diff mbox series

[v4,05/13] btrfs: zoned: Cache superblock location in btrfs_zoned_device_info

Message ID 20220516165416.171196-6-p.raghav@samsung.com (mailing list archive)
State New, archived
Headers show
Series [v4,01/13] block: make blkdev_nr_zones and blk_queue_zone_no generic for npo2 zsze | expand

Commit Message

Pankaj Raghav May 16, 2022, 4:54 p.m. UTC 
Instead of calculating the superblock location every time, cache the
superblock zone location in btrfs_zoned_device_info struct and use it to
locate the zone index.

The functions such as btrfs_sb_log_location_bdev() and
btrfs_reset_sb_log_zones() which work directly on block_device shall
continue to use the sb_zone_number because btrfs_zoned_device_info
struct might not have been initialized at that point.

This patch will enable non power-of-2 zoned devices to not perform
division to lookup superblock and its mirror location.

Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
---
 fs/btrfs/zoned.c | 13 +++++++++----
 fs/btrfs/zoned.h |  1 +
 2 files changed, 10 insertions(+), 4 deletions(-)

Comments

David Sterba May 16, 2022, 9:58 p.m. UTC | #1 
On Mon, May 16, 2022 at 06:54:08PM +0200, Pankaj Raghav wrote:
> Instead of calculating the superblock location every time, cache the
> superblock zone location in btrfs_zoned_device_info struct and use it to
> locate the zone index.
> 
> The functions such as btrfs_sb_log_location_bdev() and
> btrfs_reset_sb_log_zones() which work directly on block_device shall
> continue to use the sb_zone_number because btrfs_zoned_device_info
> struct might not have been initialized at that point.
> 
> This patch will enable non power-of-2 zoned devices to not perform
> division to lookup superblock and its mirror location.
> 
> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
> Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
> ---
>  fs/btrfs/zoned.c | 13 +++++++++----
>  fs/btrfs/zoned.h |  1 +
>  2 files changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
> index 06f22c021..e8c7cebb2 100644
> --- a/fs/btrfs/zoned.c
> +++ b/fs/btrfs/zoned.c
> @@ -511,6 +511,11 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device, bool populate_cache)
>  			   max_active_zones - nactive);
>  	}
>  
> +	/* Cache the sb zone number */
> +	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; ++i) {
> +		zone_info->sb_zone_location[i] =
> +			sb_zone_number(zone_info->zone_size_shift, i);
> +	}

I don't think we need to cache the value right now, it's not in any hot
path and call to bdev_zone_no is relatively cheap (only dereferencing a
few pointers, all in-memory values).
Pankaj Raghav May 17, 2022, 7:55 a.m. UTC | #2 
On 2022-05-16 23:58, David Sterba wrote:
>> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
>> Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
>> ---
>>  fs/btrfs/zoned.c | 13 +++++++++----
>>  fs/btrfs/zoned.h |  1 +
>>  2 files changed, 10 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
>> index 06f22c021..e8c7cebb2 100644
>> --- a/fs/btrfs/zoned.c
>> +++ b/fs/btrfs/zoned.c
>> @@ -511,6 +511,11 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device, bool populate_cache)
>>  			   max_active_zones - nactive);
>>  	}
>>  
>> +	/* Cache the sb zone number */
>> +	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; ++i) {
>> +		zone_info->sb_zone_location[i] =
>> +			sb_zone_number(zone_info->zone_size_shift, i);
>> +	}
> 
> I don't think we need to cache the value right now, it's not in any hot
> path and call to bdev_zone_no is relatively cheap (only dereferencing a
> few pointers, all in-memory values).
Ok. I will fix it up in the next revision! Thanks.
diff mbox series

Patch

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 06f22c021..e8c7cebb2 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -511,6 +511,11 @@  int btrfs_get_dev_zone_info(struct btrfs_device *device, bool populate_cache)
 			   max_active_zones - nactive);
 	}
 
+	/* Cache the sb zone number */
+	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; ++i) {
+		zone_info->sb_zone_location[i] =
+			sb_zone_number(zone_info->zone_size_shift, i);
+	}
 	/* Validate superblock log */
 	nr_zones = BTRFS_NR_SB_LOG_ZONES;
 	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
@@ -518,7 +523,7 @@  int btrfs_get_dev_zone_info(struct btrfs_device *device, bool populate_cache)
 		u64 sb_wp;
 		int sb_pos = BTRFS_NR_SB_LOG_ZONES * i;
 
-		sb_zone = sb_zone_number(zone_info->zone_size_shift, i);
+		sb_zone = zone_info->sb_zone_location[i];
 		if (sb_zone + 1 >= zone_info->nr_zones)
 			continue;
 
@@ -866,7 +871,7 @@  int btrfs_sb_log_location(struct btrfs_device *device, int mirror, int rw,
 		return 0;
 	}
 
-	zone_num = sb_zone_number(zinfo->zone_size_shift, mirror);
+	zone_num = zinfo->sb_zone_location[mirror];
 	if (zone_num + 1 >= zinfo->nr_zones)
 		return -ENOENT;
 
@@ -883,7 +888,7 @@  static inline bool is_sb_log_zone(struct btrfs_zoned_device_info *zinfo,
 	if (!zinfo)
 		return false;
 
-	zone_num = sb_zone_number(zinfo->zone_size_shift, mirror);
+	zone_num = zinfo->sb_zone_location[mirror];
 	if (zone_num + 1 >= zinfo->nr_zones)
 		return false;
 
@@ -1011,7 +1016,7 @@  u64 btrfs_find_allocatable_zones(struct btrfs_device *device, u64 hole_start,
 			u32 sb_zone;
 			u64 sb_pos;
 
-			sb_zone = sb_zone_number(shift, i);
+			sb_zone = zinfo->sb_zone_location[i];
 			if (!(end <= sb_zone ||
 			      sb_zone + BTRFS_NR_SB_LOG_ZONES <= begin)) {
 				have_sb = true;
diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h
index 10f31d1c8..694ab6d1e 100644
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -27,6 +27,7 @@  struct btrfs_zoned_device_info {
 	unsigned long *active_zones;
 	struct blk_zone *zone_cache;
 	struct blk_zone sb_zones[2 * BTRFS_SUPER_MIRROR_MAX];
+	u32 sb_zone_location[BTRFS_SUPER_MIRROR_MAX];
 };
 
 #ifdef CONFIG_BLK_DEV_ZONED