On Fri, Mar 13, 2020 at 05:12:15PM -0400, Josef Bacik wrote: > While debugging Zygo's delayed ref problems it was clear there were a bunch of > cases that we're running delayed refs when we don't need to be, and they result > in a lot of weird latencies. > > Each patch has their individual explanations. But the gist of it is we run > delayed refs in a lot of arbitrary ways that have just accumulated throughout > the years, so clean up all of these so we can have more consistent performance. It would be fine to remove the delayed refs being run from so many places but I vaguely remember some patches adding them with "we have to run delayed refs here or we will miss something and that would be a corruption". The changelogs in patches from 3 on don't point out any specific problems and I miss some reasoning about correctness, ideally for each line of btrfs_run_delayed_refs removed. As a worst case I really don't want to get to a situation where we start getting reports that something broke because of the missing delayed refs, followed by series of "oh yeah I forgot we need it here, add it back". The branch with this patchset is in for-next but I'm still not comfortable with adding it to misc-next as I can't convince myself it's safe, so more reviews are welcome.
