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From: "Björn Töpel" <bjorn.topel@intel.com>
To: "Jakub Kicinski" <jakub.kicinski@netronome.com>,
	"Björn Töpel" <bjorn.topel@gmail.com>
Cc: ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org,
	magnus.karlsson@intel.com, toke@redhat.com, brouer@redhat.com,
	bpf@vger.kernel.org, saeedm@mellanox.com
Subject: Re: [PATCH bpf-next v3 0/5] net: xdp: refactor XDP program queries
Date: Tue, 11 Jun 2019 09:24:41 +0200	[thread overview]
Message-ID: <980c54f7-e270-f6cf-089d-969cebad8f38@intel.com> (raw)
In-Reply-To: <20190610152433.6e265d6c@cakuba.netronome.com>

On 2019-06-11 00:24, Jakub Kicinski wrote:
> 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.
> 

Note, that currently it's "only" the XDP_SKB path that's affected, but
yeah, I agree with out. And going forward, I'd like to use the netdev
xdp_prog from the Intel drivers, instead of spreading/caching it all over.

I'll go back to the drawing board. Any suggestions on a how/where the
program should be stored in the netdev are welcome! :-) ...or maybe just
simply store the netdev_xdp flat (w/o the additional allocation step) in
net_device. Three programs and the boolean (remove the num_progs).


Björn

  reply	other threads:[~2019-06-11  7:24 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-10 16:02 [PATCH bpf-next v3 0/5] net: xdp: refactor XDP program queries Björn Töpel
2019-06-10 16:02 ` [PATCH bpf-next v3 1/5] net: xdp: refactor XDP_QUERY_PROG{,_HW} to netdev Björn Töpel
2019-06-10 16:02 ` [PATCH bpf-next v3 2/5] nfp, netdevsim: use dev_xdp_support_offload() function Björn Töpel
2019-06-10 16:02 ` [PATCH bpf-next v3 3/5] net: xdp: remove XDP_QUERY_PROG{,_HW} Björn Töpel
2019-06-10 16:02 ` [PATCH bpf-next v3 4/5] net: xdp: refactor XDP flags checking Björn Töpel
2019-06-10 16:02 ` [PATCH bpf-next v3 5/5] net: xdp: remove xdp_attachment_flags_ok() and flags member Björn Töpel
2019-06-10 22:24 ` [PATCH bpf-next v3 0/5] net: xdp: refactor XDP program queries Jakub Kicinski
2019-06-11  7:24   ` Björn Töpel [this message]
2019-06-11 12:17     ` Toke Høiland-Jørgensen
2019-06-11 17:22     ` Jakub Kicinski
2019-06-12  5:38       ` Björn Töpel
2019-06-12 14:31     ` Jonathan Lemon

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