Hi Eduardo, On Wednesday, July 25, 2018 8:18:46 PM CEST Eduardo Valentin wrote: > System instability are seen during resume from hibernation when system > is under heavy CPU load. This is due to the lack of update of sched > clock data, and the scheduler would then think that heavy CPU hog > tasks need more time in CPU, causing the system to freeze > during the unfreezing of tasks. For example, threaded irqs, > and kernel processes servicing network interface may be delayed > for several tens of seconds, causing the system to be unreachable. > > Situation like this can be reported by using lockup detectors > such as workqueue lockup detectors: > > Message from syslogd@ip-172-31-67-114 at May 7 18:23:21 ... > kernel:BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for > 57s! > > Message from syslogd@ip-172-31-67-114 at May 7 18:23:21 ... > kernel:BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for > 57s! > > Message from syslogd@ip-172-31-67-114 at May 7 18:23:21 ... > kernel:BUG: workqueue lockup - pool cpus=3 node=0 flags=0x1 nice=0 stuck for > 57s! > > Message from syslogd@ip-172-31-67-114 at May 7 18:29:06 ... > kernel:BUG: workqueue lockup - pool cpus=3 node=0 flags=0x1 nice=0 stuck for > 403s! > > The fix for this situation is to mark the sched clock as unstable > as early as possible in the resume path, leaving it unstable > for the duration of the resume process. This will force the > scheduler to attempt to align the sched clock across CPUs using > the delta with time of day, updating sched clock data. In a post > hibernation event, we can then mark the sched clock as stable > again, avoiding unnecessary syncs with time of day on systems > in which TSC is reliable. > > Cc: Thomas Gleixner <[email protected]> > Cc: Ingo Molnar <[email protected]> > Cc: "H. Peter Anvin" <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: Dou Liyang <[email protected]> > Cc: Len Brown <[email protected]> > Cc: "Rafael J. Wysocki" <[email protected]> > Cc: Eduardo Valentin <[email protected]> > Cc: "[email protected]" <[email protected]> > Cc: Rajvi Jingar <[email protected]> > Cc: Pavel Tatashin <[email protected]> > Cc: Philippe Ombredanne <[email protected]> > Cc: Kate Stewart <[email protected]> > Cc: Greg Kroah-Hartman <[email protected]> > Cc: [email protected] > Cc: [email protected] > Signed-off-by: Eduardo Valentin <[email protected]>
Can you please resend this with a CC to linux-pm? Cheers, Rafael
