summaryrefslogtreecommitdiff
path: root/Documentation/ABI/testing/sysfs-fs-ext4
blob: f22ac0872ae8de41a44406edfab71384d54b830a (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
What:		/sys/fs/ext4/<disk>/mb_stats
Date:		March 2008
Contact:	"Theodore Ts'o" <tytso@mit.edu>
Description:
		 Controls whether the multiblock allocator should
		 collect statistics, which are shown during the unmount.
		 1 means to collect statistics, 0 means not to collect
		 statistics

What:		/sys/fs/ext4/<disk>/mb_group_prealloc
Date:		March 2008
Contact:	"Theodore Ts'o" <tytso@mit.edu>
Description:
		The multiblock allocator will round up allocation
		requests to a multiple of this tuning parameter if the
		stripe size is not set in the ext4 superblock

What:		/sys/fs/ext4/<disk>/mb_max_to_scan
Date:		March 2008
Contact:	"Theodore Ts'o" <tytso@mit.edu>
Description:
		The maximum number of extents the multiblock allocator
		will search to find the best extent

What:		/sys/fs/ext4/<disk>/mb_min_to_scan
Date:		March 2008
Contact:	"Theodore Ts'o" <tytso@mit.edu>
Description:
		The minimum number of extents the multiblock allocator
		will search to find the best extent

What:		/sys/fs/ext4/<disk>/mb_order2_req
Date:		March 2008
Contact:	"Theodore Ts'o" <tytso@mit.edu>
Description:
		Tuning parameter which controls the minimum size for 
		requests (as a power of 2) where the buddy cache is
		used

What:		/sys/fs/ext4/<disk>/mb_stream_req
Date:		March 2008
Contact:	"Theodore Ts'o" <tytso@mit.edu>
Description:
		Files which have fewer blocks than this tunable
		parameter will have their blocks allocated out of a
		block group specific preallocation pool, so that small
		files are packed closely together.  Each large file
		 will have its blocks allocated out of its own unique
		 preallocation pool.

What:		/sys/fs/ext4/<disk>/inode_readahead_blks
Date:		March 2008
Contact:	"Theodore Ts'o" <tytso@mit.edu>
Description:
		Tuning parameter which controls the maximum number of
		inode table blocks that ext4's inode table readahead
		algorithm will pre-read into the buffer cache

What:		/sys/fs/ext4/<disk>/delayed_allocation_blocks
Date:		March 2008
Contact:	"Theodore Ts'o" <tytso@mit.edu>
Description:
		This file is read-only and shows the number of blocks
		that are dirty in the page cache, but which do not
		have their location in the filesystem allocated yet.

What:		/sys/fs/ext4/<disk>/lifetime_write_kbytes
Date:		March 2008
Contact:	"Theodore Ts'o" <tytso@mit.edu>
Description:
		This file is read-only and shows the number of kilobytes
		of data that have been written to this filesystem since it was
		created.

What:		/sys/fs/ext4/<disk>/session_write_kbytes
Date:		March 2008
Contact:	"Theodore Ts'o" <tytso@mit.edu>
Description:
		This file is read-only and shows the number of
		kilobytes of data that have been written to this
		filesystem since it was mounted.

What:		/sys/fs/ext4/<disk>/inode_goal
Date:		June 2008
Contact:	"Theodore Ts'o" <tytso@mit.edu>
Description:
		Tuning parameter which (if non-zero) controls the goal
		inode used by the inode allocator in preference to
		all other allocation heuristics.  This is intended for
		debugging use only, and should be 0 on production
		systems.

What:		/sys/fs/ext4/<disk>/max_writeback_mb_bump
Date:		September 2009
Contact:	"Theodore Ts'o" <tytso@mit.edu>
Description:
		The maximum number of megabytes the writeback code will
		try to write out before move on to another inode.