Re: [PATCH 2/2] f2fs: introduce gc_mode sysfs node

[Chao Yu]

Minor comments below.

On 2022/10/25 11:32, Yangtao Li wrote:
> gc_mode sysfs node can show the current gc_mode as a string.
> Introducing it increases readability.
Introducing it to increase readability.

> Signed-off-by: Yangtao Li <frank.li@xxxxxxxx>
> ---
>   Documentation/ABI/testing/sysfs-fs-f2fs |  6 ++++++
>   fs/f2fs/f2fs.h                          |  1 +
>   fs/f2fs/sysfs.c                         | 18 ++++++++++++++++++
>   3 files changed, 25 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
> index 483639fb727b..6466f3b1f0a9 100644
> --- a/Documentation/ABI/testing/sysfs-fs-f2fs
> +++ b/Documentation/ABI/testing/sysfs-fs-f2fs
> @@ -634,3 +634,9 @@ Date:		July 2022
>   Contact:	"Daeho Jeong" <daehojeong@xxxxxxxxxx>
>   Description:	Show the accumulated total revoked atomic write block count after boot.
>   		If you write "0" here, you can initialize to "0".
> +
> +What:		/sys/fs/f2fs/<disk>/gc_mode
> +Date:		October 2022
> +Contact:	"Yangtao Li" <frank.li@xxxxxxxx>
> +Description:	Show the current gc_mode as a string.
> +		This is a read-only entry.
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index e6355a5683b7..80f23e44a442 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1318,6 +1318,7 @@ enum {
>   	MAX_TIME,
>   };
>   
> +/* Note that you need to keep synchronization with this gc_mode_names array */

Good point.

/* Modification on enum should be synchronized with gc_mode_names array */

>   enum {
>   	GC_NORMAL,
>   	GC_IDLE_CB,
> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> index 49898a7243ba..058857d8b3b9 100644
> --- a/fs/f2fs/sysfs.c
> +++ b/fs/f2fs/sysfs.c
> @@ -41,6 +41,16 @@ enum {
>   	ATGC_INFO,	/* struct atgc_management */
>   };
>   
> +static const char *gc_mode_names[MAX_GC_MODE] = {
> +		"GC_NORMAL",
> +		"GC_IDLE_CB",
> +		"GC_IDLE_GREEDY",
> +		"GC_IDLE_AT",
> +		"GC_URGENT_HIGH",
> +		"GC_URGENT_LOW",
> +		"GC_URGENT_MID"
> +};
> +
>   struct f2fs_attr {
>   	struct attribute attr;
>   	ssize_t (*show)(struct f2fs_attr *, struct f2fs_sb_info *, char *);
> @@ -133,6 +143,12 @@ static ssize_t pending_discard_show(struct f2fs_attr *a,
>   				&SM_I(sbi)->dcc_info->discard_cmd_cnt));
>   }
>   
> +static ssize_t gc_mode_show(struct f2fs_attr *a,
> +		struct f2fs_sb_info *sbi, char *buf)
> +{
> +	return sprintf(buf, "%s\n", gc_mode_names[sbi->gc_mode]);
> +}
> +
>   static ssize_t features_show(struct f2fs_attr *a,
>   		struct f2fs_sb_info *sbi, char *buf)
>   {
> @@ -823,6 +839,7 @@ F2FS_GENERAL_RO_ATTR(encoding);
>   F2FS_GENERAL_RO_ATTR(mounted_time_sec);
>   F2FS_GENERAL_RO_ATTR(main_blkaddr);
>   F2FS_GENERAL_RO_ATTR(pending_discard);
> +F2FS_GENERAL_RO_ATTR(gc_mode);
>   #ifdef CONFIG_F2FS_STAT_FS
>   F2FS_STAT_ATTR(STAT_INFO, f2fs_stat_info, cp_foreground_calls, cp_count);
>   F2FS_STAT_ATTR(STAT_INFO, f2fs_stat_info, cp_background_calls, bg_cp_count);
> @@ -904,6 +921,7 @@ static struct attribute *f2fs_attrs[] = {
>   	ATTR_LIST(max_discard_issue_time),
>   	ATTR_LIST(discard_granularity),
>   	ATTR_LIST(pending_discard),
> +	ATTR_LIST(gc_mode),
>   	ATTR_LIST(batched_trim_sections),
>   	ATTR_LIST(ipu_policy),
>   	ATTR_LIST(min_ipu_util),