On 24/01/2019 12:21, Arkadiusz Miśkiewicz wrote: > On 17/01/2019 14:17, Arkadiusz Miśkiewicz wrote: >> On 17/01/2019 13:25, Aleksa Sarai wrote: >>> On 2019-01-17, Arkadiusz Miśkiewicz <a.miskiewicz@xxxxxxxxx> wrote: >>>> Using kernel 4.19.13. >>>> >>>> For one cgroup I noticed weird behaviour: >>>> >>>> # cat pids.current >>>> 60 >>>> # cat cgroup.procs >>>> # >>> >>> Are there any zombies in the cgroup? pids.current is linked up directly >>> to __put_task_struct (so exit(2) won't decrease it, only the task_struct >>> actually being freed will decrease it). >>> >> >> There are no zombie processes. >> >> In mean time the problem shows on multiple servers and so far saw it >> only in cgroups that were OOMed. >> >> What has changed on these servers (yesterday) is turning on >> memory.oom.group=1 for all cgroups and changing memory.high from 1G to >> "max" (leaving memory.max=2G limit only). >> >> Previously there was no such problem. >> > > I'm attaching reproducer. This time tried on different distribution > kernel (arch linux). > > After 60s pids.current still shows 37 processes even if there are no > processes running (according to ps aux). The same test on 5.0.0-rc3-00104-gc04e2a780caf and it's easy to reproduce bug. No processes in cgroup but pids.current reports 91. memory.oom.group=0 - everything works fine, pids are counted properly memory.oom.group=1 - bug becomes visible [root@xps test]# python3 cg.py Created cgroup: /sys/fs/cgroup/test_5277 Start: pids.current: 0 Start: cgroup.procs: 0: pids.current: 103 0: cgroup.procs: 1: pids.current: 91 1: cgroup.procs: 2: pids.current: 91 2: cgroup.procs: 3: pids.current: 91 3: cgroup.procs: 4: pids.current: 91 4: cgroup.procs: 5: pids.current: 91 5: cgroup.procs: 6: pids.current: 91 6: cgroup.procs: 7: pids.current: 91 7: cgroup.procs: 8: pids.current: 91 8: cgroup.procs: 9: pids.current: 91 9: cgroup.procs: 10: pids.current: 91 10: cgroup.procs: 11: pids.current: 91 11: cgroup.procs: [root@xps test]# uname -a Linux xps 5.0.0-rc3-00104-gc04e2a780caf #288 SMP PREEMPT Thu Jan 24 19:00:32 CET 2019 x86_64 Intel(R)_Core(TM)_i9-8950HK_CPU_@_2.90GHz PLD Linux cc relevant people script is here: https://www.spinics.net/lists/cgroups/msg21330.html > > [root@warm ~]# uname -a > Linux warm 4.20.3-arch1-1-ARCH #1 SMP PREEMPT Wed Jan 16 22:38:58 UTC > 2019 x86_64 GNU/Linux > [root@warm ~]# python3 cg.py > Created cgroup: /sys/fs/cgroup/test_26207 > Start: pids.current: 0 > Start: cgroup.procs: > 0: pids.current: 62 > 0: cgroup.procs: > 1: pids.current: 37 > 1: cgroup.procs: > 2: pids.current: 37 > 2: cgroup.procs: > 3: pids.current: 37 > 3: cgroup.procs: > 4: pids.current: 37 > 4: cgroup.procs: > 5: pids.current: 37 > 5: cgroup.procs: > 6: pids.current: 37 > 6: cgroup.procs: > 7: pids.current: 37 > 7: cgroup.procs: > 8: pids.current: 37 > 8: cgroup.procs: > 9: pids.current: 37 > 9: cgroup.procs: > 10: pids.current: 37 > 10: cgroup.procs: > 11: pids.current: 37 > 11: cgroup.procs: > -- Arkadiusz Miśkiewicz, arekm / ( maven.pl | pld-linux.org )
