From 91ab933f7514fc0fb42b77dc6d128c450baeae0b Mon Sep 17 00:00:00 2001 From: Li RongQing Date: Wed, 6 Apr 2022 19:25:02 +0800 Subject: [PATCH] KVM: VMX: clean up pi_wakeup_handler Passing per_cpu() to list_for_each_entry() causes the macro to be evaluated N+1 times for N sleeping vCPUs. This is a very small inefficiency, and the code is cleaner if the address of the per-CPU variable is loaded earlier. Do this for both the list and the spinlock. Signed-off-by: Li RongQing Message-Id: <1649244302-6777-1-git-send-email-lirongqing@baidu.com> Reviewed-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/posted_intr.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/vmx/posted_intr.c b/arch/x86/kvm/vmx/posted_intr.c index 37d0bff..07e5fcf 100644 --- a/arch/x86/kvm/vmx/posted_intr.c +++ b/arch/x86/kvm/vmx/posted_intr.c @@ -202,16 +202,17 @@ void vmx_vcpu_pi_put(struct kvm_vcpu *vcpu) void pi_wakeup_handler(void) { int cpu = smp_processor_id(); + struct list_head *wakeup_list = &per_cpu(wakeup_vcpus_on_cpu, cpu); + raw_spinlock_t *spinlock = &per_cpu(wakeup_vcpus_on_cpu_lock, cpu); struct vcpu_vmx *vmx; - raw_spin_lock(&per_cpu(wakeup_vcpus_on_cpu_lock, cpu)); - list_for_each_entry(vmx, &per_cpu(wakeup_vcpus_on_cpu, cpu), - pi_wakeup_list) { + raw_spin_lock(spinlock); + list_for_each_entry(vmx, wakeup_list, pi_wakeup_list) { if (pi_test_on(&vmx->pi_desc)) kvm_vcpu_wake_up(&vmx->vcpu); } - raw_spin_unlock(&per_cpu(wakeup_vcpus_on_cpu_lock, cpu)); + raw_spin_unlock(spinlock); } void __init pi_init_cpu(int cpu) -- 2.7.4