Jetpack/kernel/kernel-4.9/rt-patches/0270-KVM-lapic-mark-LAPIC-t...

32 lines
1.0 KiB
Diff

From 5410534dbd1a702bac2e4c6af7104a61e4681217 Mon Sep 17 00:00:00 2001
From: Marcelo Tosatti <mtosatti@redhat.com>
Date: Wed, 8 Apr 2015 20:33:25 -0300
Subject: [PATCH 270/352] KVM: lapic: mark LAPIC timer handler as irqsafe
Since lapic timer handler only wakes up a simple waitqueue,
it can be executed from hardirq context.
Reduces average cyclictest latency by 3us.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
arch/x86/kvm/lapic.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 69a81a7..fdb8dca 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1970,6 +1970,7 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu)
hrtimer_init(&apic->lapic_timer.timer, CLOCK_MONOTONIC,
HRTIMER_MODE_ABS_PINNED);
apic->lapic_timer.timer.function = apic_timer_fn;
+ apic->lapic_timer.timer.irqsafe = 1;
/*
* APIC is created enabled. This will prevent kvm_lapic_set_base from
--
2.7.4