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| author |   Li RongQing <lirongqing@baidu.com> | 2022-04-06 19:25:02 +0800 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2022-05-12 09:51:40 -0400 |
| commit | 91ab933f7514fc0fb42b77dc6d128c450baeae0b (patch) | |
| tree | aad485cbd1d8089495bdb48365285b4575ca0fbe /arch/x86/kvm/vmx/posted_intr.c | |
| parent | KVM: x86: fix typo in __try_cmpxchg_user causing non-atomicness (diff) | |
| download | wireguard-linux-91ab933f7514fc0fb42b77dc6d128c450baeae0b.tar.xz wireguard-linux-91ab933f7514fc0fb42b77dc6d128c450baeae0b.zip | |
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 <lirongqing@baidu.com>
Message-Id: <1649244302-6777-1-git-send-email-lirongqing@baidu.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/vmx/posted_intr.c')
| -rw-r--r-- | arch/x86/kvm/vmx/posted_intr.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/arch/x86/kvm/vmx/posted_intr.c b/arch/x86/kvm/vmx/posted_intr.c index 37d0bfff269d..07e5fcf5a5aa 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) |