On Sun, Sep 05, 2021 at 11:15:16AM -0400, Michael S. Tsirkin wrote:

On Sun, Sep 05, 2021 at 01:20:24PM +0300, Leon Romanovsky wrote:

quoted

On Sun, Sep 05, 2021 at 01:49:46AM -0700, Chaitanya Kulkarni wrote:

quoted

On 9/5/2021 12:46 AM, Leon Romanovsky wrote:

quoted

quoted

+static unsigned int num_request_queues;
+module_param_cb(num_request_queues, &queue_count_ops, &num_request_queues,
+		0644);
+MODULE_PARM_DESC(num_request_queues,
+		 "Number of request queues to use for blk device. Should > 0");
+

Won't it limit all virtio block devices to the same limit?

It is very common to see multiple virtio-blk devices on the same system
and they probably need different limits.

Thanks

Without looking into the code, that can be done adding a configfs

interface and overriding a global value (module param) when it is set from

configfs.

So why should we do double work instead of providing one working
interface from the beginning?

Thanks

quoted

The main way to do it is really from the hypervisor. This one
is a pretty blunt instrument, Max here says it's useful to reduce
memory usage of the driver. If that's the usecase then a global limit
seems sufficient.

How memory will you reduce? It is worth to write it in the commit message.

Thanks

-- 
MST