On Thu, Jul 27, 2023 at 2:22 AM Bart Van Assche <bvanassche@xxxxxxx> wrote:
>
> Add a new configfs attribute for disabling zone write locking. Tests
> show a performance of 250 K IOPS with no I/O scheduler, 6 K IOPS with
> mq-deadline and write locking enabled and 123 K IOPS with mq-deadline
> and write locking disabled. This shows that disabling write locking
> results in about 20 times more IOPS for this particular test case.
>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Damien Le Moal <dlemoal@xxxxxxxxxx>
> Cc: Ming Lei <ming.lei@xxxxxxxxxx>
> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
> ---
> drivers/block/null_blk/main.c | 2 ++
> drivers/block/null_blk/null_blk.h | 1 +
> drivers/block/null_blk/zoned.c | 3 +++
> 3 files changed, 6 insertions(+)
>
> diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
> index 864013019d6b..5c0578137f51 100644
> --- a/drivers/block/null_blk/main.c
> +++ b/drivers/block/null_blk/main.c
> @@ -424,6 +424,7 @@ NULLB_DEVICE_ATTR(zone_capacity, ulong, NULL);
> NULLB_DEVICE_ATTR(zone_nr_conv, uint, NULL);
> NULLB_DEVICE_ATTR(zone_max_open, uint, NULL);
> NULLB_DEVICE_ATTR(zone_max_active, uint, NULL);
> +NULLB_DEVICE_ATTR(no_zone_write_lock, bool, NULL);
> NULLB_DEVICE_ATTR(virt_boundary, bool, NULL);
> NULLB_DEVICE_ATTR(no_sched, bool, NULL);
> NULLB_DEVICE_ATTR(shared_tag_bitmap, bool, NULL);
> @@ -569,6 +570,7 @@ static struct configfs_attribute *nullb_device_attrs[] = {
> &nullb_device_attr_zone_max_active,
> &nullb_device_attr_zone_readonly,
> &nullb_device_attr_zone_offline,
> + &nullb_device_attr_no_zone_write_lock,
> &nullb_device_attr_virt_boundary,
> &nullb_device_attr_no_sched,
> &nullb_device_attr_shared_tag_bitmap,
> diff --git a/drivers/block/null_blk/null_blk.h b/drivers/block/null_blk/null_blk.h
> index 929f659dd255..b521096bcc3f 100644
> --- a/drivers/block/null_blk/null_blk.h
> +++ b/drivers/block/null_blk/null_blk.h
> @@ -117,6 +117,7 @@ struct nullb_device {
> bool memory_backed; /* if data is stored in memory */
> bool discard; /* if support discard */
> bool zoned; /* if device is zoned */
> + bool no_zone_write_lock;
> bool virt_boundary; /* virtual boundary on/off for the device */
> bool no_sched; /* no IO scheduler for the device */
> bool shared_tag_bitmap; /* use hostwide shared tags */
> diff --git a/drivers/block/null_blk/zoned.c b/drivers/block/null_blk/zoned.c
> index 55c5b48bc276..31c8364a63e9 100644
> --- a/drivers/block/null_blk/zoned.c
> +++ b/drivers/block/null_blk/zoned.c
> @@ -96,6 +96,9 @@ int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q)
>
> spin_lock_init(&dev->zone_res_lock);
>
> + if (dev->no_zone_write_lock)
> + blk_queue_flag_set(QUEUE_FLAG_NO_ZONE_WRITE_LOCK, q);
> +
> if (dev->zone_nr_conv >= dev->nr_zones) {
> dev->zone_nr_conv = dev->nr_zones - 1;
> pr_info("changed the number of conventional zones to %u",
Reviewed-by: Nitesh Shetty <nj.shetty@xxxxxxxxxxx>
