On 6/22/21 4:19 PM, Chaitanya Kulkarni wrote:
> Instead of hardcoding queue depth allow user to set the hw queue depth
> using module parameter. Set default value to 128 to retain the existing
> behavior.
>
> Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@xxxxxxx>
> ---
> drivers/block/loop.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index 6fc3cfa87598..c0d54ffd6ef3 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -1942,6 +1942,9 @@ module_param(max_loop, int, 0444);
> MODULE_PARM_DESC(max_loop, "Maximum number of loop devices");
> module_param(max_part, int, 0444);
> MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device");
> +static int hw_queue_depth = 128;
> +module_param_named(hw_queue_depth, hw_queue_depth, int, 0444);
> +MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: 128");
> MODULE_LICENSE("GPL");
> MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR);
>
> @@ -2094,7 +2097,7 @@ static int loop_add(struct loop_device **l, int i)
> err = -ENOMEM;
> lo->tag_set.ops = &loop_mq_ops;
> lo->tag_set.nr_hw_queues = 1;
> - lo->tag_set.queue_depth = 128;
> + lo->tag_set.queue_depth = hw_queue_depth;
> lo->tag_set.numa_node = NUMA_NO_NODE;
> lo->tag_set.cmd_size = sizeof(struct loop_cmd);
> lo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_STACKING;
Is there any use case for which the performance improves by using
another queue depth than the default?
Thanks,
Bart.
