Messages in this thread Patch in this message | | | From | Nitesh Narayan Lal <> | Subject | [Patch v1 1/2] KVM: remember position in kvm->vcpus array | Date | Wed, 6 Nov 2019 08:36:37 -0500 |
| |
From: Radim Krčmář <rkrcmar@redhat.com>
Fetching an index for any vcpu in kvm->vcpus array by traversing the entire array everytime is costly. This patch remembers the position of each vcpu in kvm->vcpus array by storing it in vcpus_idx under kvm_vcpu structure.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com> --- include/linux/kvm_host.h | 11 +++-------- virt/kvm/kvm_main.c | 5 ++++- 2 files changed, 7 insertions(+), 9 deletions(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 719fc3e..31c4fde 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -266,7 +266,8 @@ struct kvm_vcpu { struct preempt_notifier preempt_notifier; #endif int cpu; - int vcpu_id; + int vcpu_id; /* id given by userspace at creation */ + int vcpus_idx; /* index in kvm->vcpus array */ int srcu_idx; int mode; u64 requests; @@ -571,13 +572,7 @@ static inline struct kvm_vcpu *kvm_get_vcpu_by_id(struct kvm *kvm, int id) static inline int kvm_vcpu_get_idx(struct kvm_vcpu *vcpu) { - struct kvm_vcpu *tmp; - int idx; - - kvm_for_each_vcpu(idx, tmp, vcpu->kvm) - if (tmp == vcpu) - return idx; - BUG(); + return vcpu->vcpus_idx; } #define kvm_for_each_memslot(memslot, slots) \ diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 67ef3f2..24ab711 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -2673,7 +2673,10 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) goto unlock_vcpu_destroy; } - BUG_ON(kvm->vcpus[atomic_read(&kvm->online_vcpus)]); + vcpu->vcpus_idx = atomic_read(&kvm->online_vcpus); + + BUG_ON(kvm->vcpus[vcpu->vcpus_idx]); + /* Now it's all set up, let userspace reach it */ kvm_get_kvm(kvm); -- 1.8.3.1
| |