From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: Jon Kohler <jon@nutanix.com>,
ast@kernel.org, daniel@iogearbox.net, davem@davemloft.net,
kuba@kernel.org, hawk@kernel.org, john.fastabend@gmail.com,
netdev@vger.kernel.org, bpf@vger.kernel.org, jon@nutanix.com,
aleksander.lobakin@intel.com,
Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
Jason Wang <jasowang@redhat.com>,
Andrew Lunn <andrew+netdev@lunn.ch>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>,
linux-kernel@vger.kernel.org (open list)
Subject: Re: [PATCH net-next 1/4] tun: rcu_deference xdp_prog only once per batch
Date: Wed, 07 May 2025 16:43:32 -0400 [thread overview]
Message-ID: <681bc5f4b261e_20dc6429482@willemb.c.googlers.com.notmuch> (raw)
In-Reply-To: <20250506145530.2877229-2-jon@nutanix.com>
Jon Kohler wrote:
> Hoist rcu_dereference(tun->xdp_prog) out of tun_xdp_one, so that
> rcu_deference is called once during batch processing.
I'm skeptical that this does anything.
The compiler can inline tun_xdp_one and indeed seems to do so. And
then it can cache the read in a register if that is the best use of
a register.
>
> No functional change intended.
>
> Signed-off-by: Jon Kohler <jon@nutanix.com>
next prev parent reply other threads:[~2025-05-07 20:43 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20250506145530.2877229-1-jon@nutanix.com>
2025-05-06 14:55 ` Jon Kohler
2025-05-07 20:43 ` Willem de Bruijn [this message]
2025-05-08 3:13 ` Jon Kohler
2025-05-08 13:31 ` Willem de Bruijn
2025-05-08 13:40 ` Jon Kohler
2025-05-06 14:55 ` [PATCH net-next 2/4] tun: optimize skb allocation in tun_xdp_one Jon Kohler
2025-05-07 20:50 ` Willem de Bruijn
2025-05-08 3:02 ` Jon Kohler
2025-05-06 14:55 ` [PATCH net-next 3/4] tun: use napi_build_skb in __tun_build_skb Jon Kohler
2025-05-07 20:50 ` Willem de Bruijn
2025-05-08 3:08 ` Jon Kohler
2025-05-06 14:55 ` [PATCH net-next 4/4] tun: use napi_consume_skb in tun_do_read Jon Kohler
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