f2fs: export compress_percent and compress_watermark entries

This patch export below sysfs entries for better control cached
compress page count.

/sys/fs/f2fs/<disk>/compress_watermark
/sys/fs/f2fs/<disk>/compress_percent
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Documentation/ABI/testing/sysfs-fs-f2fs

@@ -729,3 +729,20 @@ What:		/sys/fs/f2fs/<disk>/last_age_weight
 Date:		January 2023
 Contact:	"Ping Xiong" <xiongping1@xiaomi.com>
 Description:	When DATA SEPARATION is on, it controls the weight of last data block age.
+
+What:		/sys/fs/f2fs/<disk>/compress_watermark
+Date:		February 2023
+Contact:	"Yangtao Li" <frank.li@vivo.com>
+Description:	When compress cache is on, it controls free memory watermark
+		in order to limit caching compress page. If free memory is lower
+		than watermark, then deny caching compress page. The value should be in
+		range of (0, 100], by default it was initialized as 20(%).
+
+What:		/sys/fs/f2fs/<disk>/compress_percent
+Date:		February 2023
+Contact:	"Yangtao Li" <frank.li@vivo.com>
+Description:	When compress cache is on, it controls cached page
+		percent(compress pages / free_ram) in order to limit caching compress page.
+		If cached page percent exceed threshold, then deny caching compress page.
+		The value should be in range of (0, 100], by default it was initialized
+		as 20(%).

fs/f2fs/sysfs.c

@@ -598,6 +598,20 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
 		sbi->compr_new_inode = 0;
 		return count;
 	}
+
+	if (!strcmp(a->attr.name, "compress_percent")) {
+		if (t == 0 || t > 100)
+			return -EINVAL;
+		*ui = t;
+		return count;
+	}
+
+	if (!strcmp(a->attr.name, "compress_watermark")) {
+		if (t == 0 || t > 100)
+			return -EINVAL;
+		*ui = t;
+		return count;
+	}
 #endif
 
 	if (!strcmp(a->attr.name, "atgc_candidate_ratio")) {
@@ -950,6 +964,8 @@ F2FS_FEATURE_RO_ATTR(compression);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, compr_written_block, compr_written_block);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, compr_saved_block, compr_saved_block);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, compr_new_inode, compr_new_inode);
+F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, compress_percent, compress_percent);
+F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, compress_watermark, compress_watermark);
 #endif
 F2FS_FEATURE_RO_ATTR(pin_file);
 
@@ -1057,6 +1073,8 @@ static struct attribute *f2fs_attrs[] = {
 	ATTR_LIST(compr_written_block),
 	ATTR_LIST(compr_saved_block),
 	ATTR_LIST(compr_new_inode),
+	ATTR_LIST(compress_percent),
+	ATTR_LIST(compress_watermark),
 #endif
 	/* For ATGC */
 	ATTR_LIST(atgc_candidate_ratio),