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Diffstat (limited to 'Documentation/filesystems/f2fs.txt')
| -rw-r--r-- | Documentation/filesystems/f2fs.txt | 54 |
1 files changed, 52 insertions, 2 deletions
diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt index 3cd27bed634..51afba17bba 100644 --- a/Documentation/filesystems/f2fs.txt +++ b/Documentation/filesystems/f2fs.txt @@ -119,6 +119,13 @@ active_logs=%u Support configuring the number of active logs. In the Default number is 6. disable_ext_identify Disable the extension list configured by mkfs, so f2fs does not aware of cold files such as media files. +inline_xattr Enable the inline xattrs feature. +inline_data Enable the inline data feature: New created small(<~3.4k) + files can be written into inode block. +flush_merge Merge concurrent cache_flush commands as much as possible + to eliminate redundant command issues. If the underlying + device handles the cache_flush command relatively slowly, + recommend to enable this option. ================================================================================ DEBUGFS ENTRIES @@ -164,6 +171,47 @@ Files in /sys/fs/f2fs/<devname> gc_idle = 1 will select the Cost Benefit approach & setting gc_idle = 2 will select the greedy aproach. + reclaim_segments This parameter controls the number of prefree + segments to be reclaimed. If the number of prefree + segments is larger than the number of segments + in the proportion to the percentage over total + volume size, f2fs tries to conduct checkpoint to + reclaim the prefree segments to free segments. + By default, 5% over total # of segments. + + max_small_discards This parameter controls the number of discard + commands that consist small blocks less than 2MB. + The candidates to be discarded are cached until + checkpoint is triggered, and issued during the + checkpoint. By default, it is disabled with 0. + + ipu_policy This parameter controls the policy of in-place + updates in f2fs. There are five policies: + 0: F2FS_IPU_FORCE, 1: F2FS_IPU_SSR, + 2: F2FS_IPU_UTIL, 3: F2FS_IPU_SSR_UTIL, + 4: F2FS_IPU_DISABLE. + + min_ipu_util This parameter controls the threshold to trigger + in-place-updates. The number indicates percentage + of the filesystem utilization, and used by + F2FS_IPU_UTIL and F2FS_IPU_SSR_UTIL policies. + + max_victim_search This parameter controls the number of trials to + find a victim segment when conducting SSR and + cleaning operations. The default value is 4096 + which covers 8GB block address range. + + dir_level This parameter controls the directory level to + support large directory. If a directory has a + number of files, it can reduce the file lookup + latency by increasing this dir_level value. + Otherwise, it needs to decrease this value to + reduce the space overhead. The default value is 0. + + ram_thresh This parameter controls the memory footprint used + by free nids and cached nat entries. By default, + 10 is set, which indicates 10 MB / 1 GB RAM. + ================================================================================ USAGE ================================================================================ @@ -413,9 +461,11 @@ The number of blocks and buckets are determined by, # of blocks in level #n = | `- 4, Otherwise - ,- 2^n, if n < MAX_DIR_HASH_DEPTH / 2, + ,- 2^(n + dir_level), + | if n + dir_level < MAX_DIR_HASH_DEPTH / 2, # of buckets in level #n = | - `- 2^((MAX_DIR_HASH_DEPTH / 2) - 1), Otherwise + `- 2^((MAX_DIR_HASH_DEPTH / 2) - 1), + Otherwise When F2FS finds a file name in a directory, at first a hash value of the file name is calculated. Then, F2FS scans the hash table in level #0 to find the |