1 What: /sys/class/bdi/<bdi>/
2 Date: January 2008
3 Contact: Peter Zijlstra <a.p.zijlstra@ch
4 Description:
5
6 Provide a place in sysfs for the backing_dev_i
7 setting and retrieving various BDI specific va
8
9 The <bdi> identifier can be either of the foll
10
11 MAJOR:MINOR
12
13 Device number for block devices, or va
14 non-block filesystems which provide th
15 and FUSE.
16
17 MAJOR:MINOR-fuseblk
18
19 Value of st_dev on fuseblk filesystems
20
21 default
22
23 The default backing dev, used for non-
24 filesystems which do not provide their
25
26 What: /sys/class/bdi/<bdi>/read_ahea
27 Date: January 2008
28 Contact: Peter Zijlstra <a.p.zijlstra@ch
29 Description:
30 Size of the read-ahead window in kilob
31
32 (read-write)
33 What: /sys/class/bdi/<bdi>/min_ratio
34 Date: January 2008
35 Contact: Peter Zijlstra <a.p.zijlstra@ch
36 Description:
37 Under normal circumstances each device
38 total write-back cache that relates to
39 writeout speed in relation to the othe
40
41 The 'min_ratio' parameter allows assig
42 percentage of the write-back cache to
43 For example, this is useful for provid
44
45 (read-write)
46
47 What: /sys/class/bdi/<bdi>/min_ratio
48 Date: November 2022
49 Contact: Stefan Roesch <shr@devkernel.io
50 Description:
51 Under normal circumstances each device
52 total write-back cache that relates to
53 writeout speed in relation to the othe
54
55 The 'min_ratio_fine' parameter allows
56 of the write-back cache to a particula
57 expressed as part of 1 million. For ex
58 providing a minimum QoS.
59
60 (read-write)
61
62 What: /sys/class/bdi/<bdi>/max_ratio
63 Date: January 2008
64 Contact: Peter Zijlstra <a.p.zijlstra@ch
65 Description:
66 Allows limiting a particular device to
67 given percentage of the write-back cac
68 situations where we want to avoid one
69 most of the write-back cache. For exa
70 mount that is prone to get stuck, or a
71 be trusted to play fair.
72
73 (read-write)
74
75 What: /sys/class/bdi/<bdi>/max_ratio
76 Date: November 2022
77 Contact: Stefan Roesch <shr@devkernel.io
78 Description:
79 Allows limiting a particular device to
80 given value of the write-back cache.
81 of 1 million. This is useful in situat
82 one device taking all or most of the w
83 in case of an NFS mount that is prone
84 which cannot be trusted to play fair.
85
86 (read-write)
87
88 What: /sys/class/bdi/<bdi>/min_bytes
89 Date: October 2022
90 Contact: Stefan Roesch <shr@devkernel.io
91 Description:
92 Under normal circumstances each device
93 total write-back cache that relates to
94 writeout speed in relation to the othe
95
96 The 'min_bytes' parameter allows assig
97 percentage of the write-back cache to
98 expressed in bytes.
99 For example, this is useful for provid
100
101 (read-write)
102
103 What: /sys/class/bdi/<bdi>/max_bytes
104 Date: October 2022
105 Contact: Stefan Roesch <shr@devkernel.io
106 Description:
107 Allows limiting a particular device to
108 given 'max_bytes' of the write-back ca
109 situations where we want to avoid one
110 most of the write-back cache. For exa
111 mount that is prone to get stuck, a FU
112 trusted to play fair, or a nbd device.
113
114 (read-write)
115
116 What: /sys/class/bdi/<bdi>/strict_li
117 Date: October 2022
118 Contact: Stefan Roesch <shr@devkernel.io
119 Description:
120 Forces per-BDI checks for the share of
121 cache even before the global backgroun
122 is useful in situations where the glob
123 affordable for given relatively slow (
124 strictlimit on has no visible effect i
125
126 (read-write)
127 What: /sys/class/bdi/<bdi>/stable_pa
128 Date: January 2008
129 Contact: Peter Zijlstra <a.p.zijlstra@ch
130 Description:
131 If set, the backing device requires th
132 request must not be changed until writ
133
134 (read-only)
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