On Mon, Mar 23, 2015 at 2:06 PM, K. Y. Srinivasan <kys@xxxxxxxxxxxxx> wrote:
> Size the queue depth based on the ringbuffer size. Also accomodate for the
> fact that we could have multiple channels (ringbuffers) per adaptor.
>
> Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
> Reviewed-by: Long Li <longli@xxxxxxxxxxxxx>
> ---
> drivers/scsi/storvsc_drv.c | 27 ++++++++++++++++-----------
> 1 files changed, 16 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
> index 27fe850..5a12897 100644
> --- a/drivers/scsi/storvsc_drv.c
> +++ b/drivers/scsi/storvsc_drv.c
> @@ -309,10 +309,15 @@ enum storvsc_request_type {
> */
>
> static int storvsc_ringbuffer_size = (256 * PAGE_SIZE);
> +static u32 max_outstanding_req_per_channel;
> +
> +static int storvsc_vcpus_per_sub_channel = 4;
>
> module_param(storvsc_ringbuffer_size, int, S_IRUGO);
> MODULE_PARM_DESC(storvsc_ringbuffer_size, "Ring buffer size (bytes)");
>
> +module_param(storvsc_vcpus_per_sub_channel, int, S_IRUGO);
> +MODULE_PARM_DESC(vcpus_per_sub_channel, "Ratio of VCPUs to subchannels");
> /*
> * Timeout in seconds for all devices managed by this driver.
> */
> @@ -320,7 +325,6 @@ static int storvsc_timeout = 180;
>
> static int msft_blist_flags = BLIST_TRY_VPD_PAGES;
>
> -#define STORVSC_MAX_IO_REQUESTS 200
>
> static void storvsc_on_channel_callback(void *context);
>
> @@ -1376,7 +1380,6 @@ static int storvsc_do_io(struct hv_device *device,
>
> static int storvsc_device_configure(struct scsi_device *sdevice)
> {
> - scsi_change_queue_depth(sdevice, STORVSC_MAX_IO_REQUESTS);
>
> blk_queue_max_segment_size(sdevice->request_queue, PAGE_SIZE);
>
> @@ -1646,7 +1649,6 @@ static struct scsi_host_template scsi_driver = {
> .eh_timed_out = storvsc_eh_timed_out,
> .slave_configure = storvsc_device_configure,
> .cmd_per_lun = 255,
> - .can_queue = STORVSC_MAX_IO_REQUESTS*STORVSC_MAX_TARGETS,
> .this_id = -1,
> /* no use setting to 0 since ll_blk_rw reset it to 1 */
> /* currently 32 */
> @@ -1686,6 +1688,7 @@ static int storvsc_probe(struct hv_device *device,
> const struct hv_vmbus_device_id *dev_id)
> {
> int ret;
> + int num_cpus = num_online_cpus();
> struct Scsi_Host *host;
> struct hv_host_device *host_dev;
> bool dev_is_ide = ((dev_id->driver_data == IDE_GUID) ? true : false);
> @@ -1694,6 +1697,7 @@ static int storvsc_probe(struct hv_device *device,
> int max_luns_per_target;
> int max_targets;
> int max_channels;
> + int max_sub_channels = 0;
>
> /*
> * Based on the windows host we are running on,
> @@ -1719,12 +1723,18 @@ static int storvsc_probe(struct hv_device *device,
> max_luns_per_target = STORVSC_MAX_LUNS_PER_TARGET;
> max_targets = STORVSC_MAX_TARGETS;
> max_channels = STORVSC_MAX_CHANNELS;
> + /*
> + * On Windows8 and above, we support sub-channels for storage.
> + * The number of sub-channels offerred is based on the number of
> + * VCPUs in the guest.
> + */
> + max_sub_channels = (num_cpus / storvsc_vcpus_per_sub_channel);
> break;
> }
>
> - if (dev_id->driver_data == SFC_GUID)
> - scsi_driver.can_queue = (STORVSC_MAX_IO_REQUESTS *
> - STORVSC_FC_MAX_TARGETS);
> + scsi_driver.can_queue = (max_outstanding_req_per_channel *
> + max_sub_channels + 1);
> +
If num_online_cpus() returned 1 - 3, can_queue will be set to 1 I
think. Is that desired?
> host = scsi_host_alloc(&scsi_driver,
> sizeof(struct hv_host_device));
> if (!host)
> @@ -1837,7 +1847,6 @@ static struct hv_driver storvsc_drv = {
>
> static int __init storvsc_drv_init(void)
> {
> - u32 max_outstanding_req_per_channel;
>
> /*
> * Divide the ring buffer data size (which is 1 page less
> @@ -1852,10 +1861,6 @@ static int __init storvsc_drv_init(void)
> vmscsi_size_delta,
> sizeof(u64)));
>
> - if (max_outstanding_req_per_channel <
> - STORVSC_MAX_IO_REQUESTS)
> - return -EINVAL;
> -
> return vmbus_driver_register(&storvsc_drv);
> }
-- vs;
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