netdev - Re: [PATCH bpf-next v3 0/5] net: xdp: refactor XDP program queries

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Message-ID: <20190610152433.6e265d6c@cakuba.netronome.com>
Date:   Mon, 10 Jun 2019 15:24:33 -0700
From:   Jakub Kicinski <jakub.kicinski@...ronome.com>
To:     Björn Töpel <bjorn.topel@...il.com>
Cc:     ast@...nel.org, daniel@...earbox.net, netdev@...r.kernel.org,
        magnus.karlsson@...el.com, bjorn.topel@...el.com, toke@...hat.com,
        brouer@...hat.com, bpf@...r.kernel.org, saeedm@...lanox.com
Subject: Re: [PATCH bpf-next v3 0/5] net: xdp: refactor XDP program queries

On Mon, 10 Jun 2019 18:02:29 +0200, Björn Töpel wrote:
> Jakub, what's your thoughts on the special handling of XDP offloading?
> Maybe it's just overkill? Just allocate space for the offloaded
> program regardless support or not? Also, please review the
> dev_xdp_support_offload() addition into the nfp code.

I'm not a huge fan of the new approach - it adds a conditional move,
dereference and a cache line reference to the fast path :(

I think it'd be fine to allocate entries for all 3 types, but the
potential of slowing down DRV may not be a good thing in a refactoring
series.