linux-kernel - [PATCH 1/3] KVM: Don't need to wakeup vCPU twice afer timer fire

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Message-Id: <1564572438-15518-1-git-send-email-wanpengli@tencent.com>
Date:   Wed, 31 Jul 2019 19:27:16 +0800
From:   Wanpeng Li <kernellwp@...il.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>
Subject: [PATCH 1/3] KVM: Don't need to wakeup vCPU twice afer timer fire

From: Wanpeng Li <wanpengli@...cent.com>

kvm_set_pending_timer() will take care to wake up the sleeping vCPU which 
has pending timer, don't need to check this in apic_timer_expired() again.

Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Radim Krčmář <rkrcmar@...hat.com>
Signed-off-by: Wanpeng Li <wanpengli@...cent.com>
---
 arch/x86/kvm/lapic.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 0aa1586..685d17c 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1548,7 +1548,6 @@ static void kvm_apic_inject_pending_timer_irqs(struct kvm_lapic *apic)
 static void apic_timer_expired(struct kvm_lapic *apic)
 {
 	struct kvm_vcpu *vcpu = apic->vcpu;
-	struct swait_queue_head *q = &vcpu->wq;
 	struct kvm_timer *ktimer = &apic->lapic_timer;
 
 	if (atomic_read(&apic->lapic_timer.pending))
@@ -1566,13 +1565,6 @@ static void apic_timer_expired(struct kvm_lapic *apic)
 
 	atomic_inc(&apic->lapic_timer.pending);
 	kvm_set_pending_timer(vcpu);
-
-	/*
-	 * For x86, the atomic_inc() is serialized, thus
-	 * using swait_active() is safe.
-	 */
-	if (swait_active(q))
-		swake_up_one(q);
 }
 
 static void start_sw_tscdeadline(struct kvm_lapic *apic)
-- 
2.7.4