Hi,
I think you missed a cleanup_srcu_struct(&kvm->irq_srcu) in kvm_destroy_vm().
On Mon, May 5, 2014 at 10:26 PM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
> Il 05/05/2014 16:21, Christian Borntraeger ha scritto:
>
>> On 28/04/14 18:39, Paolo Bonzini wrote:
>>>
>>> From: Christian Borntraeger <borntraeger@xxxxxxxxxx>
>>
>>
>> Given all your work, What about From: Paolo Bonzini <pbonzini@xxxxxxxxxx>
>> plus "Based on an inital patch from Christian Borntraeger"
>
>
> No big deal, I don't care about authorship that much.
>
>
>>> @@ -221,17 +225,18 @@ irqfd_wakeup(wait_queue_t *wait, unsigned mode, int
>>> sync, void *key)
>>> unsigned long flags = (unsigned long)key;
>>> struct kvm_kernel_irq_routing_entry *irq;
>>> struct kvm *kvm = irqfd->kvm;
>>> + int idx;
>>>
>>> if (flags & POLLIN) {
>>> - rcu_read_lock();
>>> - irq = rcu_dereference(irqfd->irq_entry);
>>> + idx = srcu_read_lock(&kvm->irq_srcu);
>>> + irq = srcu_dereference(irqfd->irq_entry, &kvm->irq_srcu);
>>> /* An event has been signaled, inject an interrupt */
>>> if (irq)
>>> kvm_set_msi(irq, kvm,
>>> KVM_USERSPACE_IRQ_SOURCE_ID, 1,
>>> false);
>>> else
>>> schedule_work(&irqfd->inject);
>>> - rcu_read_unlock();
>>> + srcu_read_unlock(&kvm->irq_srcu, idx);
>>> }
>>>
>>> if (flags & POLLHUP) {
>>> @@ -363,7 +368,7 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd
>>> *args)
>>> }
>>>
>>> list_add_rcu(&irqfd->resampler_link,
>>> &irqfd->resampler->list);
>>> - synchronize_rcu();
>>> + synchronize_srcu(&kvm->irq_srcu);
>>
>>
>> No idea what resampler is, can this become time critical as well - iow do
>> we need expedited here?
>
>
> It's for level-triggered interrupts. I decided that if synchronize_rcu was
> good enough before, synchronize_srcu will do after the patch.
>
>
>>> @@ -85,7 +86,7 @@ void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
>>> mutex_lock(&kvm->irq_lock);
>>> hlist_del_init_rcu(&kian->link);
>>> mutex_unlock(&kvm->irq_lock);
>>> - synchronize_rcu();
>>> + synchronize_srcu_expedited(&kvm->irq_srcu);
>>
>>
>> Hmm, looks like all callers are slow path (shutdown, deregister assigned
>> dev). Couldnt
>> we use the non expedited variant?
>
>
> ... but I have screwed up this one. Thanks, I'll change it.
>
>
>>> r = kvm_arch_init_vm(kvm, type);
>>> if (r)
>>> - goto out_err_nodisable;
>>> + goto out_err_no_disable;
>>>
>>> r = hardware_enable_all();
>>> if (r)
>>> - goto out_err_nodisable;
>>> + goto out_err_no_disable;
>>>
>>> #ifdef CONFIG_HAVE_KVM_IRQCHIP
>>> INIT_HLIST_HEAD(&kvm->mask_notifier_list);
>>> @@ -473,10 +473,12 @@ static struct kvm *kvm_create_vm(unsigned long
>>> type)
>>> r = -ENOMEM;
>>> kvm->memslots = kzalloc(sizeof(struct kvm_memslots), GFP_KERNEL);
>>> if (!kvm->memslots)
>>> - goto out_err_nosrcu;
>>> + goto out_err_no_srcu;
>>> kvm_init_memslots_id(kvm);
>>> if (init_srcu_struct(&kvm->srcu))
>>> - goto out_err_nosrcu;
>>> + goto out_err_no_srcu;
>>> + if (init_srcu_struct(&kvm->irq_srcu))
>>> + goto out_err_no_irq_srcu;
>>> for (i = 0; i < KVM_NR_BUSES; i++) {
>>> kvm->buses[i] = kzalloc(sizeof(struct kvm_io_bus),
>>> GFP_KERNEL);
>>> @@ -505,10 +507,12 @@ static struct kvm *kvm_create_vm(unsigned long
>>> type)
>>> return kvm;
>>>
>>> out_err:
>>> + cleanup_srcu_struct(&kvm->irq_srcu);
>>> +out_err_no_irq_srcu:
>>> cleanup_srcu_struct(&kvm->srcu);
>>> -out_err_nosrcu:
>>> +out_err_no_srcu:
>>> hardware_disable_all();
>>> -out_err_nodisable:
>>> +out_err_no_disable:
>>
>>
>>
>> the patch would be smaller without this change, but it makes the naming
>> more consistent, so ok.
>
>
> Yeah, out_err_noirq_srcu or out_err_noirqsrcu are both very ugly.
>
> Thanks for the review, I'm making the small change to remove expedited and
> applying to kvm/queue.
>
> Paolo
>
>
>>
>>> for (i = 0; i < KVM_NR_BUSES; i++)
>>> kfree(kvm->buses[i]);
>>> kfree(kvm->memslots);
>>>
>>
>
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