On 2019-3-6 14:27, Damien Le Moal wrote:
> For zoned block devices, an array of zone types for each device is
> allocated and initialized in order to determine if a section is stored
> on a sequential zone (zone reset needed) or a conventional zone (no
> zone reset needed and regular discard applies). Considering this usage,
> the zone types stored in memory can be replaced with a bitmap to
> indicate an equivalent information, that is, if a zone is sequential or
> not. This reduces the memory usage for each zoned device by roughly 8:
> on a 14TB disk with zones of 256 MB, the zone type array consumes
> 13x4KB pages while the bitmap uses only 2x4KB pages.
>
> This patch changes the f2fs_dev_info structure blkz_type field to the
> bitmap blkz_seq. Access to this bitmap is done using the helper
> function f2fs_blkz_is_seq(), which is a rewrite of the function
> get_blkz_type().
>
> Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxx>
> ---
> Changes from v1:
> * Use kvfree() instead of kfree() to free the zone bitmap
>
> fs/f2fs/f2fs.h | 13 +++++++------
> fs/f2fs/segment.c | 23 +++++++----------------
> fs/f2fs/super.c | 13 ++++++++-----
> 3 files changed, 22 insertions(+), 27 deletions(-)
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 12fabd6735dd..d7b2de930352 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1067,8 +1067,8 @@ struct f2fs_dev_info {
> block_t start_blk;
> block_t end_blk;
> #ifdef CONFIG_BLK_DEV_ZONED
> - unsigned int nr_blkz; /* Total number of zones */
> - u8 *blkz_type; /* Array of zones type */
> + unsigned int nr_blkz; /* Total number of zones */
> + unsigned long *blkz_seq; /* Bitmap indicating sequential zones */
> #endif
> };
>
> @@ -3508,16 +3508,17 @@ F2FS_FEATURE_FUNCS(lost_found, LOST_FOUND);
> F2FS_FEATURE_FUNCS(sb_chksum, SB_CHKSUM);
>
> #ifdef CONFIG_BLK_DEV_ZONED
> -static inline int get_blkz_type(struct f2fs_sb_info *sbi,
> - struct block_device *bdev, block_t blkaddr)
> +static inline bool f2fs_blkz_is_seq(struct f2fs_sb_info *sbi,
> + struct block_device *bdev, block_t blkaddr)
> {
> unsigned int zno = blkaddr >> sbi->log_blocks_per_blkz;
> int i;
>
> for (i = 0; i < sbi->s_ndevs; i++)
> if (FDEV(i).bdev == bdev)
> - return FDEV(i).blkz_type[zno];
> - return -EINVAL;
> + return test_bit(zno, FDEV(i).blkz_seq);
> + WARN_ON_ONCE(1);
> + return false;
How about just handling this case as previous instead of treating device as
conventional zone?
Thanks,
> }
> #endif
>
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 9b79056d705d..65941070776c 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1703,19 +1703,8 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
> blkstart -= FDEV(devi).start_blk;
> }
>
> - /*
> - * We need to know the type of the zone: for conventional zones,
> - * use regular discard if the drive supports it. For sequential
> - * zones, reset the zone write pointer.
> - */
> - switch (get_blkz_type(sbi, bdev, blkstart)) {
> -
> - case BLK_ZONE_TYPE_CONVENTIONAL:
> - if (!blk_queue_discard(bdev_get_queue(bdev)))
> - return 0;
> - return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
> - case BLK_ZONE_TYPE_SEQWRITE_REQ:
> - case BLK_ZONE_TYPE_SEQWRITE_PREF:
> + /* For sequential zones, reset the zone write pointer */
> + if (f2fs_blkz_is_seq(sbi, bdev, blkstart)) {
> sector = SECTOR_FROM_BLOCK(blkstart);
> nr_sects = SECTOR_FROM_BLOCK(blklen);
>
> @@ -1730,10 +1719,12 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
> trace_f2fs_issue_reset_zone(bdev, blkstart);
> return blkdev_reset_zones(bdev, sector,
> nr_sects, GFP_NOFS);
> - default:
> - /* Unknown zone type: broken device ? */
> - return -EIO;
> }
> +
> + /* For conventional zones, use regular discard if supported */
> + if (!blk_queue_discard(bdev_get_queue(bdev)))
> + return 0;
> + return __queue_discard_cmd(sbi, bdev, lblkstart, blklen);
> }
> #endif
>
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index c46a1d4318d4..91d7429be554 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -1017,7 +1017,7 @@ static void destroy_device_list(struct f2fs_sb_info *sbi)
> for (i = 0; i < sbi->s_ndevs; i++) {
> blkdev_put(FDEV(i).bdev, FMODE_EXCL);
> #ifdef CONFIG_BLK_DEV_ZONED
> - kvfree(FDEV(i).blkz_type);
> + kvfree(FDEV(i).blkz_seq);
> #endif
> }
> kvfree(sbi->devs);
> @@ -2765,9 +2765,11 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
> if (nr_sectors & (bdev_zone_sectors(bdev) - 1))
> FDEV(devi).nr_blkz++;
>
> - FDEV(devi).blkz_type = f2fs_kmalloc(sbi, FDEV(devi).nr_blkz,
> - GFP_KERNEL);
> - if (!FDEV(devi).blkz_type)
> + FDEV(devi).blkz_seq = f2fs_kzalloc(sbi,
> + BITS_TO_LONGS(FDEV(devi).nr_blkz)
> + * sizeof(unsigned long),
> + GFP_KERNEL);
> + if (!FDEV(devi).blkz_seq)
> return -ENOMEM;
>
> #define F2FS_REPORT_NR_ZONES 4096
> @@ -2794,7 +2796,8 @@ static int init_blkz_info(struct f2fs_sb_info *sbi, int devi)
> }
>
> for (i = 0; i < nr_zones; i++) {
> - FDEV(devi).blkz_type[n] = zones[i].type;
> + if (zones[i].type != BLK_ZONE_TYPE_CONVENTIONAL)
> + set_bit(n, FDEV(devi).blkz_seq);
> sector += zones[i].len;
> n++;
> }
>
