Re: [PATCH v2 2/8] zbd: remove CHECK_SWD feature

[Niklas Cassel <Niklas.Cassel@wdc.com>]

On Tue, Feb 07, 2023 at 03:37:33PM +0900, Shin'ichiro Kawasaki wrote:
> The 'sectors with data' accounting had been used for CHECK_SWD debug
> feature. It compared expected written data size and actually written
> data size for zonemode=zbd. However, this feature has been disabled for
> a while and not actively used. Also, the sector with data accounting has
> two issues. The first issue is wrong accounting for multiple jobs with
> different write ranges. The second issue is job start up failure due to
> zone lock contention.
> 
> Avoid using the accounting by removing the CHECK_SWD feature and related
> code. Also rename the function zbd_process_swd() to zbd_set_swd() to
> clarify that it no longer works for CHECK_SWD.
> 
> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
> ---
>  zbd.c | 38 +++-----------------------------------
>  1 file changed, 3 insertions(+), 35 deletions(-)
> 
> diff --git a/zbd.c b/zbd.c
> index f5e76c40..b6cf2a93 100644
> --- a/zbd.c
> +++ b/zbd.c
> @@ -1190,14 +1190,7 @@ static bool zbd_dec_and_reset_write_cnt(const struct thread_data *td,
>  	return write_cnt == 0;
>  }
>  
> -enum swd_action {
> -	CHECK_SWD,
> -	SET_SWD,
> -};
> -
> -/* Calculate the number of sectors with data (swd) and perform action 'a' */
> -static uint64_t zbd_process_swd(struct thread_data *td,
> -				const struct fio_file *f, enum swd_action a)
> +static uint64_t zbd_set_swd(struct thread_data *td, const struct fio_file *f)
>  {
>  	struct fio_zone_info *zb, *ze, *z;
>  	uint64_t wp_swd = 0;
> @@ -1212,14 +1205,7 @@ static uint64_t zbd_process_swd(struct thread_data *td,
>  	}
>  
>  	pthread_mutex_lock(&f->zbd_info->mutex);
> -	switch (a) {
> -	case CHECK_SWD:
> -		assert(f->zbd_info->wp_sectors_with_data == wp_swd);
> -		break;
> -	case SET_SWD:
> -		f->zbd_info->wp_sectors_with_data = wp_swd;
> -		break;
> -	}
> +	f->zbd_info->wp_sectors_with_data = wp_swd;
>  	pthread_mutex_unlock(&f->zbd_info->mutex);
>  
>  	for (z = zb; z < ze; z++)
> @@ -1229,21 +1215,6 @@ static uint64_t zbd_process_swd(struct thread_data *td,
>  	return wp_swd;
>  }
>  
> -/*
> - * The swd check is useful for debugging but takes too much time to leave
> - * it enabled all the time. Hence it is disabled by default.
> - */
> -static const bool enable_check_swd = false;
> -
> -/* Check whether the values of zbd_info.*sectors_with_data are correct. */
> -static void zbd_check_swd(struct thread_data *td, const struct fio_file *f)
> -{
> -	if (!enable_check_swd)
> -		return;
> -
> -	zbd_process_swd(td, f, CHECK_SWD);
> -}
> -
>  void zbd_file_reset(struct thread_data *td, struct fio_file *f)
>  {
>  	struct fio_zone_info *zb, *ze;
> @@ -1255,7 +1226,7 @@ void zbd_file_reset(struct thread_data *td, struct fio_file *f)
>  
>  	zb = zbd_get_zone(f, f->min_zone);
>  	ze = zbd_get_zone(f, f->max_zone);
> -	swd = zbd_process_swd(td, f, SET_SWD);
> +	swd = zbd_set_swd(td, f);
>  
>  	dprint(FD_ZBD, "%s(%s): swd = %" PRIu64 "\n",
>  	       __func__, f->file_name, swd);
> @@ -1677,7 +1648,6 @@ static void zbd_put_io(struct thread_data *td, const struct io_u *io_u)
>  	zbd_end_zone_io(td, io_u, z);
>  
>  	zone_unlock(z);
> -	zbd_check_swd(td, f);
>  }
>  
>  /*
> @@ -1866,8 +1836,6 @@ enum io_u_action zbd_adjust_block(struct thread_data *td, struct io_u *io_u)
>  	    io_u->ddir == DDIR_READ && td->o.read_beyond_wp)
>  		return io_u_accept;
>  
> -	zbd_check_swd(td, f);
> -
>  	zone_lock(td, f, zb);
>  
>  	switch (io_u->ddir) {
> -- 
> 2.38.1
> 

Reviewed-by: Niklas Cassel <niklas.cassel@wdc.com>