On 7/26/23 09:57, Bart Van Assche wrote:
> Add a new configfs attribute for disabling zone write locking. The test
> script below reports 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.
>
> #!/bin/bash
>
> for mode in "none 0" "mq-deadline 0" "mq-deadline 1"; do
> set +e
> for d in /sys/kernel/config/nullb/*; do
> [ -d "$d" ] && rmdir "$d"
> done
> modprobe -r null_blk
> set -e
> read -r iosched no_write_locking <<<"$mode"
> modprobe null_blk nr_devices=0
> (
> cd /sys/kernel/config/nullb
> mkdir nullb0
> cd nullb0
> params=(
> completion_nsec=100000
> hw_queue_depth=64
> irqmode=2 # NULL_IRQ_TIMER
> max_sectors=$((4096/512))
> memory_backed=1
> no_zone_write_lock="${no_write_locking}"
> size=1
> submit_queues=1
> zone_size=1
> zoned=1
> power=1
> )
> for p in "${params[@]}"; do
> echo "${p//*=}" > "${p//=*}"
> done
> )
> udevadm settle
> dev=/dev/nullb0
> [ -b "${dev}" ]
> params=(
> --direct=1
> --filename="${dev}"
> --iodepth=64
> --iodepth_batch=16
> --ioengine=io_uring
> --ioscheduler="${iosched}"
> --gtod_reduce=1
> --hipri=0
> --name=nullb0
> --runtime=30
> --rw=write
> --time_based=1
> --zonemode=zbd
> )
> fio "${params[@]}"
> done
>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
> 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);
This patch look OK, but there is no patch introducing
QUEUE_FLAG_NO_ZONE_WRITE_LOCK... Patch 1 only introduced REQ_NO_ZONE_WRITE_LOCK.
So the series as is will not compile.
> +
> 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",
--
Damien Le Moal
Western Digital Research
