[PATCH] zbd: don't lock zones outside working area

[PATCH] zbd: don't lock zones outside working area

[Alexey Dobriyan]

Currently threads tap into each other zones even if their working areas
as defined by [f->file_offset, f->file_offset + f->io_size) don't intersect.

This should remove unnecessary quiescing in iodepth > 1 workloads.

Signed-off-by: Alexey Dobriyan (SK hynix) <adobriyan@gmail.com>
---

 file.h |    3 +++
 zbd.c  |   42 ++++++++++++++++++++++++++++++++----------
 2 files changed, 35 insertions(+), 10 deletions(-)

--- a/file.h
+++ b/file.h
@@ -104,6 +104,9 @@ struct fio_file {
 	 * Zoned block device information. See also zonemode=zbd.
 	 */
 	struct zoned_block_device_info *zbd_info;
+	/* zonemode=zbd working area */
+	uint32_t min_zone;	/* inclusive */
+	uint32_t max_zone;	/* exclusive */
 
 	/*
 	 * Track last end and last start of IO for a given data direction
--- a/zbd.c
+++ b/zbd.c
@@ -156,8 +156,14 @@ static bool zbd_zone_full(const struct fio_file *f, struct fio_zone_info *z,
 		z->wp + required > z->start + f->zbd_info->zone_size;
 }
 
-static void zone_lock(struct thread_data *td, struct fio_zone_info *z)
+static void zone_lock(struct thread_data *td, struct fio_file *f, struct fio_zone_info *z)
 {
+	struct zoned_block_device_info *zbd = f->zbd_info;
+	uint32_t nz = z - zbd->zone_info;
+
+	/* Thread should never lock zones outside its working area. */
+	assert(f->min_zone <= nz && nz < f->max_zone);
+
 	/*
 	 * Lock the io_u target zone. The zone will be unlocked if io_u offset
 	 * is changed or when io_u completes and zbd_put_io() executed.
@@ -289,6 +295,9 @@ static bool zbd_verify_sizes(void)
 					 (unsigned long long) new_end - f->file_offset);
 				f->io_size = new_end - f->file_offset;
 			}
+
+			f->min_zone = zbd_zone_idx(f, f->file_offset);
+			f->max_zone = zbd_zone_idx(f, f->file_offset + f->io_size);
 		}
 	}
 
@@ -332,6 +341,17 @@ static int ilog2(uint64_t i)
 	return log;
 }
 
+static uint32_t clamp_u32(uint32_t x, uint32_t min, uint32_t max)
+{
+	if (x < min) {
+		return min;
+	} else if (x > max) {
+		return max;
+	} else {
+		return x;
+	}
+}
+
 /*
  * Initialize f->zbd_info for devices that are not zoned block devices. This
  * allows to execute a ZBD workload against a non-ZBD device.
@@ -735,7 +755,7 @@ static int zbd_reset_zones(struct thread_data *td, struct fio_file *f,
 
 		if (!zbd_zone_swr(z))
 			continue;
-		zone_lock(td, z);
+		zone_lock(td, f, z);
 		if (all_zones) {
 			unsigned int i;
 
@@ -958,7 +978,7 @@ static struct fio_zone_info *zbd_convert_to_open_zone(struct thread_data *td,
 						      struct io_u *io_u)
 {
 	const uint32_t min_bs = td->o.min_bs[io_u->ddir];
-	const struct fio_file *f = io_u->file;
+	struct fio_file *f = io_u->file;
 	struct fio_zone_info *z;
 	unsigned int open_zone_idx = -1;
 	uint32_t zone_idx, new_zone_idx;
@@ -975,6 +995,7 @@ static struct fio_zone_info *zbd_convert_to_open_zone(struct thread_data *td,
 	} else {
 		zone_idx = zbd_zone_idx(f, io_u->offset);
 	}
+	zone_idx = clamp_u32(zone_idx, f->min_zone, f->max_zone - 1);
 	dprint(FD_ZBD, "%s(%s): starting from zone %d (offset %lld, buflen %lld)\n",
 	       __func__, f->file_name, zone_idx, io_u->offset, io_u->buflen);
 
@@ -989,7 +1010,7 @@ static struct fio_zone_info *zbd_convert_to_open_zone(struct thread_data *td,
 
 		z = &f->zbd_info->zone_info[zone_idx];
 
-		zone_lock(td, z);
+		zone_lock(td, f, z);
 		pthread_mutex_lock(&f->zbd_info->mutex);
 		if (td->o.max_open_zones == 0)
 			goto examine_zone;
@@ -1015,8 +1036,7 @@ static struct fio_zone_info *zbd_convert_to_open_zone(struct thread_data *td,
 			if (tmp_idx >= f->zbd_info->num_open_zones)
 				tmp_idx = 0;
 			tmpz = f->zbd_info->open_zones[tmp_idx];
-
-			if (is_valid_offset(f, f->zbd_info->zone_info[tmpz].start)) {
+			if (f->min_zone <= tmpz && tmpz < f->max_zone) {
 				open_zone_idx = tmp_idx;
 				goto found_candidate_zone;
 			}
@@ -1061,11 +1081,11 @@ examine_zone:
 		z++;
 		if (!is_valid_offset(f, z->start)) {
 			/* Wrap-around. */
-			zone_idx = zbd_zone_idx(f, f->file_offset);
+			zone_idx = f->min_zone;
 			z = &f->zbd_info->zone_info[zone_idx];
 		}
 		assert(is_valid_offset(f, z->start));
-		zone_lock(td, z);
+		zone_lock(td, f, z);
 		if (z->open)
 			continue;
 		if (zbd_open_zone(td, io_u, zone_idx))
@@ -1078,12 +1098,14 @@ examine_zone:
 	pthread_mutex_lock(&f->zbd_info->mutex);
 	for (i = 0; i < f->zbd_info->num_open_zones; i++) {
 		zone_idx = f->zbd_info->open_zones[i];
+		if (!(f->min_zone <= zone_idx && zone_idx < f->max_zone))
+			continue;
 		pthread_mutex_unlock(&f->zbd_info->mutex);
 		pthread_mutex_unlock(&z->mutex);
 
 		z = &f->zbd_info->zone_info[zone_idx];
 
-		zone_lock(td, z);
+		zone_lock(td, f, z);
 		if (z->wp + min_bs <= (z+1)->start)
 			goto out;
 		pthread_mutex_lock(&f->zbd_info->mutex);
@@ -1409,7 +1431,7 @@ enum io_u_action zbd_adjust_block(struct thread_data *td, struct io_u *io_u)
 
 	zbd_check_swd(f);
 
-	zone_lock(td, zb);
+	zone_lock(td, f, zb);
 
 	switch (io_u->ddir) {
 	case DDIR_READ:

Re: [PATCH] zbd: don't lock zones outside working area

[Damien Le Moal]

On 2020/04/24 6:38, Alexey Dobriyan wrote:
> Currently threads tap into each other zones even if their working areas
> as defined by [f->file_offset, f->file_offset + f->io_size) don't intersect.
> 
> This should remove unnecessary quiescing in iodepth > 1 workloads.
> 
> Signed-off-by: Alexey Dobriyan (SK hynix) <adobriyan@gmail.com>
> ---
> 
>  file.h |    3 +++
>  zbd.c  |   42 ++++++++++++++++++++++++++++++++----------
>  2 files changed, 35 insertions(+), 10 deletions(-)
> 
> --- a/file.h
> +++ b/file.h
> @@ -104,6 +104,9 @@ struct fio_file {
>  	 * Zoned block device information. See also zonemode=zbd.
>  	 */
>  	struct zoned_block_device_info *zbd_info;
> +	/* zonemode=zbd working area */
> +	uint32_t min_zone;	/* inclusive */
> +	uint32_t max_zone;	/* exclusive */

For simplicity, what about having both inclusive ?

>  
>  	/*
>  	 * Track last end and last start of IO for a given data direction
> --- a/zbd.c
> +++ b/zbd.c
> @@ -156,8 +156,14 @@ static bool zbd_zone_full(const struct fio_file *f, struct fio_zone_info *z,
>  		z->wp + required > z->start + f->zbd_info->zone_size;
>  }
>  
> -static void zone_lock(struct thread_data *td, struct fio_zone_info *z)
> +static void zone_lock(struct thread_data *td, struct fio_file *f, struct fio_zone_info *z)
>  {
> +	struct zoned_block_device_info *zbd = f->zbd_info;
> +	uint32_t nz = z - zbd->zone_info;
> +
> +	/* Thread should never lock zones outside its working area. */
> +	assert(f->min_zone <= nz && nz < f->max_zone);
> +
>  	/*
>  	 * Lock the io_u target zone. The zone will be unlocked if io_u offset
>  	 * is changed or when io_u completes and zbd_put_io() executed.
> @@ -289,6 +295,9 @@ static bool zbd_verify_sizes(void)
>  					 (unsigned long long) new_end - f->file_offset);
>  				f->io_size = new_end - f->file_offset;
>  			}
> +
> +			f->min_zone = zbd_zone_idx(f, f->file_offset);
> +			f->max_zone = zbd_zone_idx(f, f->file_offset + f->io_size);

"- 1" to make it inclusive ?

>  		}
>  	}
>  
> @@ -332,6 +341,17 @@ static int ilog2(uint64_t i)
>  	return log;
>  }
>  
> +static uint32_t clamp_u32(uint32_t x, uint32_t min, uint32_t max)
> +{
> +	if (x < min) {
> +		return min;
> +	} else if (x > max) {
> +		return max;
> +	} else {
> +		return x;
> +	}
> +}

See below comment.

> +
>  /*
>   * Initialize f->zbd_info for devices that are not zoned block devices. This
>   * allows to execute a ZBD workload against a non-ZBD device.
> @@ -735,7 +755,7 @@ static int zbd_reset_zones(struct thread_data *td, struct fio_file *f,
>  
>  		if (!zbd_zone_swr(z))
>  			continue;
> -		zone_lock(td, z);
> +		zone_lock(td, f, z);
>  		if (all_zones) {
>  			unsigned int i;
>  
> @@ -958,7 +978,7 @@ static struct fio_zone_info *zbd_convert_to_open_zone(struct thread_data *td,
>  						      struct io_u *io_u)
>  {
>  	const uint32_t min_bs = td->o.min_bs[io_u->ddir];
> -	const struct fio_file *f = io_u->file;
> +	struct fio_file *f = io_u->file;
>  	struct fio_zone_info *z;
>  	unsigned int open_zone_idx = -1;
>  	uint32_t zone_idx, new_zone_idx;
> @@ -975,6 +995,7 @@ static struct fio_zone_info *zbd_convert_to_open_zone(struct thread_data *td,
>  	} else {
>  		zone_idx = zbd_zone_idx(f, io_u->offset);
>  	}
> +	zone_idx = clamp_u32(zone_idx, f->min_zone, f->max_zone - 1);

Since this is the only place clamp_u32 is used, I think you could just open code
it here. That plus a comment would make it easier to follow what is going on.
E.g.:

	/*
	 * Limit candidate zones to those contained in the thread working area.
	 */
	if (zone_idx < f->min_zone)
		zone_idx = f->min_zone;
	else if (zone_idx > f->max_zone)
		zone_idx = f->max_zone;


>  	dprint(FD_ZBD, "%s(%s): starting from zone %d (offset %lld, buflen %lld)\n",
>  	       __func__, f->file_name, zone_idx, io_u->offset, io_u->buflen);
>  
> @@ -989,7 +1010,7 @@ static struct fio_zone_info *zbd_convert_to_open_zone(struct thread_data *td,
>  
>  		z = &f->zbd_info->zone_info[zone_idx];
>  
> -		zone_lock(td, z);
> +		zone_lock(td, f, z);
>  		pthread_mutex_lock(&f->zbd_info->mutex);
>  		if (td->o.max_open_zones == 0)
>  			goto examine_zone;
> @@ -1015,8 +1036,7 @@ static struct fio_zone_info *zbd_convert_to_open_zone(struct thread_data *td,
>  			if (tmp_idx >= f->zbd_info->num_open_zones)
>  				tmp_idx = 0;
>  			tmpz = f->zbd_info->open_zones[tmp_idx];
> -
> -			if (is_valid_offset(f, f->zbd_info->zone_info[tmpz].start)) {
> +			if (f->min_zone <= tmpz && tmpz < f->max_zone) {
>  				open_zone_idx = tmp_idx;
>  				goto found_candidate_zone;
>  			}
> @@ -1061,11 +1081,11 @@ examine_zone:
>  		z++;
>  		if (!is_valid_offset(f, z->start)) {
>  			/* Wrap-around. */
> -			zone_idx = zbd_zone_idx(f, f->file_offset);
> +			zone_idx = f->min_zone;
>  			z = &f->zbd_info->zone_info[zone_idx];
>  		}
>  		assert(is_valid_offset(f, z->start));
> -		zone_lock(td, z);
> +		zone_lock(td, f, z);
>  		if (z->open)
>  			continue;
>  		if (zbd_open_zone(td, io_u, zone_idx))
> @@ -1078,12 +1098,14 @@ examine_zone:
>  	pthread_mutex_lock(&f->zbd_info->mutex);
>  	for (i = 0; i < f->zbd_info->num_open_zones; i++) {
>  		zone_idx = f->zbd_info->open_zones[i];
> +		if (!(f->min_zone <= zone_idx && zone_idx < f->max_zone))
> +			continue;

		if (zone_idx < f->min_zone || zone_idx >= f->max_zone))
			continue;

is I think easier to read.

>  		pthread_mutex_unlock(&f->zbd_info->mutex);
>  		pthread_mutex_unlock(&z->mutex);
>  
>  		z = &f->zbd_info->zone_info[zone_idx];
>  
> -		zone_lock(td, z);
> +		zone_lock(td, f, z);
>  		if (z->wp + min_bs <= (z+1)->start)
>  			goto out;
>  		pthread_mutex_lock(&f->zbd_info->mutex);
> @@ -1409,7 +1431,7 @@ enum io_u_action zbd_adjust_block(struct thread_data *td, struct io_u *io_u)
>  
>  	zbd_check_swd(f);
>  
> -	zone_lock(td, zb);
> +	zone_lock(td, f, zb);
>  
>  	switch (io_u->ddir) {
>  	case DDIR_READ:
> 


-- 
Damien Le Moal
Western Digital Research

Re: [PATCH] zbd: don't lock zones outside working area

[Alexey Dobriyan]

On Fri, Apr 24, 2020 at 08:17:25AM +0000, Damien Le Moal wrote:
> On 2020/04/24 6:38, Alexey Dobriyan wrote:
> > Currently threads tap into each other zones even if their working areas
> > as defined by [f->file_offset, f->file_offset + f->io_size) don't intersect.
> > 
> > This should remove unnecessary quiescing in iodepth > 1 workloads.
> > 
> > Signed-off-by: Alexey Dobriyan (SK hynix) <adobriyan@gmail.com>
> > ---
> > 
> >  file.h |    3 +++
> >  zbd.c  |   42 ++++++++++++++++++++++++++++++++----------
> >  2 files changed, 35 insertions(+), 10 deletions(-)
> > 
> > --- a/file.h
> > +++ b/file.h
> > @@ -104,6 +104,9 @@ struct fio_file {
> >  	 * Zoned block device information. See also zonemode=zbd.
> >  	 */
> >  	struct zoned_block_device_info *zbd_info;
> > +	/* zonemode=zbd working area */
> > +	uint32_t min_zone;	/* inclusive */
> > +	uint32_t max_zone;	/* exclusive */
> 
> For simplicity, what about having both inclusive ?

Boundaries are better defined as [inclusive, exclusive),
so that loops and comparisons are shorter

	for (z = min_zone; z < max_zone; z++)

I want to change file's offsets to [f->min_offset, f->max_offset)
because redefining ->io_size is confusing and it will be
inclusive/exclusive as well.

> > --- a/zbd.c
> > +++ b/zbd.c
> > @@ -156,8 +156,14 @@ static bool zbd_zone_full(const struct fio_file *f, struct fio_zone_info *z,
> >  		z->wp + required > z->start + f->zbd_info->zone_size;
> >  }
> >  
> > -static void zone_lock(struct thread_data *td, struct fio_zone_info *z)
> > +static void zone_lock(struct thread_data *td, struct fio_file *f, struct fio_zone_info *z)
> >  {
> > +	struct zoned_block_device_info *zbd = f->zbd_info;
> > +	uint32_t nz = z - zbd->zone_info;
> > +
> > +	/* Thread should never lock zones outside its working area. */
> > +	assert(f->min_zone <= nz && nz < f->max_zone);
> > +
> >  	/*
> >  	 * Lock the io_u target zone. The zone will be unlocked if io_u offset
> >  	 * is changed or when io_u completes and zbd_put_io() executed.
> > @@ -289,6 +295,9 @@ static bool zbd_verify_sizes(void)
> >  					 (unsigned long long) new_end - f->file_offset);
> >  				f->io_size = new_end - f->file_offset;
> >  			}
> > +
> > +			f->min_zone = zbd_zone_idx(f, f->file_offset);
> > +			f->max_zone = zbd_zone_idx(f, f->file_offset + f->io_size);
> 
> "- 1" to make it inclusive ?
> 
> >  		}
> >  	}
> >  
> > @@ -332,6 +341,17 @@ static int ilog2(uint64_t i)
> >  	return log;
> >  }
> >  
> > +static uint32_t clamp_u32(uint32_t x, uint32_t min, uint32_t max)
> > +{
> > +	if (x < min) {
> > +		return min;
> > +	} else if (x > max) {
> > +		return max;
> > +	} else {
> > +		return x;
> > +	}
> > +}
> 
> See below comment.
> 
> > +
> >  /*
> >   * Initialize f->zbd_info for devices that are not zoned block devices. This
> >   * allows to execute a ZBD workload against a non-ZBD device.
> > @@ -735,7 +755,7 @@ static int zbd_reset_zones(struct thread_data *td, struct fio_file *f,
> >  
> >  		if (!zbd_zone_swr(z))
> >  			continue;
> > -		zone_lock(td, z);
> > +		zone_lock(td, f, z);
> >  		if (all_zones) {
> >  			unsigned int i;
> >  
> > @@ -958,7 +978,7 @@ static struct fio_zone_info *zbd_convert_to_open_zone(struct thread_data *td,
> >  						      struct io_u *io_u)
> >  {
> >  	const uint32_t min_bs = td->o.min_bs[io_u->ddir];
> > -	const struct fio_file *f = io_u->file;
> > +	struct fio_file *f = io_u->file;
> >  	struct fio_zone_info *z;
> >  	unsigned int open_zone_idx = -1;
> >  	uint32_t zone_idx, new_zone_idx;
> > @@ -975,6 +995,7 @@ static struct fio_zone_info *zbd_convert_to_open_zone(struct thread_data *td,
> >  	} else {
> >  		zone_idx = zbd_zone_idx(f, io_u->offset);
> >  	}
> > +	zone_idx = clamp_u32(zone_idx, f->min_zone, f->max_zone - 1);
> 
> Since this is the only place clamp_u32 is used, I think you could just open code
> it here. That plus a comment would make it easier to follow what is going on.
> E.g.:
> 
> 	/*
> 	 * Limit candidate zones to those contained in the thread working area.
> 	 */
> 	if (zone_idx < f->min_zone)
> 		zone_idx = f->min_zone;
> 	else if (zone_idx > f->max_zone)
> 		zone_idx = f->max_zone;
> 
> 
> >  	dprint(FD_ZBD, "%s(%s): starting from zone %d (offset %lld, buflen %lld)\n",
> >  	       __func__, f->file_name, zone_idx, io_u->offset, io_u->buflen);
> >  
> > @@ -989,7 +1010,7 @@ static struct fio_zone_info *zbd_convert_to_open_zone(struct thread_data *td,
> >  
> >  		z = &f->zbd_info->zone_info[zone_idx];
> >  
> > -		zone_lock(td, z);
> > +		zone_lock(td, f, z);
> >  		pthread_mutex_lock(&f->zbd_info->mutex);
> >  		if (td->o.max_open_zones == 0)
> >  			goto examine_zone;
> > @@ -1015,8 +1036,7 @@ static struct fio_zone_info *zbd_convert_to_open_zone(struct thread_data *td,
> >  			if (tmp_idx >= f->zbd_info->num_open_zones)
> >  				tmp_idx = 0;
> >  			tmpz = f->zbd_info->open_zones[tmp_idx];
> > -
> > -			if (is_valid_offset(f, f->zbd_info->zone_info[tmpz].start)) {
> > +			if (f->min_zone <= tmpz && tmpz < f->max_zone) {
> >  				open_zone_idx = tmp_idx;
> >  				goto found_candidate_zone;
> >  			}
> > @@ -1061,11 +1081,11 @@ examine_zone:
> >  		z++;
> >  		if (!is_valid_offset(f, z->start)) {
> >  			/* Wrap-around. */
> > -			zone_idx = zbd_zone_idx(f, f->file_offset);
> > +			zone_idx = f->min_zone;
> >  			z = &f->zbd_info->zone_info[zone_idx];
> >  		}
> >  		assert(is_valid_offset(f, z->start));
> > -		zone_lock(td, z);
> > +		zone_lock(td, f, z);
> >  		if (z->open)
> >  			continue;
> >  		if (zbd_open_zone(td, io_u, zone_idx))
> > @@ -1078,12 +1098,14 @@ examine_zone:
> >  	pthread_mutex_lock(&f->zbd_info->mutex);
> >  	for (i = 0; i < f->zbd_info->num_open_zones; i++) {
> >  		zone_idx = f->zbd_info->open_zones[i];
> > +		if (!(f->min_zone <= zone_idx && zone_idx < f->max_zone))
> > +			continue;
> 
> 		if (zone_idx < f->min_zone || zone_idx >= f->max_zone))
> 			continue;
> 
> is I think easier to read.