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From: Jesper Dangaard Brouer <jbrouer@redhat.com>
To: Kumar Kartikeya Dwivedi <memxor@gmail.com>, netdev@vger.kernel.org
Cc: "Toke Høiland-Jørgensen" <toke@redhat.com>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Andrii Nakryiko" <andrii@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	"Jakub Kicinski" <kuba@kernel.org>,
	"John Fastabend" <john.fastabend@gmail.com>,
	"Martin KaFai Lau" <kafai@fb.com>,
	"Eric Leblond" <eric@regit.org>,
	bpf@vger.kernel.org
Subject: Re: [PATCH net-next v6 3/5] bpf: cpumap: implement generic cpumap
Date: Fri, 2 Jul 2021 15:33:46 +0200	[thread overview]
Message-ID: <954f8592-285c-8d2b-db22-7d8818e0903c@redhat.com> (raw)
In-Reply-To: <20210702111825.491065-4-memxor@gmail.com>


On 02/07/2021 13.18, Kumar Kartikeya Dwivedi wrote:
> This change implements CPUMAP redirect support for generic XDP programs.
> The idea is to reuse the cpu map entry's queue that is used to push
> native xdp frames for redirecting skb to a different CPU. This will
> match native XDP behavior (in that RPS is invoked again for packet
> reinjected into networking stack).
>
> To be able to determine whether the incoming skb is from the driver or
> cpumap, we reuse skb->redirected bit that skips generic XDP processing
> when it is set. To always make use of this, CONFIG_NET_REDIRECT guard on
> it has been lifted and it is always available.
>
>  From the redirect side, we add the skb to ptr_ring with its lowest bit
> set to 1.  This should be safe as skb is not 1-byte aligned. This allows
> kthread to discern between xdp_frames and sk_buff. On consumption of the
> ptr_ring item, the lowest bit is unset.
>
> In the end, the skb is simply added to the list that kthread is anyway
> going to maintain for xdp_frames converted to skb, and then received
> again by using netif_receive_skb_list.
>
> Bulking optimization for generic cpumap is left as an exercise for a
> future patch for now.
>
> Since cpumap entry progs are now supported, also remove check in
> generic_xdp_install for the cpumap.
>
> Reviewed-by: Toke Høiland-Jørgensen<toke@redhat.com>
> Signed-off-by: Kumar Kartikeya Dwivedi<memxor@gmail.com>
> ---
>   include/linux/bpf.h    |   9 +++-
>   include/linux/skbuff.h |  10 +---
>   kernel/bpf/cpumap.c    | 116 ++++++++++++++++++++++++++++++++++-------
>   net/core/dev.c         |   3 +-
>   net/core/filter.c      |   6 ++-
>   5 files changed, 114 insertions(+), 30 deletions(-)


Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>



  reply	other threads:[~2021-07-02 13:33 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-02 11:18 [PATCH net-next v6 0/5] Generic XDP improvements Kumar Kartikeya Dwivedi
2021-07-02 11:18 ` [PATCH net-next v6 1/5] net: core: split out code to run generic XDP prog Kumar Kartikeya Dwivedi
2021-07-02 11:18 ` [PATCH net-next v6 2/5] bitops: add non-atomic bitops for pointers Kumar Kartikeya Dwivedi
2021-07-02 14:47   ` David Laight
2021-07-02 16:11     ` Kumar Kartikeya Dwivedi
2021-07-02 11:18 ` [PATCH net-next v6 3/5] bpf: cpumap: implement generic cpumap Kumar Kartikeya Dwivedi
2021-07-02 13:33   ` Jesper Dangaard Brouer [this message]
2021-07-02 11:18 ` [PATCH net-next v6 4/5] bpf: devmap: implement devmap prog execution for generic XDP Kumar Kartikeya Dwivedi
2021-07-02 11:18 ` [PATCH net-next v6 5/5] bpf: tidy xdp attach selftests Kumar Kartikeya Dwivedi
2021-07-08  3:10 ` [PATCH net-next v6 0/5] Generic XDP improvements Alexei Starovoitov

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