From: Daniel Borkmann <daniel@iogearbox•net>
To: Jakub Kicinski <kubakici@wp•pl>
Cc: Yuval Mintz <Yuval.Mintz@cavium•com>,
davem@davemloft•net, netdev@vger•kernel.org,
alexei.starovoitov@gmail•com
Subject: Re: [PATCH v2 net-next 10/11] qede: Add basic XDP support
Date: Tue, 29 Nov 2016 19:28:56 +0100 [thread overview]
Message-ID: <583DC8E8.1060408@iogearbox.net> (raw)
In-Reply-To: <20161129171020.6b8b552d@jkicinski-Precision-T1700>
On 11/29/2016 06:10 PM, Jakub Kicinski wrote:
> On Tue, 29 Nov 2016 16:48:50 +0100, Daniel Borkmann wrote:
>> On 11/29/2016 03:47 PM, Yuval Mintz wrote:
>>> Add support for the ndo_xdp callback. This patch would support XDP_PASS,
>>> XDP_DROP and XDP_ABORTED commands.
>>>
>>> This also adds a per Rx queue statistic which counts number of packets
>>> which didn't reach the stack [due to XDP].
>>>
>>> Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium•com>
>> [...]
>>> @@ -1560,6 +1593,7 @@ static int qede_rx_process_cqe(struct qede_dev *edev,
>>> struct qede_fastpath *fp,
>>> struct qede_rx_queue *rxq)
>>> {
>>> + struct bpf_prog *xdp_prog = READ_ONCE(rxq->xdp_prog);
>>> struct eth_fast_path_rx_reg_cqe *fp_cqe;
>>> u16 len, pad, bd_cons_idx, parse_flag;
>>> enum eth_rx_cqe_type cqe_type;
>>> @@ -1596,6 +1630,11 @@ static int qede_rx_process_cqe(struct qede_dev *edev,
>>> len = le16_to_cpu(fp_cqe->len_on_first_bd);
>>> pad = fp_cqe->placement_offset;
>>>
>>> + /* Run eBPF program if one is attached */
>>> + if (xdp_prog)
>>> + if (!qede_rx_xdp(edev, fp, rxq, xdp_prog, bd, fp_cqe))
>>> + return 1;
>>> +
>>
>> You also need to wrap this under rcu_read_lock() (at least I haven't seen
>> it in your patches) for same reasons as stated in 326fe02d1ed6 ("net/mlx4_en:
>> protect ring->xdp_prog with rcu_read_lock"), as otherwise xdp_prog could
>> disappear underneath you. mlx4 and nfp does it correctly, looks like mlx5
>> doesn't.
>
> My understanding was that Yuval is always doing full stop()/start() so
> there should be no RX packets in flight while the XDP prog is being
> changed. But thinking about it again, perhaps is worth adding the
Ohh, true, thanks for pointing this out. I guess I got confused by
the READ_ONCE() then.
> optimization to forego the full qede_reload() in qede_xdp_set() if there
> is a program already loaded and just do the xchg()+put() (and add RCU
> protection on the fast path)?
Would be worth it as a follow-up later on, yes.
next prev parent reply other threads:[~2016-11-29 18:48 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-29 14:46 [PATCH v2 net-next 00/11] qed*: Add XDP support Yuval Mintz
2016-11-29 14:47 ` [PATCH v2 net-next 01/11] qede: Optimize aggregation information size Yuval Mintz
2016-11-29 14:47 ` [PATCH v2 net-next 02/11] qed: Optimize qed_chain datapath usage Yuval Mintz
2016-11-29 14:47 ` [PATCH v2 net-next 03/11] qede: Remove 'num_tc' Yuval Mintz
2016-11-29 14:47 ` [PATCH v2 net-next 04/11] qede: Refactor statistics gathering Yuval Mintz
2016-11-29 14:47 ` [PATCH v2 net-next 05/11] qede: Refactor data-path Rx flow Yuval Mintz
2016-11-29 14:47 ` [PATCH v2 net-next 06/11] qede: Revise state locking scheme Yuval Mintz
2016-11-29 14:47 ` [PATCH v2 net-next 07/11] qed*: Handle-based L2-queues Yuval Mintz
2016-11-29 14:47 ` [PATCH v2 net-next 08/11] qede: Don't check netdevice for rx-hash Yuval Mintz
2016-11-29 14:47 ` [PATCH v2 net-next 09/11] qede: Better utilize the qede_[rt]x_queue Yuval Mintz
2016-11-29 14:47 ` [PATCH v2 net-next 10/11] qede: Add basic XDP support Yuval Mintz
2016-11-29 15:48 ` Daniel Borkmann
2016-11-29 17:10 ` Jakub Kicinski
2016-11-29 17:51 ` Mintz, Yuval
2016-11-29 18:42 ` Daniel Borkmann
2016-11-29 18:28 ` Daniel Borkmann [this message]
2016-11-29 14:47 ` [PATCH v2 net-next 11/11] qede: Add support for XDP_TX Yuval Mintz
2016-11-30 19:32 ` [PATCH v2 net-next 00/11] qed*: Add XDP support David Miller
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