Re: [PATCH v1 1/4] virtio: introduce VIRTQUEUE_DEFUALT_SIZE instead of hardcoded constants

[Denis Plotnikov <dplotnikov@virtuozzo.com>]

On 30.01.2020 16:38, Michael S. Tsirkin wrote:
> On Wed, Jan 29, 2020 at 05:06:59PM +0300, Denis Plotnikov wrote:
>> Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
>
> I'm not sure what the point is. It's more or less an accident that
> these two devices share the queue size, this constance
> makes no sense to me.
Ok, then let's just make a separate queue length constant for each type.
(Will redo and send in the next series)
Thanks!

Denis
>
>> ---
>>   hw/block/virtio-blk.c      | 6 ++++--
>>   hw/scsi/virtio-scsi.c      | 5 +++--
>>   include/hw/virtio/virtio.h | 1 +
>>   3 files changed, 8 insertions(+), 4 deletions(-)
>>
>> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
>> index 09f46ed85f..72f935033f 100644
>> --- a/hw/block/virtio-blk.c
>> +++ b/hw/block/virtio-blk.c
>> @@ -914,7 +914,8 @@ static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config)
>>       memset(&blkcfg, 0, sizeof(blkcfg));
>>       virtio_stq_p(vdev, &blkcfg.capacity, capacity);
>>       virtio_stl_p(vdev, &blkcfg.seg_max,
>> -                 s->conf.seg_max_adjust ? s->conf.queue_size - 2 : 128 - 2);
>> +                 s->conf.seg_max_adjust ? s->conf.queue_size - 2 :
>> +                                          VIRTQUEUE_DEFAULT_SIZE - 2);
>>       virtio_stw_p(vdev, &blkcfg.geometry.cylinders, conf->cyls);
>>       virtio_stl_p(vdev, &blkcfg.blk_size, blk_size);
>>       virtio_stw_p(vdev, &blkcfg.min_io_size, conf->min_io_size / blk_size);
>> @@ -1272,7 +1273,8 @@ static Property virtio_blk_properties[] = {
>>       DEFINE_PROP_BIT("request-merging", VirtIOBlock, conf.request_merging, 0,
>>                       true),
>>       DEFINE_PROP_UINT16("num-queues", VirtIOBlock, conf.num_queues, 1),
>> -    DEFINE_PROP_UINT16("queue-size", VirtIOBlock, conf.queue_size, 128),
>> +    DEFINE_PROP_UINT16("queue-size", VirtIOBlock, conf.queue_size,
>> +                       VIRTQUEUE_DEFAULT_SIZE),
>>       DEFINE_PROP_BOOL("seg-max-adjust", VirtIOBlock, conf.seg_max_adjust, true),
>>       DEFINE_PROP_LINK("iothread", VirtIOBlock, conf.iothread, TYPE_IOTHREAD,
>>                        IOThread *),
>> diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
>> index 3b61563609..36f66046ae 100644
>> --- a/hw/scsi/virtio-scsi.c
>> +++ b/hw/scsi/virtio-scsi.c
>> @@ -660,7 +660,8 @@ static void virtio_scsi_get_config(VirtIODevice *vdev,
>>   
>>       virtio_stl_p(vdev, &scsiconf->num_queues, s->conf.num_queues);
>>       virtio_stl_p(vdev, &scsiconf->seg_max,
>> -                 s->conf.seg_max_adjust ? s->conf.virtqueue_size - 2 : 128 - 2);
>> +                 s->conf.seg_max_adjust ? s->conf.virtqueue_size - 2 :
>> +                                          VIRTQUEUE_DEFAULT_SIZE - 2);
>>       virtio_stl_p(vdev, &scsiconf->max_sectors, s->conf.max_sectors);
>>       virtio_stl_p(vdev, &scsiconf->cmd_per_lun, s->conf.cmd_per_lun);
>>       virtio_stl_p(vdev, &scsiconf->event_info_size, sizeof(VirtIOSCSIEvent));
>> @@ -965,7 +966,7 @@ static void virtio_scsi_device_unrealize(DeviceState *dev, Error **errp)
>>   static Property virtio_scsi_properties[] = {
>>       DEFINE_PROP_UINT32("num_queues", VirtIOSCSI, parent_obj.conf.num_queues, 1),
>>       DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSI,
>> -                                         parent_obj.conf.virtqueue_size, 128),
>> +                       parent_obj.conf.virtqueue_size, VIRTQUEUE_DEFAULT_SIZE),
>>       DEFINE_PROP_BOOL("seg_max_adjust", VirtIOSCSI,
>>                         parent_obj.conf.seg_max_adjust, true),
>>       DEFINE_PROP_UINT32("max_sectors", VirtIOSCSI, parent_obj.conf.max_sectors,
>> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
>> index b69d517496..a66ea2368b 100644
>> --- a/include/hw/virtio/virtio.h
>> +++ b/include/hw/virtio/virtio.h
>> @@ -48,6 +48,7 @@ size_t virtio_feature_get_config_size(VirtIOFeature *features,
>>   typedef struct VirtQueue VirtQueue;
>>   
>>   #define VIRTQUEUE_MAX_SIZE 1024
>> +#define VIRTQUEUE_DEFAULT_SIZE 128
>>   
>>   typedef struct VirtQueueElement
>>   {
>> -- 
>> 2.17.0