Re: [f2fs-dev] [PATCH] f2fs:Add write priority option based on zone UFS

[Chao Yu <chao@kernel.org>]

On 2024/7/2 14:29, Liao Yuanhong wrote:
> Currently, we are using a mix of traditional UFS and zone UFS to support
> some functionalities that cannot be achieved on zone UFS alone. However,
> there are some issues with this approach. There exists a significant
> performance difference between traditional UFS and zone UFS. Under normal
> usage, we prioritize writes to zone UFS. However, in critical conditions
> (such as when the entire UFS is almost full), we cannot determine whether
> data will be written to traditional UFS or zone UFS. This can lead to
> significant performance fluctuations, which is not conducive to
> development and testing. To address this, we have added an option
> zlu_io_enable under sys with the following three modes:
> 1) zlu_io_enable == 0:Normal mode, prioritize writing to zone UFS;
> 2) zlu_io_enable == 1:Zone UFS only mode, only allow writing to zone UFS;
> 3) zlu_io_enable == 2:Traditional UFS priority mode, prioritize writing to
> traditional UFS.

Use blkzone_alloc_policy instead of zlu_io_enable? Not sure.

Should update manual of f2fs sysfs entry.

> 
> Signed-off-by: Liao Yuanhong <liaoyuanhong@vivo.com>
> Signed-off-by: Wu Bo <bo.wu@vivo.com>
> ---
>   fs/f2fs/f2fs.h    |  5 +++++
>   fs/f2fs/segment.c | 23 ++++++++++++++++++++++-
>   fs/f2fs/sysfs.c   | 13 +++++++++++++
>   3 files changed, 40 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index f7ee6c5e371e..7ba782bd15b2 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1781,6 +1781,11 @@ struct f2fs_sb_info {
>   	u64 committed_atomic_block;
>   	u64 revoked_atomic_block;
>   
> +#ifdef CONFIG_BLK_DEV_ZONED
> +	/* For adjust the priority writing position of data in zone UFS */
> +	unsigned int zlu_io_enable;		/* data write mode */
> +#endif

#ifdef CONFIG_BLK_DEV_ZONED
	unsigned int blocks_per_blkz;		/* F2FS blocks per zone */
	unsigned int max_open_zones;		/* max open zone resources of the zoned device */
	/* For adjust the priority writing position of data in zone UFS */
	unsigned int zlu_io_enable;		/* data write mode */
#endif

> +
>   #ifdef CONFIG_F2FS_FS_COMPRESSION
>   	struct kmem_cache *page_array_slab;	/* page array entry */
>   	unsigned int page_array_slab_size;	/* default page array slab size */
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 4db1add43e36..327457c28700 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -2686,17 +2686,38 @@ static int get_new_segment(struct f2fs_sb_info *sbi,
>   			goto got_it;
>   	}
>   
> +#ifdef CONFIG_BLK_DEV_ZONED
>   	/*
>   	 * If we format f2fs on zoned storage, let's try to get pinned sections
>   	 * from beginning of the storage, which should be a conventional one.
>   	 */
>   	if (f2fs_sb_has_blkzoned(sbi)) {
> -		segno = pinning ? 0 : max(first_zoned_segno(sbi), *newseg);
> +		if (sbi->zlu_io_enable == 2)		/* Prioritize writing to traditional UFS */

Please use a macro instead of magic number.

> +			segno = 0;
> +		else
> +			segno = pinning ? 0 : max(first_zoned_segno(sbi), *newseg);
>   		hint = GET_SEC_FROM_SEG(sbi, segno);
>   	}
> +#endif
>   
>   find_other_zone:
>   	secno = find_next_zero_bit(free_i->free_secmap, MAIN_SECS(sbi), hint);
> +
> +#ifdef CONFIG_BLK_DEV_ZONED
> +	if (secno >= MAIN_SECS(sbi) && f2fs_sb_has_blkzoned(sbi)) {
> +		if (sbi->zlu_io_enable == 1) {		/* Write only to zone UFS */

Ditto.

And we'd better initialize it w/ default policy in somewhere.

> +			hint = GET_SEC_FROM_SEG(sbi, first_zoned_segno(sbi));
> +			secno = find_next_zero_bit(free_i->free_secmap, MAIN_SECS(sbi), hint);
> +		} else
> +			secno = find_first_zero_bit(free_i->free_secmap,
> +								MAIN_SECS(sbi));
> +		if (secno >= MAIN_SECS(sbi)) {
> +			ret = -ENOSPC;
> +			goto out_unlock;
> +		}
> +	}
> +#endif
> +
>   	if (secno >= MAIN_SECS(sbi)) {
>   		secno = find_first_zero_bit(free_i->free_secmap,
>   							MAIN_SECS(sbi));
> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> index fee7ee45ceaa..bc9e5e8bb749 100644
> --- a/fs/f2fs/sysfs.c
> +++ b/fs/f2fs/sysfs.c
> @@ -627,6 +627,13 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
>   	}
>   #endif
>   
> +#ifdef CONFIG_BLK_DEV_ZONED
> +	if (!strcmp(a->attr.name, "zlu_io_enable")) {

Should check validation of new value?

> +		sbi->zlu_io_enable = t;
> +		return count;
> +	}
> +#endif
> +
>   #ifdef CONFIG_F2FS_FS_COMPRESSION
>   	if (!strcmp(a->attr.name, "compr_written_block") ||
>   		!strcmp(a->attr.name, "compr_saved_block")) {
> @@ -1006,6 +1013,9 @@ F2FS_SBI_GENERAL_RW_ATTR(dir_level);
>   F2FS_SBI_GENERAL_RW_ATTR(iostat_enable);
>   F2FS_SBI_GENERAL_RW_ATTR(iostat_period_ms);
>   #endif
> +#ifdef CONFIG_BLK_DEV_ZONED
> +F2FS_SBI_GENERAL_RW_ATTR(zlu_io_enable);

#ifdef CONFIG_BLK_DEV_ZONED
F2FS_SBI_GENERAL_RO_ATTR(unusable_blocks_per_sec);
F2FS_SBI_GENERAL_RW_ATTR(zlu_io_enable);
#endif

Thanks,

> +#endif
>   F2FS_SBI_GENERAL_RW_ATTR(readdir_ra);
>   F2FS_SBI_GENERAL_RW_ATTR(max_io_bytes);
>   F2FS_SBI_GENERAL_RW_ATTR(data_io_flag);
> @@ -1153,6 +1163,9 @@ static struct attribute *f2fs_attrs[] = {
>   #ifdef CONFIG_F2FS_IOSTAT
>   	ATTR_LIST(iostat_enable),
>   	ATTR_LIST(iostat_period_ms),
> +#endif
> +#ifdef CONFIG_BLK_DEV_ZONED
> +	ATTR_LIST(zlu_io_enable),
>   #endif
>   	ATTR_LIST(readdir_ra),
>   	ATTR_LIST(max_io_bytes),


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