On 04/06/13 15:48, Bob(ERC) wrote:
>
> improve loop performance of vgic_get_target_reg and make it
> consistent with vgic_set_target_reg. In current implementation,
> vgic only sets and distributes interrupts to specific target cpu
> interface.
>
> Signed-off-by: Bo Zhao <zhaobo@xxxxxxxxxx>
> ---
> arch/arm/kvm/vgic.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/kvm/vgic.c b/arch/arm/kvm/vgic.c
> index 17c5ac7..e6eb36c 100644
> --- a/arch/arm/kvm/vgic.c
> +++ b/arch/arm/kvm/vgic.c
> @@ -439,11 +439,14 @@ static u32 vgic_get_target_reg(struct kvm *kvm, int irq)
>
> irq -= VGIC_NR_PRIVATE_IRQS;
>
> - kvm_for_each_vcpu(c, vcpu, kvm) {
> - bmap = vgic_bitmap_get_shared_map(&dist->irq_spi_target[c]);
> - for (i = 0; i < GICD_IRQS_PER_ITARGETSR; i++)
> - if (test_bit(irq + i, bmap))
> + for (i = 0; i < GICD_IRQS_PER_ITARGETSR; i++) {
> + kvm_for_each_vcpu(c, vcpu, kvm) {
> + bmap = vgic_bitmap_get_shared_map(&dist->irq_spi_target[c]);
> + if (test_bit(irq + i, bmap)) {
> val |= 1 << (c + i * 8);
> + break;
> + }
> + }
> }
>
> return val;
>
I'm not sure that's much of an improvement.
How about this (fully untested) patch instead:
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 9f5817d..5d9cf1a 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -432,19 +432,13 @@ static bool handle_mmio_priority_reg(struct kvm_vcpu *vcpu,
static u32 vgic_get_target_reg(struct kvm *kvm, int irq)
{
struct vgic_dist *dist = &kvm->arch.vgic;
- struct kvm_vcpu *vcpu;
- int i, c;
- unsigned long *bmap;
+ int i;
u32 val = 0;
irq -= VGIC_NR_PRIVATE_IRQS;
- kvm_for_each_vcpu(c, vcpu, kvm) {
- bmap = vgic_bitmap_get_shared_map(&dist->irq_spi_target[c]);
- for (i = 0; i < GICD_IRQS_PER_ITARGETSR; i++)
- if (test_bit(irq + i, bmap))
- val |= 1 << (c + i * 8);
- }
+ for (i = 0; i < GICD_IRQS_PER_ITARGETSR; i++)
+ val |= 1 << (dist->irq_spi_cpu[irq + i] + i * 8);
return val;
}
Cheers,
M.
--
Jazz is not dead. It just smells funny...
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