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From: Alexei Starovoitov <ast@plumgrid.com>
To: Daniel Borkmann <daniel@iogearbox.net>, davem@davemloft.net
Cc: jhs@mojatatu.com, edumazet@google.com, netdev@vger.kernel.org
Subject: Re: [PATCH net-next] net: use jump label patching for ingress qdisc in __netif_receive_skb_core
Date: Sat, 11 Apr 2015 08:40:57 -0700	[thread overview]
Message-ID: <55294089.6030202@plumgrid.com> (raw)
In-Reply-To: <66b2c2faaa0f629dd9a8c0981bf51f6484bc4ee9.1428699635.git.daniel@iogearbox.net>

On 4/10/15 2:07 PM, Daniel Borkmann wrote:
> Even if we make use of classifier and actions from the egress
> path, we're going into handle_ing() executing additional code
> on a per-packet cost for ingress qdisc, just to realize that
> nothing is attached on ingress.
>
> Instead, this can just be blinded out as a no-op entirely with
> the use of a static key. On input fast-path, we already make
> use of static keys in various places, e.g. skb time stamping,
> in RPS, etc. It makes sense to not waste time when we're assured
> that no ingress qdisc is attached anywhere.
>
> Enabling/disabling of that code path is being done via two
> helpers, namely net_{inc,dec}_ingress_queue(), that are being
> invoked under RTNL mutex when a ingress qdisc is being either
> initialized or destructed.
>
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tested this patch standalone and with ingress_l2 on top.
Acked-by: Alexei Starovoitov <ast@plumgrid.com>

  parent reply	other threads:[~2015-04-11 15:40 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-10 21:07 [PATCH net-next] net: use jump label patching for ingress qdisc in __netif_receive_skb_core Daniel Borkmann
2015-04-10 22:30 ` Eric Dumazet
2015-04-10 22:34   ` Daniel Borkmann
2015-04-10 22:40   ` Alexei Starovoitov
2015-04-11  1:14 ` Cong Wang
2015-04-11  1:41   ` Alexei Starovoitov
2015-04-11 15:40 ` Alexei Starovoitov [this message]
2015-04-13 17:35 ` David Miller

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