On Mon, Dec 19, 2011 at 02:11:08PM -0200, Marcelo Tosatti wrote: > On Mon, Dec 19, 2011 at 02:59:10PM +0200, Avi Kivity wrote: > > On 12/16/2011 11:31 AM, Marcelo Tosatti wrote: > > > > > > > > > > Slow enough that progress of the watchdog thread is unable to keep up > > > > > with timer interrupt processing. This is considered a hang and > > > > > should be reported. > > > > > > > > It's not a guest hang though! > > > > > > No, but your host system is in such a load state that for the sake of > > > system usability you better print out a warning message. > > > > What's the point in printing it in the guest? The guest can't observe > > host conditions. > > > > > I don't see the advantage of preempt notifiers over the simple, paravirt > > > solution proposed? Note kvmclock is already paravirt. > > > > Right. > > > > > What do you want to be done in preempt notifiers? Measure what to > > > consider setting this flag? > > > > Preemption while TASK_RUNNING or TASK_UNINTERRUPTIBLE. > > Maybe it is good (not sure), need to look into schedstats and think of > cases that would break legitimate guest hangs. And it probably also > affects the position of clearing the flag on the guest side as its > currently done in Eric's patchset. Is the task going to be TASK_UNINTERRUPTIBLE with SIGSTOP? Don't think so. Note "Preemption while TASK_RUNNING or TASK_UNINTERRUPTIBLE" is not functional for guest-paused-via-QEMU-monitor case. -- 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
