From: Paolo Abeni <pabeni@redhat.com>
To: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Cc: Network Development <netdev@vger.kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Steffen Klassert <steffen.klassert@secunet.com>,
Alexander Lobakin <alobakin@pm.me>
Subject: Re: [PATCH net-next v2 1/8] udp: fixup csum for GSO receive slow path
Date: Mon, 29 Mar 2021 17:00:09 +0200 [thread overview]
Message-ID: <c296fa344bacdcd23049516e8404931abc70b793.camel@redhat.com> (raw)
In-Reply-To: <CA+FuTSduw1eK+CuEgzzwA+6QS=QhMhFQpgyVGH2F8aNH5gwv5A@mail.gmail.com>
On Mon, 2021-03-29 at 09:52 -0400, Willem de Bruijn wrote:
> > > That breaks the checksum-and-copy optimization when delivering to
> > > local sockets. I wonder if that is a regression.
> >
> > The conversion to CHECKSUM_UNNECESSARY happens since
> > commit 573e8fca255a27e3573b51f9b183d62641c47a3d.
> >
> > Even the conversion to CHECKSUM_PARTIAL happens independently from this
> > series, since commit 6f1c0ea133a6e4a193a7b285efe209664caeea43.
> >
> > I don't see a regression here ?!?
>
> I mean that UDP packets with local destination socket and no tunnels
> that arrive with CHECKSUM_NONE normally benefit from the
> checksum-and-copy optimization in recvmsg() when copying to user.
>
> If those packets are now checksummed during GRO, that voids that
> optimization, and the packet payload is now touched twice.
The 'now' part confuses me. Nothing in this patch or this series
changes the processing of CHECKSUM_NONE UDP packets with no tunnel.
I do see checksum validation in the GRO engine for CHECKSUM_NONE UDP
packet prior to this series.
I *think* the checksum-and-copy optimization is lost
since 573e8fca255a27e3573b51f9b183d62641c47a3d.
Regards,
Paolo
next prev parent reply other threads:[~2021-03-29 15:01 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-25 17:23 [PATCH net-next v2 0/8] udp: GRO L4 improvements Paolo Abeni
2021-03-25 17:24 ` [PATCH net-next v2 1/8] udp: fixup csum for GSO receive slow path Paolo Abeni
2021-03-26 18:30 ` Willem de Bruijn
2021-03-29 11:25 ` Paolo Abeni
2021-03-29 12:28 ` Willem de Bruijn
2021-03-29 13:24 ` Paolo Abeni
2021-03-29 13:52 ` Willem de Bruijn
2021-03-29 15:00 ` Paolo Abeni [this message]
2021-03-29 15:24 ` Willem de Bruijn
2021-03-29 16:23 ` Paolo Abeni
2021-03-29 22:37 ` Willem de Bruijn
2021-03-25 17:24 ` [PATCH net-next v2 2/8] udp: skip L4 aggregation for UDP tunnel packets Paolo Abeni
2021-03-26 18:23 ` Willem de Bruijn
2021-03-25 17:24 ` [PATCH net-next v2 3/8] udp: properly complete L4 GRO over UDP tunnel packet Paolo Abeni
2021-03-26 17:51 ` Willem de Bruijn
2021-03-25 17:24 ` [PATCH net-next v2 4/8] udp: never accept GSO_FRAGLIST packets Paolo Abeni
2021-03-26 18:15 ` Willem de Bruijn
2021-03-29 8:11 ` Paolo Abeni
2021-03-29 12:31 ` Willem de Bruijn
2021-03-29 13:29 ` Paolo Abeni
2021-03-25 17:24 ` [PATCH net-next v2 5/8] vxlan: allow L4 GRO passthrough Paolo Abeni
2021-03-25 17:24 ` [PATCH net-next v2 6/8] geneve: allow UDP L4 GRO passthrou Paolo Abeni
2021-03-25 17:24 ` [PATCH net-next v2 7/8] bareudp: " Paolo Abeni
2021-03-25 17:24 ` [PATCH net-next v2 8/8] selftests: net: add UDP GRO forwarding self-tests Paolo Abeni
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