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>
---
v2: Fixed a bug in computing queue depth: Venkatesh Srinivas <venkateshs@xxxxxxxxxx>
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..7f569f9 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));
+
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);
}
--
1.7.4.1
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