diff options
| author |   Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2019-07-26 20:30:55 +0200 |
|---|---|---|
| committer |   Thomas Gleixner <tglx@linutronix.de> | 2019-08-01 20:51:20 +0200 |
| commit | 2c0d278f3293fc59da0d183075415ca1e8c93b40 (patch) | |
| tree | 214f5bb35b62a158046d3a7efd8636d96c9b90a5 | |
| parent | watchdog: Mark watchdog_hrtimer to expire in hard interrupt context (diff) | |
| download | linux-dev-2c0d278f3293fc59da0d183075415ca1e8c93b40.tar.xz linux-dev-2c0d278f3293fc59da0d183075415ca1e8c93b40.zip | |
KVM: LAPIC: Mark hrtimer to expire in hard interrupt context
On PREEMPT_RT enabled kernels unmarked hrtimers are moved into soft
interrupt expiry mode by default.
While that's not a functional requirement for the KVM local APIC timer
emulation, it's a latency issue which can be avoided by marking the timer
so hard interrupt context expiry is enforced.
No functional change.
[ tglx: Split out from larger combo patch. Add changelog. ]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190726185753.363363474@linutronix.de
| -rw-r--r-- | arch/x86/kvm/lapic.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 0aa158657f20..b9e516099d07 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1601,7 +1601,7 @@ static void start_sw_tscdeadline(struct kvm_lapic *apic) likely(ns > apic->lapic_timer.timer_advance_ns)) { expire = ktime_add_ns(now, ns); expire = ktime_sub_ns(expire, ktimer->timer_advance_ns); - hrtimer_start(&ktimer->timer, expire, HRTIMER_MODE_ABS); + hrtimer_start(&ktimer->timer, expire, HRTIMER_MODE_ABS_HARD); } else apic_timer_expired(apic); @@ -2302,7 +2302,7 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu, int timer_advance_ns) apic->vcpu = vcpu; hrtimer_init(&apic->lapic_timer.timer, CLOCK_MONOTONIC, - HRTIMER_MODE_ABS); + HRTIMER_MODE_ABS_HARD); apic->lapic_timer.timer.function = apic_timer_fn; if (timer_advance_ns == -1) { apic->lapic_timer.timer_advance_ns = LAPIC_TIMER_ADVANCE_ADJUST_INIT; @@ -2487,7 +2487,7 @@ void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu) timer = &vcpu->arch.apic->lapic_timer.timer; if (hrtimer_cancel(timer)) - hrtimer_start_expires(timer, HRTIMER_MODE_ABS); + hrtimer_start_expires(timer, HRTIMER_MODE_ABS_HARD); } /* |