From: Avi Kivity <avi@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>, kvm@vger.kernel.org
Subject: [PATCH v2 2/3] KVM: Optimize vcpu->requests slow path slightly
Date: Sun, 20 May 2012 16:49:27 +0300 [thread overview]
Message-ID: <1337521768-14182-3-git-send-email-avi@redhat.com> (raw)
In-Reply-To: <1337521768-14182-1-git-send-email-avi@redhat.com>
Instead of using a atomic operation per active request, use just one
to get all requests at once, then check them with local ops. This
probably isn't any faster, since simultaneous requests are rare, but
it does reduce code size.
Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/x86/kvm/x86.c | 33 ++++++++++++++++++---------------
1 file changed, 18 insertions(+), 15 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 953e692..c0209eb 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5232,55 +5232,58 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
bool req_int_win = !irqchip_in_kernel(vcpu->kvm) &&
vcpu->run->request_interrupt_window;
bool req_immediate_exit = 0;
+ ulong reqs;
if (unlikely(req_int_win))
kvm_make_request(KVM_REQ_EVENT, vcpu);
if (vcpu->requests) {
- if (kvm_check_request(KVM_REQ_MMU_RELOAD, vcpu))
+ reqs = xchg(&vcpu->requests, 0UL);
+
+ if (test_bit(KVM_REQ_MMU_RELOAD, &reqs))
kvm_mmu_unload(vcpu);
- if (kvm_check_request(KVM_REQ_MIGRATE_TIMER, vcpu))
+ if (test_bit(KVM_REQ_MIGRATE_TIMER, &reqs))
__kvm_migrate_timers(vcpu);
- if (kvm_check_request(KVM_REQ_CLOCK_UPDATE, vcpu)) {
+ if (test_bit(KVM_REQ_CLOCK_UPDATE, &reqs)) {
r = kvm_guest_time_update(vcpu);
if (unlikely(r))
goto out;
}
- if (kvm_check_request(KVM_REQ_MMU_SYNC, vcpu))
+ if (test_bit(KVM_REQ_MMU_SYNC, &reqs))
kvm_mmu_sync_roots(vcpu);
- if (kvm_check_request(KVM_REQ_TLB_FLUSH, vcpu))
+ if (test_bit(KVM_REQ_TLB_FLUSH, &reqs))
kvm_x86_ops->tlb_flush(vcpu);
- if (kvm_check_request(KVM_REQ_REPORT_TPR_ACCESS, vcpu)) {
+ if (test_bit(KVM_REQ_REPORT_TPR_ACCESS, &reqs)) {
vcpu->run->exit_reason = KVM_EXIT_TPR_ACCESS;
r = 0;
goto out;
}
- if (kvm_check_request(KVM_REQ_TRIPLE_FAULT, vcpu)) {
+ if (test_bit(KVM_REQ_TRIPLE_FAULT, &reqs)) {
vcpu->run->exit_reason = KVM_EXIT_SHUTDOWN;
r = 0;
goto out;
}
- if (kvm_check_request(KVM_REQ_DEACTIVATE_FPU, vcpu)) {
+ if (test_bit(KVM_REQ_DEACTIVATE_FPU, &reqs)) {
vcpu->fpu_active = 0;
kvm_x86_ops->fpu_deactivate(vcpu);
}
- if (kvm_check_request(KVM_REQ_APF_HALT, vcpu)) {
+ if (test_bit(KVM_REQ_APF_HALT, &reqs)) {
/* Page is swapped out. Do synthetic halt */
vcpu->arch.apf.halted = true;
r = 1;
goto out;
}
- if (kvm_check_request(KVM_REQ_STEAL_UPDATE, vcpu))
+ if (test_bit(KVM_REQ_STEAL_UPDATE, &reqs))
record_steal_time(vcpu);
- if (kvm_check_request(KVM_REQ_NMI, vcpu))
+ if (test_bit(KVM_REQ_NMI, &reqs))
process_nmi(vcpu);
req_immediate_exit =
- kvm_check_request(KVM_REQ_IMMEDIATE_EXIT, vcpu);
- if (kvm_check_request(KVM_REQ_PMU, vcpu))
+ test_bit(KVM_REQ_IMMEDIATE_EXIT, &reqs);
+ if (test_bit(KVM_REQ_PMU, &reqs))
kvm_handle_pmu_event(vcpu);
- if (kvm_check_request(KVM_REQ_PMI, vcpu))
+ if (test_bit(KVM_REQ_PMI, &reqs))
kvm_deliver_pmi(vcpu);
- if (kvm_check_request(KVM_REQ_EVENT, vcpu)) {
+ if (test_bit(KVM_REQ_EVENT, &reqs)) {
inject_pending_event(vcpu);
/* enable NMI/IRQ window open exits if needed */
--
1.7.10.1
next prev parent reply other threads:[~2012-05-20 13:49 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-20 13:49 [PATCH v2 0/3] Minor vcpu->requests improvements Avi Kivity
2012-05-20 13:49 ` [PATCH v2 1/3] KVM: Simplify KVM_REQ_EVENT/req_int_win handling Avi Kivity
2012-05-20 13:49 ` Avi Kivity [this message]
2012-05-30 20:03 ` [PATCH v2 2/3] KVM: Optimize vcpu->requests slow path slightly Marcelo Tosatti
2012-05-31 9:27 ` Avi Kivity
2012-06-02 0:23 ` Marcelo Tosatti
2012-05-20 13:49 ` [PATCH v2 3/3] KVM: Move mmu reload out of line Avi Kivity
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