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[159.2.239.150]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-91c03da5b4asm26796476d6.0.2026.10.20.05.55.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 20 Oct 2026 05:55:21 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1xJ9NA-0000000CTFP-3VJ7; Tue, 20 Oct 2026 09:55:20 -0300 Date: Tue, 20 Oct 2026 09:55:20 -0300 From: Jason Gunthorpe To: Jiri Pirko Cc: linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, x86@kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, david.quigley@intel.com, lukas@wunner.de, ksinyuk@kernel.org, rodrigo.vivi@intel.com, cedric.xing@intel.com, sameo@meta.com, drdeeglaze@gmail.com, James.Bottomley@hansenpartnership.com, aik@amd.com, jpiotrowski@nvidia.com, qinkun@google.com, pgonda@google.com, jic23@kernel.org, alistair.francis@wdc.com, ankita@nvidia.com, suzuki.poulose@arm.com, kas@kernel.org, rick.p.edgecombe@intel.com, elena.reshetova@intel.com, dave.hansen@linux.intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, peter.fang@intel.com Subject: Re: [PATCH RFC 03/20] ctlv: Add the root family specification and generated files Message-ID: <20261020125520.GN14213@ziepe.ca> References: <20261015145053.3664509-1-jiri@resnulli.us> <20261015145053.3664509-4-jiri@resnulli.us> <179245258505.58760.6060356114682279013.b4-review@b4> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Oct 20, 2026 at 02:28:55PM +0200, Jiri Pirko wrote: > Tue, Oct 20, 2026 at 01:29:45AM +0200, jgg@nvidia.com wrote: > >> [ ... 238 lines skipped ... ] > >> --- /dev/null > >> +++ b/Documentation/ctlv/families.yaml > >> @@ -0,0 +1,13 @@ > >> +# SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) > >> +%YAML 1.2 > >> +--- > >> +# Append-only registry of CTLV family names, indexed by family ID: the entry at > >> +# index N has family ID N, up to 65535. The root family owns ID 0 and heads the > >> +# list, and every other entry comes after the entry of the family it inherits. > >> +# An entry may be marked deprecated, but never reordered, removed, renamed or > >> +# reused, its position being its wire identity. Every entry must have a > >> +# specification in specs/.yaml, and is added by the change that adds the > >> +# implementation. Fixtures under tools/ctlv/tests/ are not registered. > >> + > >> +families: > >> + - ctlv > > > >I see where you are coming from with this, but it is going to be > >problematic from a global kernel perspective. Given CTLV is imagined > >as a general tool for any subsystem we cannot control the tree that > >things merge through. It will not be like netdev where there is one > >authoritative tree with a linear history. > > > >So if Bob and Jane maintainers both add their own subsystems by the > >time it gets to Linus the IDs will get scrambled, and bisection will > >be lost. > > > >Either changes to this file must be strictly done in a single tree > >with shared branches (which is going to be a bit hard process wise) > > > >Or we need to put the ID #s here and have some simple process to > >coordinate them during the development process. Since new families are > >probably rare it shouldn't be a big deal > > Exactly. Collision is not very likely. Explicit ID or implicit, scramble > would still happen. And in that case it is resolvable. I think because of process if it is kept like this we will have to merge 'dead code' to reserve spots for people doing new work.. But at a minimum this comment above needs a big fat warning not to change this file without consulting with XYZ to coordinate merging. Jason