1What:		/sys/class/bdi/<bdi>/
2Date:		January 2008
3Contact:	Peter Zijlstra <[email protected]>
4Description:
5
6Provide a place in sysfs for the backing_dev_info object.
7This allows us to see and set the various BDI specific variables.
8
9The <bdi> identifier can be either of the following:
10
11MAJOR:MINOR
12
13	Device number for block devices, or value of st_dev on
14	non-block filesystems which provide their own BDI, such as NFS
15	and FUSE.
16
17default
18
19	The default backing dev, used for non-block device backed
20	filesystems which do not provide their own BDI.
21
22Files under /sys/class/bdi/<bdi>/
23---------------------------------
24
25read_ahead_kb (read-write)
26
27	Size of the read-ahead window in kilobytes
28
29reclaimable_kb (read-only)
30
31	Reclaimable (dirty or unstable) memory destined for writeback
32	to this device
33
34writeback_kb (read-only)
35
36	Memory currently under writeback to this device
37
38dirty_kb (read-only)
39
40	Global threshold for reclaimable + writeback memory
41
42bdi_dirty_kb (read-only)
43
44	Current threshold on this BDI for reclaimable + writeback
45	memory
46
47min_ratio (read-write)
48
49	Minimal percentage of global dirty threshold allocated to this
50	bdi.  If the value written to this file would make the the sum
51	of all min_ratio values exceed 100, then EINVAL is returned.
52	If min_ratio would become larger than the current max_ratio,
53	then also EINVAL is returned.  The default is zero
54
55max_ratio (read-write)
56
57	Maximal percentage of global dirty threshold allocated to this
58	bdi.  If max_ratio would become smaller than the current
59	min_ratio, then EINVAL is returned.  The default is 100
60