8:24 ` [Qemu-devel] " Steffen Klassert
2015-02-02 15:30 ` David Woodhouse
2015-02-02 15:30 ` [Qemu-devel] " David Woodhouse
2015-02-02 15:23 ` Phil Sutter
2015-02-02 15:23 ` [Qemu-devel] " Phil Sutter
2015-02-02 15:47 ` David Woodhouse
2015-02-02 15:47 ` [Qemu-devel] " David Woodhouse
2015-02-04 0:19 ` David Miller
2015-02-04 0:19 ` [Qemu-devel] " David Miller
2015-02-04 6:35 ` David Woodhouse
2015-02-04 6:35 ` [Qemu-devel] " David Woodhouse
2021-06-25 15:56 ` Bringing the SSL VPN data path back in-kernel David Woodhouse
2010-04-21 11:35 ` [PATCH] tun: orphan an skb on tx Michael S. Tsirkin
2010-04-21 11:35 ` [Qemu-devel] " Michael S. Tsirkin
2010-04-21 11:46 ` Jan Kiszka
2010-04-21 11:46 ` [Qemu-devel] " Jan Kiszka
2010-04-21 11:45 ` Michael S. Tsirkin
2010-04-21 11:45 ` [Qemu-devel] " Michael S. Tsirkin
2010-04-21 19:16 ` [stable] " Greg KH
2010-04-21 19:16 ` [Qemu-devel] " Greg KH
2010-09-14 15:20 ` Michael S. Tsirkin
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