On Thu, May 28, 2020 at 10:03:51AM +1000, Dave Chinner wrote: > On Wed, May 27, 2020 at 11:48:58AM -0700, Darrick J. Wong wrote: > > Hi everyone, > > > > Many of you have complained (both publicly and privately) about the > > heavy cost of rebasing your development trees, particularly when you're > > getting close to sending a series out for review. I get it, there have > > been a lot of large refactoring patchsets coming in the past few kernel > > cycles, and this has caused a lot of treewide churn. I don't mind > > cleanups of things that have been weird and wonky about XFS for years, > > but, frankly, rebasing is soul-grinding. > > > > To that end, I propose reducing the frequency of (my own) for-next > > pushes to reduce how often people feel compelled to rebase when they're > > trying to get a series ready for review. > > > > Specifically, I would like to make an informal for-next push schedule as > > follows: > > > > 1 Between -rc1 and -rc4, I'll collect critical bug fixes for the > > merge window that just closed. These should be small changes, so > > I'll put them out incrementally with the goal of landing everything > > in -rc4, and they shouldn't cause major disruptions for anyone else > > working on a big patchset. This is more or less what I've been doing > > up till now -- if it's been on the list for > 24h and someone's > > reviewed it, I'll put it in for-next for wider testing. > > > > 2 A day or two after -rc4 drops. This push is targeted for the next > > merge window. Coming three weeks after -rc1, I hope this will give > > everyone enough time for a round of rebase, review, and debugging of > > large changesets after -rc1. IOWs, the majority of patchsets should > > be ready to go in before we get halfway to the next merge window. > > > > 3 Another push a day or two after -rc6 drops. This will hopefully give > > everyone a second chance to land patchsets that were nearly ready but > > didn't quite make it for -rc4; or other cleanups that would have > > interfered with the first round. Once this is out, we're more or > > less finished with the big patchsets. > > This seems like a reasonable compromise - knowing when updates are > expected goes a long way to being able to plan development and > schedule dev tree updates to avoid repeated rebasing. > > > 4 Perhaps another big push a day or two after -rc8 drops? I'm not keen > > on doing this. It's not often that the kernel goes beyond -rc6 and I > > find it really stressful when the -rc's drag on but people keep > > sending large new patchsets. Talk about stumbling around in the > > dark... > > IMO it's too late at -rc8 to be including big new changes for the > merge window. Bug fixes are fine, but not cleanups or features at > this point because there's too little test and soak time to catch > brown paper bag bugs before it's in the mainline tree and in much > more widespread use. Fair enough. I didn't really like this #4 anyway. Withdrawn. :) > Same goes for merging new stuff during the merge window - last time > around we had updates right up to the merge window, then an update > during the merge window for a second pull request. There just wasn't > any time when the tree wasn't actively moving forward. Urk, sorry about that... I was hoping to land a fix for $largeclient but then the crazy just kept coming. Never gonna do /that/ again. :/ > From my perspective, an update from for-next after the -rc6 update > gets me all the stuff that will be in the next release. That's the > major rebase for my work, and everything pulled in from for-next > starts getting test coverage a couple of weeks out from the merge > window. Once the merge window closes, another local update to the > -rc1 kernel (which should be a no-op for all XFS work) then gets > test coverage for the next release. -rc1 to -rc4 is when > review/rework for whatever I want merged in -rc4/-rc6 would get > posted to the list.... <nod> My workflow is rather different -- I rebase my dev tree off the latest rc every week, and when a series is ready I port it to a branch off of for-next. Occasionally I'll port a refactoring from for-next into my dev tree to keep the code bases similar. Both trees get run through fstests and $whatnot whenever they change, which mean that most mornings I'm looking at nightlies. > This means there's a single rebase event a cycle at -rc6, and the > rest of the time the tree is pretty stable and the base tree I'm > testing is almost always the tree that we need to focus dev testing > on. That is, just before the merge window everyone should be testing > for-next on a -rc6/-rc7 base, and once -rc1 is out, everyone should > be testing that kernel through to ~-rc4 at which point it has > largely stabilised and the cycle starts again.... > > > 5 Obviously, I wouldn't hold back on critical bug fixes to things that > > are broken in for-next, since the goal is to promote testing, not > > hinder it. > > *nod* > > > Hopefully this will cut down on the "arrrgh I was almost ready to send > > this but then for-next jumped and nggghghghg" feelings. :/ > > > > Thoughts? Flames? > > Perhaps: > > - each patch set that is posted should start with "this is aimed at > a 5.x.y-rc4/-rc6 merge" or "still work in progress" so that > everyone has some expectation of when changes are likely to land. <nod> This would probably help with peoples' ability to distinguish djwong patchbombs for submission vs. making backups on NYE. ;) > or: > > - aim to land features and complex bug fixes in -rc4 and cleanups in > -rc6, that way we naturally minimise the rebase work for the > features/bug fixes that are being landed. This may mean that -rc4 > is a small merge if there are no features/bug fixes that meet the > -rc4 merge criteria... I like that idea. --D > Cheers, > > Dave. > -- > Dave Chinner > david@xxxxxxxxxxxxx
