On 2021/06/25 2:23, Niklas Cassel wrote:
> From: Niklas Cassel <niklas.cassel@xxxxxxx>
>
> Commit 219c662d3b12 ("zbd: introduce per job maximum open zones limit")
> Introduced a global max open zones limit stored in zbd_info->max_open_zones.
>
> This commit also removed the following check from zbd_open_zone():
>
> if (!td->o.max_open_zones)
> return true;
>
> Before the commit in question, if td->o.max_open_zones == 0, zbd_open_zone()
> would not track the zone as open in the zbd_info->open_zones array.
>
> After the commit in question, zbd_open_zone() would always track the zone
> as open in the zbd_info->open_zones array, regardless if a --max_open_zones
> limit was set or not.
>
> Change the initialization of zbd_info->max_open_zones to yet again allow
> unlimited max open zones. If zbd_info->max_open_zones is unlimited,
> we do not track the open zones in the zbd_info->open zone array.
>
> Not tracking open zones reduces fio overhead for testing the performance of
> zoned block devices that do not have a limit on the maximum number of open
> zones.
>
> Signed-off-by: Niklas Cassel <niklas.cassel@xxxxxxx>
> Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
> ---
> zbd.c | 28 ++++++++++++++++++++++++----
> zbd.h | 3 ++-
> 2 files changed, 26 insertions(+), 5 deletions(-)
>
> diff --git a/zbd.c b/zbd.c
> index f09b0ee6..f19e3d47 100644
> --- a/zbd.c
> +++ b/zbd.c
> @@ -636,8 +636,12 @@ static int zbd_set_max_open_zones(struct thread_data *td, struct fio_file *f)
>
> out:
> /* Ensure that the limit is not larger than FIO's internal limit */
> - zbd->max_open_zones = min_not_zero(zbd->max_open_zones,
> - (uint32_t) ZBD_MAX_OPEN_ZONES);
> + if (zbd->max_open_zones > ZBD_MAX_OPEN_ZONES) {
> + td_verror(td, EINVAL, "'max_open_zones' value is too large");
> + log_err("'max_open_zones' value is larger than %u\n", ZBD_MAX_OPEN_ZONES);
> + return -EINVAL;
> + }
> +
> dprint(FD_ZBD, "%s: using max open zones limit: %"PRIu32"\n",
> f->file_name, zbd->max_open_zones);
>
> @@ -827,8 +831,14 @@ int zbd_setup_files(struct thread_data *td)
> log_err("Different 'max_open_zones' values\n");
> return 1;
> }
> - if (zbd->max_open_zones > ZBD_MAX_OPEN_ZONES) {
> - log_err("'max_open_zones' value is limited by %u\n", ZBD_MAX_OPEN_ZONES);
> +
> + /*
> + * The per job max open zones limit cannot be used without a
> + * global max open zones limit. (As the tracking of open zones
> + * is disabled when there is no global max open zones limit.)
> + */
> + if (td->o.job_max_open_zones && !zbd->max_open_zones) {
> + log_err("'job_max_open_zones' cannot be used without a global open zones limit\n");
> return 1;
> }
>
> @@ -1093,6 +1103,8 @@ static bool is_zone_open(const struct thread_data *td, const struct fio_file *f,
> struct zoned_block_device_info *zbdi = f->zbd_info;
> int i;
>
> + /* This function should never be called when zbdi->max_open_zones == 0 */
> + assert(zbdi->max_open_zones);
> assert(td->o.job_max_open_zones == 0 || td->num_open_zones <= td->o.job_max_open_zones);
> assert(td->o.job_max_open_zones <= zbdi->max_open_zones);
> assert(zbdi->num_open_zones <= zbdi->max_open_zones);
> @@ -1128,6 +1140,14 @@ static bool zbd_open_zone(struct thread_data *td, const struct fio_file *f,
> if (td->o.verify != VERIFY_NONE && zbd_zone_full(f, z, min_bs))
> return false;
>
> + /*
> + * zbdi->max_open_zones == 0 means that there is no limit on the maximum
> + * number of open zones. In this case, do no track open zones in
> + * zbdi->open_zones array.
> + */
> + if (!zbdi->max_open_zones)
> + return true;
> +
> pthread_mutex_lock(&zbdi->mutex);
> if (is_zone_open(td, f, zone_idx)) {
> /*
> diff --git a/zbd.h b/zbd.h
> index 64534393..39dc45e3 100644
> --- a/zbd.h
> +++ b/zbd.h
> @@ -50,7 +50,8 @@ struct fio_zone_info {
> * zoned_block_device_info - zoned block device characteristics
> * @model: Device model.
> * @max_open_zones: global limit on the number of simultaneously opened
> - * sequential write zones.
> + * sequential write zones. A zero value means unlimited open zones,
> + * and that open zones will not be tracked in the open_zones array.
> * @mutex: Protects the modifiable members in this structure (refcount and
> * num_open_zones).
> * @zone_size: size of a single zone in bytes.
>
Looks good.
Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxx>
--
Damien Le Moal
Western Digital Research
