Omar Kilani <omar.kil...@gmail.com> wrote: > Hi there, > > I’m still trying to piece together a reproducible test that triggers > this, but I wanted to post in case someone goes “hmmm... change X > might have done this”.
Maybe Davidlohr knows, since he's responsible for most of the epoll changes in 5.0. > Basically, something’s broken (or at least, has changed enough to > cause problems in user space) in epoll since 5.0. It’s still broken in > 5.1-rc5. > > It doesn’t happen 100% of the time. It’s sort of hard to pin down but > I’ve observed the following: > > * nginx not accepting connections under load > * A java app which uses netty / NIO having strange writability > semantics on channels, which confuses netty / java enough to not > properly flush written data on the socket. > > I went and tested these Linux kernels: > > 4.20.17 > 4.19.32 > 4.14.111 > > And the issue(s) do not show up there. > > I’m still actively chasing this up, and will report back — I haven’t > touched kernel code in 15 years so I’m a little rusty. :) > > Regards, > Omar
