From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Hangbin Liu <liuhangbin@gmail.com>
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org,
"Toke Høiland-Jørgensen" <toke@redhat.com>,
"Jiri Benc" <jbenc@redhat.com>,
"Eelco Chaudron" <echaudro@redhat.com>,
ast@kernel.org, "Daniel Borkmann" <daniel@iogearbox.net>,
"Lorenzo Bianconi" <lorenzo.bianconi@redhat.com>,
"David Ahern" <dsahern@gmail.com>,
"Andrii Nakryiko" <andrii.nakryiko@gmail.com>,
"Alexei Starovoitov" <alexei.starovoitov@gmail.com>,
"John Fastabend" <john.fastabend@gmail.com>,
"Maciej Fijalkowski" <maciej.fijalkowski@intel.com>,
"Björn Töpel" <bjorn.topel@gmail.com>,
"Martin KaFai Lau" <kafai@fb.com>,
brouer@redhat.com
Subject: Re: [PATCHv9 bpf-next 2/4] xdp: extend xdp_redirect_map with broadcast support
Date: Thu, 22 Apr 2021 18:53:32 +0200 [thread overview]
Message-ID: <20210422185332.3199ca2e@carbon> (raw)
In-Reply-To: <20210422071454.2023282-3-liuhangbin@gmail.com>
On Thu, 22 Apr 2021 15:14:52 +0800
Hangbin Liu <liuhangbin@gmail.com> wrote:
> diff --git a/net/core/filter.c b/net/core/filter.c
> index cae56d08a670..afec192c3b21 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
[...]
> int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
> struct bpf_prog *xdp_prog)
> {
> @@ -3933,6 +3950,7 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
> enum bpf_map_type map_type = ri->map_type;
> void *fwd = ri->tgt_value;
> u32 map_id = ri->map_id;
> + struct bpf_map *map;
> int err;
>
> ri->map_id = 0; /* Valid map id idr range: [1,INT_MAX[ */
> @@ -3942,7 +3960,12 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
> case BPF_MAP_TYPE_DEVMAP:
> fallthrough;
> case BPF_MAP_TYPE_DEVMAP_HASH:
> - err = dev_map_enqueue(fwd, xdp, dev);
> + map = xchg(&ri->map, NULL);
Hmm, this looks dangerous for performance to have on this fast-path.
The xchg call can be expensive, AFAIK this is an atomic operation.
> + if (map)
> + err = dev_map_enqueue_multi(xdp, dev, map,
> + ri->flags & BPF_F_EXCLUDE_INGRESS);
> + else
> + err = dev_map_enqueue(fwd, xdp, dev);
> break;
> case BPF_MAP_TYPE_CPUMAP:
> err = cpu_map_enqueue(fwd, xdp, dev);
> @@ -3984,13 +4007,19 @@ static int xdp_do_generic_redirect_map(struct net_device *dev,
> enum bpf_map_type map_type, u32 map_id)
> {
> struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);
> + struct bpf_map *map;
> int err;
>
> switch (map_type) {
> case BPF_MAP_TYPE_DEVMAP:
> fallthrough;
> case BPF_MAP_TYPE_DEVMAP_HASH:
> - err = dev_map_generic_redirect(fwd, skb, xdp_prog);
> + map = xchg(&ri->map, NULL);
Same here!
> + if (map)
> + err = dev_map_redirect_multi(dev, skb, xdp_prog, map,
> + ri->flags & BPF_F_EXCLUDE_INGRESS);
> + else
> + err = dev_map_generic_redirect(fwd, skb, xdp_prog);
> if (unlikely(err))
> goto err;
> break;
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
next prev parent reply other threads:[~2021-04-22 16:54 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-22 7:14 [PATCHv9 bpf-next 0/4] xdp: extend xdp_redirect_map with broadcast support Hangbin Liu
2021-04-22 7:14 ` [PATCHv9 bpf-next 1/4] bpf: run devmap xdp_prog on flush instead of bulk enqueue Hangbin Liu
2021-04-22 7:14 ` [PATCHv9 bpf-next 2/4] xdp: extend xdp_redirect_map with broadcast support Hangbin Liu
2021-04-22 16:53 ` Jesper Dangaard Brouer [this message]
2021-04-22 18:02 ` Toke Høiland-Jørgensen
2021-04-23 16:54 ` Jesper Dangaard Brouer
2021-04-24 1:09 ` Hangbin Liu
2021-04-24 7:01 ` Jesper Dangaard Brouer
2021-04-24 9:53 ` Toke Høiland-Jørgensen
2021-04-24 13:55 ` Hangbin Liu
2021-04-26 6:01 ` Hangbin Liu
2021-04-26 9:23 ` Jesper Dangaard Brouer
2021-04-26 10:25 ` Hangbin Liu
2021-04-22 7:14 ` [PATCHv9 bpf-next 3/4] sample/bpf: add xdp_redirect_map_multi for redirect_map broadcast test Hangbin Liu
2021-04-22 7:14 ` [PATCHv9 bpf-next 4/4] selftests/bpf: add xdp_redirect_multi test Hangbin Liu
2021-04-26 9:28 ` Jesper Dangaard Brouer
2021-04-26 10:19 ` Hangbin Liu
2021-04-26 14:29 ` Toke Høiland-Jørgensen
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