On Tue, Jul 14, 2009 at 05:30:45PM +0300, Gleb Natapov wrote:
> Use gsi indexed array instead of scanning all entries on each interrupt
> injection. Also maintain back mapping from irqchip/pin to gsi to speedup
> interrupt acknowledgment notifications.
>
> Signed-off-by: Gleb Natapov <gleb@xxxxxxxxxx>
> ---
> include/linux/kvm_host.h | 11 ++++++-
> virt/kvm/irq_comm.c | 62 ++++++++++++++++++++++++++++-----------------
> 2 files changed, 47 insertions(+), 26 deletions(-)
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index aa64d0d..ae6cbf1 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -128,7 +128,14 @@ struct kvm_kernel_irq_routing_entry {
> } irqchip;
> struct msi_msg msi;
> };
> - struct list_head link;
> + struct hlist_node link;
> +};
> +
> +struct kvm_irq_routing_table {
> + int chip[3][KVM_IOAPIC_NUM_PINS];
> + struct kvm_kernel_irq_routing_entry *rt_entries;
> + u32 max_gsi;
> + struct hlist_head map[0];
> };
>
> struct kvm {
> @@ -165,7 +172,7 @@ struct kvm {
> #endif
>
> #ifdef CONFIG_HAVE_KVM_IRQCHIP
> - struct kvm_kernel_irq_routing_entry *irq_routing;
> + struct kvm_irq_routing_table *irq_routing;
> spinlock_t irq_routing_lock;
> struct hlist_head mask_notifier_list;
> struct hlist_head irq_ack_notifier_list;
> diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
> index c54a28b..da643d4 100644
> --- a/virt/kvm/irq_comm.c
> +++ b/virt/kvm/irq_comm.c
> @@ -125,6 +125,8 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
> struct kvm_kernel_irq_routing_entry *e;
> unsigned long *irq_state, sig_level;
> int ret = -1;
> + struct kvm_irq_routing_table *irq_rt;
> + struct hlist_node *n;
>
> trace_kvm_set_irq(irq, level, irq_source_id);
>
> @@ -147,14 +149,13 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
> * writes to the unused one.
> */
> rcu_read_lock();
> - for (e = rcu_dereference(kvm->irq_routing); e && e->set; e++) {
> - if (e->gsi == irq) {
> - int r = e->set(e, kvm, sig_level);
> - if (r < 0)
> - continue;
> + irq_rt = rcu_dereference(kvm->irq_routing);
> + hlist_for_each_entry(e, n, &irq_rt->map[irq], link) {
> + int r = e->set(e, kvm, sig_level);
> + if (r < 0)
> + continue;
>
> - ret = r + ((ret < 0) ? 0 : ret);
> - }
> + ret = r + ((ret < 0) ? 0 : ret);
> }
> rcu_read_unlock();
> return ret;
> @@ -162,21 +163,16 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
>
> void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
> {
> - struct kvm_kernel_irq_routing_entry *e;
> struct kvm_irq_ack_notifier *kian;
> struct hlist_node *n;
> - unsigned gsi = pin;
> + unsigned gsi;
>
> trace_kvm_ack_irq(irqchip, pin);
>
> rcu_read_lock();
> - for (e = rcu_dereference(kvm->irq_routing); e && e->set; e++) {
> - if (e->irqchip.irqchip == irqchip &&
> - e->irqchip.pin == pin) {
> - gsi = e->gsi;
> - break;
> - }
> - }
> + gsi = rcu_dereference(kvm->irq_routing)->chip[irqchip][pin];
> + if (gsi == -1)
> + gsi = pin;
>
> hlist_for_each_entry_rcu(kian, n, &kvm->irq_ack_notifier_list, link)
> if (kian->gsi == gsi)
> @@ -277,7 +273,8 @@ void kvm_free_irq_routing(struct kvm *kvm)
> kfree(kvm->irq_routing);
> }
>
> -static int setup_routing_entry(struct kvm_kernel_irq_routing_entry *e,
> +static int setup_routing_entry(struct kvm_irq_routing_table *rt,
> + struct kvm_kernel_irq_routing_entry *e,
> const struct kvm_irq_routing_entry *ue)
> {
> int r = -EINVAL;
> @@ -303,6 +300,7 @@ static int setup_routing_entry(struct kvm_kernel_irq_routing_entry *e,
> }
> e->irqchip.irqchip = ue->u.irqchip.irqchip;
> e->irqchip.pin = ue->u.irqchip.pin + delta;
> + rt->chip[ue->u.irqchip.irqchip][e->irqchip.pin] = ue->gsi;
> break;
> case KVM_IRQ_ROUTING_MSI:
> e->set = kvm_set_msi;
> @@ -313,6 +311,8 @@ static int setup_routing_entry(struct kvm_kernel_irq_routing_entry *e,
> default:
> goto out;
> }
> +
> + hlist_add_head(&e->link, &rt->map[e->gsi]);
> r = 0;
> out:
> return r;
> @@ -324,23 +324,37 @@ int kvm_set_irq_routing(struct kvm *kvm,
> unsigned nr,
> unsigned flags)
> {
> - struct kvm_kernel_irq_routing_entry *new, *old;
> - unsigned i;
> + struct kvm_irq_routing_table *new, *old;
> + u32 i, j, max_gsi = 0;
> int r;
>
> - /* last elemet is left zeored and indicates the end of the array */
> - new = kzalloc(sizeof(*new) * (nr + 1), GFP_KERNEL);
> + for (i = 0; i < nr; ++i) {
> + if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES)
> + return -EINVAL;
> + max_gsi = max(max_gsi, ue[i].gsi);
> + }
> +
> + max_gsi += 1;
> +
> + new = kzalloc(sizeof(*new) + (max_gsi * sizeof(struct hlist_head)) +
> + (nr * sizeof(struct kvm_kernel_irq_routing_entry)),
> + GFP_KERNEL);
Why don't you allocate the hlist_head's and the routing entries
separately?
>
> if (!new)
> return -ENOMEM;
>
> + new->rt_entries = (void *)&new->map[max_gsi];
> +
> + new->max_gsi = max_gsi;
> + for (i = 0; i < 3; i++)
> + for (j = 0; j < KVM_IOAPIC_NUM_PINS; j++)
> + new->chip[i][j] = -1;
> +
Should use something else instead of 3. Maybe dynamic for multiple
IOAPIC's support (but you can argue thats another problem).
> for (i = 0; i < nr; ++i) {
> r = -EINVAL;
> - if (ue->gsi >= KVM_MAX_IRQ_ROUTES)
> - goto out;
> if (ue->flags)
> goto out;
> - r = setup_routing_entry(new + i, ue);
> + r = setup_routing_entry(new, &new->rt_entries[i], ue);
> if (r)
> goto out;
> ++ue;
> --
> 1.6.2.1
>
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