On Thu, Dec 17, 2020 at 5:38 PM Josef <josef.grieb@xxxxxxxxx> wrote: > > > > That is curious. This ticket mentions Shmem though, and in our case it does > > not look suspicious at all. E.g. on a box that has the problem at the moment: > > Shmem: 41856 kB. The box has 256GB of RAM. > > > > But I'd (given my lack of knowledge) expect the issues to be related anyway. > > what about mapped? mapped is pretty high 1GB on my machine, I'm still > reproduce that in C...however the user process is killed but not the > io_wq_worker kernel processes, that's also the reason why the server > socket still listening(even if the user process is killed), the bug > only occurs(in netty) with a high number of operations and using > eventfd_write to unblock io_uring_enter(IORING_ENTER_GETEVENTS) > > (tested on kernel 5.9 and 5.10) Stats from another box with this problem (still 256G of RAM): Mlocked: 17096 kB Mapped: 171480 kB Shmem: 41880 kB Does not look suspicious at a glance. Number of io_wq* processes is 23-31. Uptime is 27 days, 24 rings per process, process was restarted 4 times, 3 out of these four the old instance was killed with SIGKILL. On the last process start 18 rings failed to initialize, but after that 6 more were initialized successfully. It was before the old instance was killed. Maybe it's related to the load and number of io-wq processes, e.g. some of them exited and a few more rings were initialized successfully. -- Dmitry Kadashev
