From 548f7fb22234c6fe13c64459059fbd42058953c4 Mon Sep 17 00:00:00 2001 From: Wanpeng Li Date: Fri, 5 Jul 2019 23:23:42 +0800 Subject: [PATCH] KVM: LAPIC: Retry tune per-vCPU timer_advance_ns if adaptive tuning goes insane MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Retry tune per-vCPU timer_advance_ns if adaptive tuning goes insane which can happen sporadically in product environment. Cc: Paolo Bonzini Cc: Radim Krčmář Signed-off-by: Wanpeng Li Signed-off-by: Paolo Bonzini --- arch/x86/kvm/lapic.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index e4227ceab0c6..e1a2e2d467ca 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -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;