On 12/08/2011 05:19 PM, Eric B Munson wrote: > > error compiling committee.c: too many arguments to function > > > My concern for preempt notifiers is masking real soft lockup warnings. If the > flag is set every time the vm is preempted, it becomes more likely that we will > mask real warnings. The ioctl was choosen because it sets the flag only when > the guest is being paused deliberately. > > AFAIK, SIGSTOP is not a supported way to stop a qemu vm so a soft lockup This is a kvm patch, not a qemu patch. In general we try to address general requirements, not just those that are specific to one userspace, even if it is near to our hearts. > warning would be working as designed there. If that isn't the case, or if it > ever changes, we could always install a signal handler for SIGCONT that set the > flag before resuming the vm. > > Scheduling delays are also beyond the scope of this problem and I see the soft > lockup warning as appropriate in that case. I don't think you should see a guest softlockup if the host is overloaded. Nor should you see it due to a long live migration pause, or STOP/CONT. You should see a guest softlockup if it is spinning due to a guest bug, and not for any other reason. I think we need a mix of the ioctl (for STOP/CONT and voluntary pauses, like live migration or qemu stop/cont) and preempt notifiers (together with a check for TASK_RUNNING/TASK_UNINTERRUPTIBLE, for scheduling or swap delays) -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
