Re: [PATCH 8/8] loop: allow user to set the queue depth

On Sep 21, 2021, at 4:21 AM, Chaitanya Kulkarni [off-list ref] wrote:

From: Chaitanya Kulkarni <kch@nvidia.com>

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 <kch@nvidia.com>
---
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 6478d3b0dd2a..aeba72b5dd2d 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c

@@ -2096,6 +2096,9 @@ 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);

@@ -2328,7 +2331,7 @@ static int loop_add(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 |
-- 
2.29.0