Date: Tue, 02 May 2023 09:57:21 +0200 From: Corvin =?ISO-8859-1?Q?K=F6hne?= <corvink@FreeBSD.org> To: Matthew Grooms <mgrooms@shrew.net>, Rob Wing <rob.fx907@gmail.com> Cc: freebsd-hackers@freebsd.org, freebsd-virtualization@freebsd.org, elenamihailescu22@gmail.com, Mihai Carabas <mihai.carabas@gmail.com>, gusev.vitaliy@gmail.com Subject: Re: BHYVE_SNAPSHOT Message-ID: <3ab4e6d94fb0153fb6ff4a53ac6f53b2eaae0cf7.camel@FreeBSD.org> In-Reply-To: <89c84bd7-a925-02f4-acbe-12c3000e7007@shrew.net> References: <ZEz8tU_83QfqbbMu@int21h> <fe221c6a-acb7-ddbd-413d-7039de33e872@shrew.net> <CAF3%2Bn_fN4J4jXH89t8gMOD8QpqAike0Uzrb9wUfKoYv56zQt_w@mail.gmail.com> <89c84bd7-a925-02f4-acbe-12c3000e7007@shrew.net>
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--=-1ejwBLksvRG43eWs0Fu8 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2023-05-02 at 01:16 -0500, Matthew Grooms wrote: > On 4/30/23 21:31, Rob Wing wrote: > > =C2=A0Hey Matthew, > >=20 > > On Sun, Apr 30, 2023 at 1:41=E2=80=AFPM Matthew Grooms <mgrooms@shrew.n= et> > > wrote: > > >=20 > > > =C2=A0Would you like to see support for VM snapshots in the generic > > > kernel? > >=20 > > Is there a review open that addresses the limitations described in > > the commit message that brought the snapshot feature in? > > https://github.com/freebsd/freebsd-src/commit/483d953a86a2507355f8287c5= 107dc827a0ff516 >=20 > Yes. The next set of project goals where not pulled out of thin air. > They were selected specifically to address the limitations that > prevented snapshots from being in the mainline kernel after the > initial commit. That's why patches for AMD CPU, Multiple Devices ( >1 > of the same type ), Capsicum and JSON file format for snapshots were > developed. They were identified as the major per-requisite for > lifting conditional compilation. > > >=20 > > > =C2=A0How about support for warm or live migration? > >=20 > > This builds off the snapshot work, right? Seems like it'd make more > > sense to address the current limitations of the snapshot code > > before extending the functionality off the top of it. >=20 > Yup. See above. I appreciate your input, but the goal of live > migration was set in 2016 with a prototype first demonstrated in > 2018. How long do you suggest a developer wait without review > feedback before moving forward out of tree? The snapshot feature isn't compiled in by default. So, it's likely that changes break it and only a few people are testing it. We have to focus on getting this into the tree. > > > There are experimental patches for all these features that were > > > developed by students at UPB. In a lot of cases, there are open > > > reviews that have been waiting on feedback for ages. > >=20 > > In general, most people don't want to review large experimental > > patches. >=20 > Yup. That approach was attempted with the Warm Migration patches. > From slide 17 in Elena's presentation: >=20 > =C2=A0First review opened in 2021: https://reviews.freebsd.org/D28270 > =C2=A05 reviews from 2022 starting with https://reviews.freebsd.org/D3471= 7 > (same feature split in multiple parts) > =C2=A0 > =C2=A0A similar request was made recently to Gusev Vitaliy WRT the > multiple device support patch which he took ownership of. Thanks for > adding feedback to that review BTW. We'll see how that pans out ... >=20 > =C2=A0https://reviews.freebsd.org/D35590 >=20 I've already reviewed Vitaliy's multi device support patch=C2=A0and people had more than enough time to complain about it. I'm going to commit it as soon as he splits his commit. =C2=A0=C2=A0 > > > =C2=A0The case is quite plain. I'm not sure what the solution is to > > > this=20 > > > =C2=A0problem. I'd love to hear feedback from the community about how > > > I've got=20 > > > =C2=A0this completely wrong and how the course could be corrected. > > > That would=20 > > > =C2=A0be something. > > >=20 > >=20 > > My perspective is that it would have been better to focus student > > efforts on completing the snapshot feature. By completing the > > snapshot feature, I mean getting the code into a state where it's > > compiled in by default and no longer considered an experimental > > feature. > >=20 > I'm not sure what more to say hear regarding the snapshot feature or > what might have been done in the past. We need a solution for the > present. If you have any comments related to the follow up reviews > submitted by UPB, I'm sure they'd love to hear them. > And lastly: I get that FreeBSD is a non paid volunteer project for > most. Without the efforts of folks like Peter, Neel, John and others, > there would be no bhyve. I'm not saying that they, as project > maintainers, should somehow be doing more. We all have limited time > to invest, paid work to do and families to feed. I'm asking if there > are other developers that might be willing and able to help with > reviews? Is there something the FreeBSD foundation can do help out in > situations like these? > Thanks, > -Matthew > =C2=A0 UPB has developed some interesting features and I'd like to see those in tree. I can take some time to review the patches. Nevertheless, we really need the snapshot feature compiled in by default. Otherwise, it's wasted time for all of us. --=20 Kind regards, Corvin --=-1ejwBLksvRG43eWs0Fu8 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEgvRSla3m2t/H2U9G2FTaVjFeAmoFAmRQwmEACgkQ2FTaVjFe Amq4vxAAumSDeuzxwoIng8rnHPIuaUYlTyQveawd+FEGs32aulOJvBs3hgs0KLNm t8C7uj04JjENwj4USNOVYFh87pfk9L5Qve0pmDbkJHRqI/3nNWj8WGhs3Bk4yWtH /b5yXSsrM8PBXBowKX+nYGOj7LJxayLUof/glSNJgNbCTy0/7v9qtCDLc2BMTfXU BZNVo405iJdaTvktDFTrugApWvpUb8hSETaDknZa8pV6UXmerAcR3VVb9Xfe75fS UWuamynh0s5IEJGA5d6Da30aI16Bv9cTvqNJuC05MlWJ/7Oy/G3YMMjuNW4zK+9U 9ePpgu49ZEl2AZlmGpI8O8zoZMw58Cr3YRVgj1cyEBi0Zv97nbvhCZW9ujvmQ3lQ Ub7GcIxQ6EHYKYik9DXruedH0HPwZB5OPHPRCPYM4YPL/47ayyjUcHkleSCMnc2n nA3Zga+0yr3H0qNHcGs3TzWMhUj4x7wrYf4bOi0y6SlHsFkCvWd1jJybRqbGpPR4 9rY9Dpjp8CrVfVloAe8tLp+Npwxs7ddU/EAplgv1NdaE6yzEXDBYoZ6xAjMynNkr G63mZ/+iq0bxwWtdR2gznJYy6PPCkb5o13tGnIoW6236sMA2iHHQkMrskzq8k75M yGq+0lsSWNt13+9pXsX75dhpMZGs5D4SA/lnTNAAdsFliFdVHMw= =dU7I -----END PGP SIGNATURE----- --=-1ejwBLksvRG43eWs0Fu8--
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