Documentation/ABI/testing/sysfs-fs-ext4

   1 What:           /sys/fs/ext4/<disk>/mb_stats
   2 Date:           March 2008
   3 Contact:        "Theodore Ts'o" <tytso@mit.edu>
   4 Description:
   5                  Controls whether the multiblock allocator should
   6                  collect statistics, which are shown during the unmount.
   7                  1 means to collect statistics, 0 means not to collect
   8                  statistics
   9
  10 What:           /sys/fs/ext4/<disk>/mb_group_prealloc
  11 Date:           March 2008
  12 Contact:        "Theodore Ts'o" <tytso@mit.edu>
  13 Description:
  14                 The multiblock allocator will round up allocation
  15                 requests to a multiple of this tuning parameter if the
  16                 stripe size is not set in the ext4 superblock
  17
  18 What:           /sys/fs/ext4/<disk>/mb_max_to_scan
  19 Date:           March 2008
  20 Contact:        "Theodore Ts'o" <tytso@mit.edu>
  21 Description:
  22                 The maximum number of extents the multiblock allocator
  23                 will search to find the best extent
  24
  25 What:           /sys/fs/ext4/<disk>/mb_min_to_scan
  26 Date:           March 2008
  27 Contact:        "Theodore Ts'o" <tytso@mit.edu>
  28 Description:
  29                 The minimum number of extents the multiblock allocator
  30                 will search to find the best extent
  31
  32 What:           /sys/fs/ext4/<disk>/mb_order2_req
  33 Date:           March 2008
  34 Contact:        "Theodore Ts'o" <tytso@mit.edu>
  35 Description:
  36                 Tuning parameter which controls the minimum size for
  37                 requests (as a power of 2) where the buddy cache is
  38                 used
  39
  40 What:           /sys/fs/ext4/<disk>/mb_stream_req
  41 Date:           March 2008
  42 Contact:        "Theodore Ts'o" <tytso@mit.edu>
  43 Description:
  44                 Files which have fewer blocks than this tunable
  45                 parameter will have their blocks allocated out of a
  46                 block group specific preallocation pool, so that small
  47                 files are packed closely together.  Each large file
  48                  will have its blocks allocated out of its own unique
  49                  preallocation pool.
  50
  51 What:           /sys/fs/ext4/<disk>/inode_readahead_blks
  52 Date:           March 2008
  53 Contact:        "Theodore Ts'o" <tytso@mit.edu>
  54 Description:
  55                 Tuning parameter which controls the maximum number of
  56                 inode table blocks that ext4's inode table readahead
  57                 algorithm will pre-read into the buffer cache
  58
  59 What:           /sys/fs/ext4/<disk>/delayed_allocation_blocks
  60 Date:           March 2008
  61 Contact:        "Theodore Ts'o" <tytso@mit.edu>
  62 Description:
  63                 This file is read-only and shows the number of blocks
  64                 that are dirty in the page cache, but which do not
  65                 have their location in the filesystem allocated yet.
  66
  67 What:           /sys/fs/ext4/<disk>/lifetime_write_kbytes
  68 Date:           March 2008
  69 Contact:        "Theodore Ts'o" <tytso@mit.edu>
  70 Description:
  71                 This file is read-only and shows the number of kilobytes
  72                 of data that have been written to this filesystem since it was
  73                 created.
  74
  75 What:           /sys/fs/ext4/<disk>/session_write_kbytes
  76 Date:           March 2008
  77 Contact:        "Theodore Ts'o" <tytso@mit.edu>
  78 Description:
  79                 This file is read-only and shows the number of
  80                 kilobytes of data that have been written to this
  81                 filesystem since it was mounted.
  82
  83 What:           /sys/fs/ext4/<disk>/inode_goal
  84 Date:           June 2008
  85 Contact:        "Theodore Ts'o" <tytso@mit.edu>
  86 Description:
  87                 Tuning parameter which (if non-zero) controls the goal
  88                 inode used by the inode allocator in preference to
  89                 all other allocation heuristics.  This is intended for
  90                 debugging use only, and should be 0 on production
  91                 systems.
  92
  93 What:           /sys/fs/ext4/<disk>/max_writeback_mb_bump
  94 Date:           September 2009
  95 Contact:        "Theodore Ts'o" <tytso@mit.edu>
  96 Description:
  97                 The maximum number of megabytes the writeback code will
  98                 try to write out before move on to another inode.