Re: [Qemu-devel] [PATCH V4 09/19] virito: introduce bus specific queue limit

[Jason Wang <jasowang@redhat.com>]

On Fri, Mar 20, 2015 at 6:20 PM, Cornelia Huck 
<cornelia.huck@de.ibm.com> wrote:
> On Wed, 18 Mar 2015 17:34:59 +0800
> Jason Wang <jasowang@redhat.com> wrote:
> 
> Typo in subject: s/virito/virtio/

Will correct this.
> 
> 
>>  This patch introduces a bus specific queue limitation. It will be
>>  useful for increasing the limit for one of the bus without 
>> disturbing
>>  other buses.
>>  
>>  Cc: Michael S. Tsirkin <mst@redhat.com>
>>  Cc: Alexander Graf <agraf@suse.de>
>>  Cc: Richard Henderson <rth@twiddle.net>
>>  Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
>>  Cc: Christian Borntraeger <borntraeger@de.ibm.com>
>>  Cc: Paolo Bonzini <pbonzini@redhat.com>
>>  Signed-off-by: Jason Wang <jasowang@redhat.com>
>>  ---
>>   hw/char/virtio-serial-bus.c    |  2 +-
>>   hw/net/virtio-net.c            |  4 ++--
>>   hw/s390x/s390-virtio-bus.c     |  1 +
>>   hw/s390x/virtio-ccw.c          |  1 +
>>   hw/scsi/virtio-scsi.c          |  4 ++--
>>   hw/virtio/virtio-mmio.c        |  1 +
>>   hw/virtio/virtio-pci.c         |  1 +
>>   hw/virtio/virtio.c             | 40 
>> +++++++++++++++++++++++++---------------
>>   include/hw/virtio/virtio-bus.h |  1 +
>>   include/hw/virtio/virtio.h     |  1 +
>>   10 files changed, 36 insertions(+), 20 deletions(-)
> 
>>  diff --git a/hw/s390x/s390-virtio-bus.c b/hw/s390x/s390-virtio-bus.c
>>  index 047c963..2b41e32 100644
>>  --- a/hw/s390x/s390-virtio-bus.c
>>  +++ b/hw/s390x/s390-virtio-bus.c
>>  @@ -715,6 +715,7 @@ static void 
>> virtio_s390_bus_class_init(ObjectClass *klass, void *data)
>>       bus_class->max_dev = 1;
>>       k->notify = virtio_s390_notify;
>>       k->get_features = virtio_s390_get_features;
>>  +    k->queue_max = VIRTIO_PCI_QUEUE_MAX;
> 
> I'm wondering whether we should initialize queue_max to smth like
> VIRTIO_QUEUE_MAX_DEFAULT (== 64) in virtio-bus.c instead and have the
> individual classes override that value once they want to use a
> different value?

May work now, but consider in the future, each transport will finally 
have their own limitation, so VIRTIO_QUEUE_MAX_DEFAULT will finally be 
removed some day.
> 
> 
> But I'm fine with this patch as it stands as well.

Thanks, so I will keep this patch as is.
> 
>>   }
>