From: David Laight <David.Laight@ACULAB.COM>
To: 'Brenden Blanco' <bblanco@plumgrid.com>,
"davem@davemloft.net" <davem@davemloft.net>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>,
Saeed Mahameed <saeedm@dev.mellanox.co.il>,
Martin KaFai Lau <kafai@fb.com>,
"Jesper Dangaard Brouer" <brouer@redhat.com>,
Ari Saha <as754m@att.com>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Or Gerlitz <gerlitz.or@gmail.com>,
"john.fastabend@gmail.com" <john.fastabend@gmail.com>,
"hannes@stressinduktion.org" <hannes@stressinduktion.org>,
Thomas Graf <tgraf@suug.ch>, Tom Herbert <tom@herbertland.com>,
Daniel Borkmann <daniel@iogearbox.net>
Subject: RE: [PATCH v8 04/11] net/mlx4_en: add support for fast rx drop bpf program
Date: Wed, 13 Jul 2016 11:27:23 +0000 [thread overview]
Message-ID: <063D6719AE5E284EB5DD2968C1650D6D5F4F6ED7@AcuExch.aculab.com> (raw)
In-Reply-To: <1468309894-26258-5-git-send-email-bblanco@plumgrid.com>
From: Brenden Blanco
> Sent: 12 July 2016 08:51
> Add support for the BPF_PROG_TYPE_XDP hook in mlx4 driver.
>
> In tc/socket bpf programs, helpers linearize skb fragments as needed
> when the program touches the packet data. However, in the pursuit of
> speed, XDP programs will not be allowed to use these slower functions,
> especially if it involves allocating an skb.
>
> Therefore, disallow MTU settings that would produce a multi-fragment
> packet that XDP programs would fail to access. Future enhancements could
> be done to increase the allowable MTU.
Maybe I'm misunderstanding what is going on here...
But what has the MTU to do with how skb are fragmented?
If the skb come from a reasonably written USB ethernet interface they could
easily have arbitrary fragment boundaries (the frames get packed into USB
buffers).
Outbound skb can also have fragments depending on how they are generated.
David
next prev parent reply other threads:[~2016-07-13 11:31 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-12 7:51 [PATCH v8 00/11] Add driver bpf hook for early packet drop and forwarding Brenden Blanco
2016-07-12 7:51 ` [PATCH v8 01/11] bpf: add XDP prog type for early driver filter Brenden Blanco
2016-07-12 13:14 ` Jesper Dangaard Brouer
2016-07-12 14:52 ` Tom Herbert
2016-07-12 16:08 ` Jakub Kicinski
2016-07-13 4:14 ` Alexei Starovoitov
2016-07-12 7:51 ` [PATCH v8 02/11] net: add ndo to setup/query xdp prog in adapter rx Brenden Blanco
2016-07-12 7:51 ` [PATCH v8 03/11] rtnl: add option for setting link xdp prog Brenden Blanco
2016-07-12 7:51 ` [PATCH v8 04/11] net/mlx4_en: add support for fast rx drop bpf program Brenden Blanco
2016-07-12 12:02 ` Tariq Toukan
2016-07-13 11:27 ` David Laight [this message]
2016-07-13 14:08 ` Brenden Blanco
2016-07-14 7:25 ` Jesper Dangaard Brouer
2016-07-15 3:30 ` Alexei Starovoitov
2016-07-15 8:21 ` Jesper Dangaard Brouer
2016-07-15 16:56 ` Alexei Starovoitov
2016-07-15 16:18 ` Tom Herbert
2016-07-15 16:47 ` Alexei Starovoitov
2016-07-15 17:49 ` Tom Herbert
2016-07-18 9:10 ` Thomas Graf
2016-07-18 11:39 ` Tom Herbert
2016-07-18 12:48 ` Thomas Graf
2016-07-18 13:07 ` Tom Herbert
2016-07-19 2:45 ` Alexei Starovoitov
2016-07-18 19:03 ` Brenden Blanco
2016-07-15 19:09 ` Jesper Dangaard Brouer
2016-07-18 4:01 ` Alexei Starovoitov
2016-07-18 8:35 ` Daniel Borkmann
2016-07-15 18:08 ` Tom Herbert
2016-07-15 18:45 ` Jesper Dangaard Brouer
2016-07-12 7:51 ` [PATCH v8 05/11] Add sample for adding simple drop program to link Brenden Blanco
2016-07-12 7:51 ` [PATCH v8 06/11] net/mlx4_en: add page recycle to prepare rx ring for tx support Brenden Blanco
2016-07-12 12:09 ` Tariq Toukan
2016-07-12 21:18 ` David Miller
2016-07-13 0:54 ` Brenden Blanco
2016-07-13 7:17 ` Tariq Toukan
2016-07-13 15:40 ` Brenden Blanco
2016-07-15 21:52 ` Brenden Blanco
[not found] ` <6d638467-eea6-d3e1-6984-88a1198ef303@gmail.com>
2016-07-19 17:41 ` Brenden Blanco
2016-07-12 7:51 ` [PATCH v8 07/11] bpf: add XDP_TX xdp_action for direct forwarding Brenden Blanco
2016-07-12 7:51 ` [PATCH v8 08/11] net/mlx4_en: break out tx_desc write into separate function Brenden Blanco
2016-07-12 12:16 ` Tariq Toukan
2016-07-12 7:51 ` [PATCH v8 09/11] net/mlx4_en: add xdp forwarding and data write support Brenden Blanco
2016-07-12 7:51 ` [PATCH v8 10/11] bpf: enable direct packet data write for xdp progs Brenden Blanco
2016-07-12 7:51 ` [PATCH v8 11/11] bpf: add sample for xdp forwarding and rewrite Brenden Blanco
2016-07-12 14:38 ` [PATCH v8 00/11] Add driver bpf hook for early packet drop and forwarding Tariq Toukan
2016-07-13 15:00 ` Tariq Toukan
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