Re: [PATCH net-next] idpf: do not linearize big TSO packets

[Brian Vazquez <brianvv@google.com>]

Tested-by: Brian Vazquez <brianvv@google.com>


On Wed, Aug 20, 2025 at 12:27 AM Hay, Joshua A <joshua.a.hay@intel.com> wrote:
>
> > From: Eric Dumazet <edumazet@google.com>
> >
> > idpf has a limit on number of scatter-gather frags
> > that can be used per segment.
> >
> > Currently, idpf_tx_start() checks if the limit is hit
> > and forces a linearization of the whole packet.
> >
> > This requires high order allocations that can fail
> > under memory pressure. A full size BIG-TCP packet
> > would require order-7 alocation on x86_64 :/
> >
> > We can move the check earlier from idpf_features_check()
> > for TSO packets, to force GSO in this case, removing the
> > cost of a big copy.
> >
> > This means that a linearization will eventually happen
> > with sizes smaller than one MSS.
> >
> > __idpf_chk_linearize() is renamed to idpf_chk_tso_segment()
> > and moved to idpf_lib.c
> >
> > Signed-off-by: Eric Dumazet <edumazet@google.com>
> > Cc: Tony Nguyen <anthony.l.nguyen@intel.com>
> > Cc: Przemek Kitszel <przemyslaw.kitszel@intel.com>
> > Cc: Jacob Keller <jacob.e.keller@intel.com>
> > Cc: Madhu Chittim <madhu.chittim@intel.com>
> > Cc: Pavan Kumar Linga <pavan.kumar.linga@intel.com>
> > Cc: Joshua Hay <joshua.a.hay@intel.com>
> > Cc: Brian Vazquez <brianvv@google.com>
> > Cc: Willem de Bruijn <willemb@google.com>
> > Cc: Andrew Lunn <andrew+netdev@lunn.ch>
> > ---
> Reviewed-by: Joshua Hay <joshua.a.hay@intel.com>