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KVM: LAPIC: Retry tune per-vCPU timer_advance_ns if adaptive tuning goes insane 

Retry tune per-vCPU timer_advance_ns if adaptive tuning goes insane which
can happen sporadically in product environment.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
alistair/sunxi64-5.4-dsi
Wanpeng Li 2019-07-05 23:23:42 +08:00 committed by Paolo Bonzini
parent 01402cf810
commit 548f7fb222
1 changed files with 4 additions and 3 deletions
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7
arch/x86/kvm/lapic.c
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@ -71,6 +71,7 @@
#define X2APIC_BROADCAST 0xFFFFFFFFul
#define LAPIC_TIMER_ADVANCE_ADJUST_DONE 100
#define LAPIC_TIMER_ADVANCE_ADJUST_INIT 1000
/* step-by-step approximation to mitigate fluctuation */
#define LAPIC_TIMER_ADVANCE_ADJUST_STEP 8
@ -1546,8 +1547,8 @@ 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 = LAPIC_TIMER_ADVANCE_ADJUST_INIT;
apic->lapic_timer.timer_advance_adjust_done = false;
}
apic->lapic_timer.timer_advance_ns = timer_advance_ns;
}
@ -2344,7 +2345,7 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu, int timer_advance_ns)
HRTIMER_MODE_ABS_PINNED);
apic->lapic_timer.timer.function = apic_timer_fn;
if (timer_advance_ns == -1) {
apic->lapic_timer.timer_advance_ns = 1000;
apic->lapic_timer.timer_advance_ns = LAPIC_TIMER_ADVANCE_ADJUST_INIT;
apic->lapic_timer.timer_advance_adjust_done = false;
} else {
apic->lapic_timer.timer_advance_ns = timer_advance_ns;