Date: Wed, 17 Apr 2024 02:35:21 +0000 From: Colin Percival <cperciva@tarsnap.com> To: Lexi Winter <lexi@le-fay.org>, arch@freebsd.org Subject: Re: enable INVARIANT_SUPPORT in GENERIC in release builds Message-ID: <0100018ee9e8a381-2e0a8845-5321-4841-bfaf-184376e88112-000000@email.amazonses.com> In-Reply-To: <Zh7m7yKbNKafuU0J@ilythia.eden.le-fay.org> References: <Zh7m7yKbNKafuU0J@ilythia.eden.le-fay.org>
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On 4/16/24 14:00, Lexi Winter wrote: > currently release version of GENERIC (or GENERIC-NODEBUG in main) does > not have INVARIANT_SUPPORT enabled. > > unfortunately, the presence or absense of this option breaks the KABI > because, as i understand it, modules built with INVARIANTS won't load on > a kernel without INVARIANT_SUPPORT. > > is there a reason INVARIANT_SUPPORT can't just be enabled by default? I think while it had much lower overhead than INVARIANTS, there was still a significant overhead cost at least in the early days. Maybe that's no longer the case. > this would remove one roadblock to separating kernel modules from the > kernel config in both pkgbase and ports, because there would be no need > to build a KABI-incompatible kernel just to build a single module with > INVARIANTS. If the overhead cost of INVARIANT_SUPPORT is no longer relevant, I'd be fine with including it in stable/15. Of course we can't turn it on for stable/1[34] for the ABI reasons you just mentioned. -- Colin Percival FreeBSD Release Engineering Lead & EC2 platform maintainer Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid
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