Re: bpf-next experiment

Andrii Nakryiko
2024-08-15T21:54:10Z

On Thu, Aug 15, 2024 at 8:54 AM Simon Horman <horms@kernel.org> wrote:
>
> On Wed, Aug 14, 2024 at 12:32:00PM -0700, Alexei Starovoitov wrote:
> > Hi All,
> >
> > Couple years ago folks suggested that bpf-next should be
> > a separate pull request to increase subsystem visibility.
> > Back then we rejected the idea since many networking related
> > changes required bpf core changes. Things are different now.
> > bpf kfuncs can be added independently by various subsystems,
> > verifier additions are mainly driven by sched-ext,
> > so it's time to give it a shot. It's an experiment.
> > If things don't work out as expected we will go back to
> > the old model of feeding bpf trees through net/net-next trees.
> >
> > So here is the plan:
> >
> > 1. bpf fixes go directly to Linus (skipping net tree) and
> > net/bpf trees are fast forwarded afterwards as usual.
> >
> > 2. Non-networking bpf commits land in bpf-next/master branch.
> > It will form bpf-next PR during the merge window.
> >
> > 3. Networking related commits (like XDP) land in bpf-next/net branch.
> > They will be PR-ed to net-next and ffwded from net-next
> > as we do today. All these patches will get to mainline
> > via net-next PR.
>
> Hi Alexei,
>
> Nice plan :)
>
> I wonder if, bpf-next/net-next might be a more intuitive name, as the
> proposed branch is closely related to net-next.
>
> OTOH, mabey one '-next', as per your proposal, is enough :)
>
> >
> > 4. bpf-next/master and bpf-next/net branches are manually
> > merged into bpf-next/for-next branch.
> > This step achieves two objectives:
> > - bpf maintainers watch for conflicts between /master and /net
> > - Stephen Rothwell continues taking /for-next branch into linux-next
> > as usual
> >
> > bpf CI will run tests against 4 trees (instead of 2):
> > bpf, bpf-next/master, bpf-next/net, bpf-next/for-next.

BPF CI has been set up to recognize "bpf-net" as a marker for
bpf-next/net branch. We can update that, of course, but just FYI what
is currently recognized.

> > This is wip. Watch for more "Checks" in patchwork.
> >
> > By the merge window in September we will reassess
> > the situation and if it's still worth doing we will
> > proceed with PR formed from bpf-next/master.
> > If not, we will PR bpf-next/master into net-next and
> > call it a failed experiment.
> >
> > We feel that there are more positives to this process
> > than headaches, so fingers crossed.
> >