* [PATCH 3/3] arm/arm64: KVM: vgic: Use non-atomic bitops
2013-11-22 23:57 [PATCH 0/3] arm/arm64: KVM: vgic: Various bugfixes and improvements Christoffer Dall
2013-11-22 23:57 ` [PATCH 1/3] arm/arm64: KVM: vgic: Bugfix in handle_mmio_cfg_reg Christoffer Dall
2013-11-22 23:57 ` [PATCH 2/3] arm/arm64: KVM: vgic: Bugfix in vgic_dispatch_sgi Christoffer Dall
@ 2013-11-22 23:57 ` Christoffer Dall
2 siblings, 0 replies; 4+ messages in thread
From: Christoffer Dall @ 2013-11-22 23:57 UTC (permalink / raw)
To: linux-arm-kernel
Change the use of atomic bitops to use the non-atomic versions. All
these operations are protected under a spinlock so using atomic
operations is simply a waste of cycles.
The test_and_clear_bit operations saves us ~500 cycles per world switch
on TC2 on average.
Changing the remaining bitops to their non-atomic versions saves us ~50
cycles over 100 repetitions of the average world-switch time of ~120,000
worls switches.
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
---
virt/kvm/arm/vgic.c | 42 +++++++++++++++++++++---------------------
1 file changed, 21 insertions(+), 21 deletions(-)
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index ecee766..8f52d41 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -128,9 +128,9 @@ static void vgic_bitmap_set_irq_val(struct vgic_bitmap *x, int cpuid,
}
if (val)
- set_bit(irq, reg);
+ __set_bit(irq, reg);
else
- clear_bit(irq, reg);
+ __clear_bit(irq, reg);
}
static unsigned long *vgic_bitmap_get_cpu_map(struct vgic_bitmap *x, int cpuid)
@@ -219,19 +219,19 @@ static void vgic_dist_irq_clear(struct kvm_vcpu *vcpu, int irq)
static void vgic_cpu_irq_set(struct kvm_vcpu *vcpu, int irq)
{
if (irq < VGIC_NR_PRIVATE_IRQS)
- set_bit(irq, vcpu->arch.vgic_cpu.pending_percpu);
+ __set_bit(irq, vcpu->arch.vgic_cpu.pending_percpu);
else
- set_bit(irq - VGIC_NR_PRIVATE_IRQS,
- vcpu->arch.vgic_cpu.pending_shared);
+ __set_bit(irq - VGIC_NR_PRIVATE_IRQS,
+ vcpu->arch.vgic_cpu.pending_shared);
}
static void vgic_cpu_irq_clear(struct kvm_vcpu *vcpu, int irq)
{
if (irq < VGIC_NR_PRIVATE_IRQS)
- clear_bit(irq, vcpu->arch.vgic_cpu.pending_percpu);
+ __clear_bit(irq, vcpu->arch.vgic_cpu.pending_percpu);
else
- clear_bit(irq - VGIC_NR_PRIVATE_IRQS,
- vcpu->arch.vgic_cpu.pending_shared);
+ __clear_bit(irq - VGIC_NR_PRIVATE_IRQS,
+ vcpu->arch.vgic_cpu.pending_shared);
}
static u32 mmio_data_read(struct kvm_exit_mmio *mmio, u32 mask)
@@ -466,9 +466,9 @@ static void vgic_set_target_reg(struct kvm *kvm, u32 val, int irq)
kvm_for_each_vcpu(c, vcpu, kvm) {
bmap = vgic_bitmap_get_shared_map(&dist->irq_spi_target[c]);
if (c == target)
- set_bit(irq + i, bmap);
+ __set_bit(irq + i, bmap);
else
- clear_bit(irq + i, bmap);
+ __clear_bit(irq + i, bmap);
}
}
}
@@ -812,14 +812,14 @@ static void vgic_update_state(struct kvm *kvm)
int c;
if (!dist->enabled) {
- set_bit(0, &dist->irq_pending_on_cpu);
+ __set_bit(0, &dist->irq_pending_on_cpu);
return;
}
kvm_for_each_vcpu(c, vcpu, kvm) {
if (compute_pending_for_cpu(vcpu)) {
pr_debug("CPU%d has pending interrupts\n", c);
- set_bit(c, &dist->irq_pending_on_cpu);
+ __set_bit(c, &dist->irq_pending_on_cpu);
}
}
}
@@ -848,7 +848,7 @@ static void vgic_retire_disabled_irqs(struct kvm_vcpu *vcpu)
if (!vgic_irq_is_enabled(vcpu, irq)) {
vgic_cpu->vgic_irq_lr_map[irq] = LR_EMPTY;
- clear_bit(lr, vgic_cpu->lr_used);
+ __clear_bit(lr, vgic_cpu->lr_used);
vgic_cpu->vgic_lr[lr] &= ~GICH_LR_STATE;
if (vgic_irq_is_active(vcpu, irq))
vgic_irq_clear_active(vcpu, irq);
@@ -893,7 +893,7 @@ static bool vgic_queue_irq(struct kvm_vcpu *vcpu, u8 sgi_source_id, int irq)
kvm_debug("LR%d allocated for IRQ%d %x\n", lr, irq, sgi_source_id);
vgic_cpu->vgic_lr[lr] = MK_LR_PEND(sgi_source_id, irq);
vgic_cpu->vgic_irq_lr_map[irq] = lr;
- set_bit(lr, vgic_cpu->lr_used);
+ __set_bit(lr, vgic_cpu->lr_used);
if (!vgic_irq_is_edge(vcpu, irq))
vgic_cpu->vgic_lr[lr] |= GICH_LR_EOI;
@@ -912,7 +912,7 @@ static bool vgic_queue_sgi(struct kvm_vcpu *vcpu, int irq)
for_each_set_bit(c, &sources, VGIC_MAX_CPUS) {
if (vgic_queue_irq(vcpu, c, irq))
- clear_bit(c, &sources);
+ __clear_bit(c, &sources);
}
dist->irq_sgi_sources[vcpu_id][irq] = sources;
@@ -920,7 +920,7 @@ static bool vgic_queue_sgi(struct kvm_vcpu *vcpu, int irq)
/*
* If the sources bitmap has been cleared it means that we
* could queue all the SGIs onto link registers (see the
- * clear_bit above), and therefore we are done with them in
+ * __clear_bit above), and therefore we are done with them in
* our emulated gic and can get rid of them.
*/
if (!sources) {
@@ -1003,7 +1003,7 @@ epilog:
* us. Claim we don't have anything pending. We'll
* adjust that if needed while exiting.
*/
- clear_bit(vcpu_id, &dist->irq_pending_on_cpu);
+ __clear_bit(vcpu_id, &dist->irq_pending_on_cpu);
}
}
@@ -1040,7 +1040,7 @@ static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
* Despite being EOIed, the LR may not have
* been marked as empty.
*/
- set_bit(lr, (unsigned long *)vgic_cpu->vgic_elrsr);
+ __set_bit(lr, (unsigned long *)vgic_cpu->vgic_elrsr);
vgic_cpu->vgic_lr[lr] &= ~GICH_LR_ACTIVE_BIT;
}
}
@@ -1069,7 +1069,7 @@ static void __kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
vgic_cpu->nr_lr) {
int irq;
- if (!test_and_clear_bit(lr, vgic_cpu->lr_used))
+ if (!__test_and_clear_bit(lr, vgic_cpu->lr_used))
continue;
irq = vgic_cpu->vgic_lr[lr] & GICH_LR_VIRTUALID;
@@ -1082,7 +1082,7 @@ static void __kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
pending = find_first_zero_bit((unsigned long *)vgic_cpu->vgic_elrsr,
vgic_cpu->nr_lr);
if (level_pending || pending < vgic_cpu->nr_lr)
- set_bit(vcpu->vcpu_id, &dist->irq_pending_on_cpu);
+ __set_bit(vcpu->vcpu_id, &dist->irq_pending_on_cpu);
}
void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
@@ -1200,7 +1200,7 @@ static bool vgic_update_irq_state(struct kvm *kvm, int cpuid,
if (level) {
vgic_cpu_irq_set(vcpu, irq_num);
- set_bit(cpuid, &dist->irq_pending_on_cpu);
+ __set_bit(cpuid, &dist->irq_pending_on_cpu);
}
out:
--
1.8.4.3
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