• Anoob Soman's avatar
    xen-evtchn: Bind dyn evtchn:qemu-dm interrupt to next online VCPU · c48f64ab
    Anoob Soman authored
    A HVM domian booting generates around 200K (evtchn:qemu-dm xen-dyn)
    interrupts,in a short period of time. All these evtchn:qemu-dm are bound
    to VCPU 0, until irqbalance sees these IRQ and moves it to a different VCPU.
    In one configuration, irqbalance runs every 10 seconds, which means
    irqbalance doesn't get to see these burst of interrupts and doesn't
    re-balance interrupts most of the time, making all evtchn:qemu-dm to be
    processed by VCPU0. This cause VCPU0 to spend most of time processing
    hardirq and very little time on softirq. Moreover, if dom0 kernel PREEMPTION
    is disabled, VCPU0 never runs watchdog (process context), triggering a
    softlockup detection code to panic.
    Binding evtchn:qemu-dm to next online VCPU, will spread hardirq
    processing evenly across different CPU. Later, irqbalance will try to balance
    evtchn:qemu-dm, if required.
    Signed-off-by: default avatarAnoob Soman <anoob.soman@citrix.com>
    Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
    Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
evtchn.c 16.7 KB