RHEL6 and RHEL7 kernels are broken with respect to SCHED_RESET_ON_FORK feature. If this flag is defined, CTDB relies on fork() to reset the priority of the child processes. In RHEL6 the scheduling class is reset, but the process priority is not. In RHEL7 the scheduling class is not reset, so all child processes will continue to run with real-time priority.
Created attachment 12601 [details] Patches for v4-5
Created attachment 12602 [details] Patches for v4-4
Hi Karolin, This is ready for 4.5/4.4. If there's still a chance of squeezing it into the releases you're doing today then that would be tremendous. If not then that's the way things go... :-) Thanks...
(In reply to Martin Schwenke from comment #3) Sorry, those last minute stunts usually break the whole release... ;-) Pushed to autobuild-v4-{5,4}-test.
(In reply to Karolin Seeger from comment #4) Pushed to both branches. Closing out bug report. Thanks!
The fix is incomplete. Earlier we were relying on SCHED_RESET_ON_FORK to reset the priority of lock helper processes. Since SCHED_RESET_ON_FORK support has been removed, the scheduling priority of child processes created using vfork() need to be reset explicitly in the helper processes.
(In reply to Amitay Isaacs from comment #6) So this also needs to be pushed to 4.5 (and probably 4.4 as well) right ...?
(In reply to Steve French from comment #7) Yes. Both 4.5 and 4.4.
Created attachment 12678 [details] Additional patch for v4-4
Created attachment 12679 [details] Additional patch for v4-5
Hi Karolin, Additional patches are ready for 4.4/4.5. Thanks!
(In reply to Martin Schwenke from comment #11) Pushed to autobuild-v4-{5,4}-test.
(In reply to Karolin Seeger from comment #12) Pushed to both branches. Closing out bug report. Thanks!