From: Wanpeng Li <[email protected]> Retry tune per-vCPU timer_advance_ns if adaptive tuning goes insane which can happen sporadically in product environment.
Cc: Paolo Bonzini <[email protected]> Cc: Radim Krčmář <[email protected]> Signed-off-by: Wanpeng Li <[email protected]> --- v1 -> v2: * retry max 10 times if adaptive tuning goes insane arch/x86/kvm/lapic.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 95affa5..bd0dbe5 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1538,6 +1538,7 @@ static inline void adjust_lapic_timer_advance(struct kvm_vcpu *vcpu, struct kvm_lapic *apic = vcpu->arch.apic; u32 timer_advance_ns = apic->lapic_timer.timer_advance_ns; u64 ns; + uint retry_count = 0; /* too early */ if (advance_expire_delta < 0) { @@ -1556,8 +1557,10 @@ static inline void adjust_lapic_timer_advance(struct kvm_vcpu *vcpu, if (abs(advance_expire_delta) < LAPIC_TIMER_ADVANCE_ADJUST_DONE) apic->lapic_timer.timer_advance_adjust_done = true; if (unlikely(timer_advance_ns > 5000)) { - timer_advance_ns = 0; - apic->lapic_timer.timer_advance_adjust_done = true; + timer_advance_ns = 1000; + apic->lapic_timer.timer_advance_adjust_done = false; + if (++retry_count > 10) + apic->lapic_timer.timer_advance_adjust_done = true; } apic->lapic_timer.timer_advance_ns = timer_advance_ns; } -- 1.8.3.1
