1cf0ca9feSPeter ZijlstraWhat:		/sys/class/bdi/<bdi>/
2cf0ca9feSPeter ZijlstraDate:		January 2008
3cf0ca9feSPeter ZijlstraContact:	Peter Zijlstra <a.p.zijlstra@chello.nl>
4cf0ca9feSPeter ZijlstraDescription:
5cf0ca9feSPeter Zijlstra
6cf0ca9feSPeter ZijlstraProvide a place in sysfs for the backing_dev_info object.
7cf0ca9feSPeter ZijlstraThis allows us to see and set the various BDI specific variables.
8cf0ca9feSPeter Zijlstra
9cf0ca9feSPeter ZijlstraThe <bdi> identifier can be either of the following:
10cf0ca9feSPeter Zijlstra
11cf0ca9feSPeter ZijlstraMAJOR:MINOR
12cf0ca9feSPeter Zijlstra
13cf0ca9feSPeter Zijlstra	Device number for block devices, or value of st_dev on
14cf0ca9feSPeter Zijlstra	non-block filesystems which provide their own BDI, such as NFS
15cf0ca9feSPeter Zijlstra	and FUSE.
16cf0ca9feSPeter Zijlstra
17cf0ca9feSPeter Zijlstradefault
18cf0ca9feSPeter Zijlstra
19cf0ca9feSPeter Zijlstra	The default backing dev, used for non-block device backed
20cf0ca9feSPeter Zijlstra	filesystems which do not provide their own BDI.
21cf0ca9feSPeter Zijlstra
22cf0ca9feSPeter ZijlstraFiles under /sys/class/bdi/<bdi>/
23cf0ca9feSPeter Zijlstra---------------------------------
24cf0ca9feSPeter Zijlstra
25cf0ca9feSPeter Zijlstraread_ahead_kb (read-write)
26cf0ca9feSPeter Zijlstra
27cf0ca9feSPeter Zijlstra	Size of the read-ahead window in kilobytes
28cf0ca9feSPeter Zijlstra
29cf0ca9feSPeter Zijlstrareclaimable_kb (read-only)
30cf0ca9feSPeter Zijlstra
31cf0ca9feSPeter Zijlstra	Reclaimable (dirty or unstable) memory destined for writeback
32cf0ca9feSPeter Zijlstra	to this device
33cf0ca9feSPeter Zijlstra
34cf0ca9feSPeter Zijlstrawriteback_kb (read-only)
35cf0ca9feSPeter Zijlstra
36cf0ca9feSPeter Zijlstra	Memory currently under writeback to this device
37cf0ca9feSPeter Zijlstra
38cf0ca9feSPeter Zijlstradirty_kb (read-only)
39cf0ca9feSPeter Zijlstra
40cf0ca9feSPeter Zijlstra	Global threshold for reclaimable + writeback memory
41cf0ca9feSPeter Zijlstra
42cf0ca9feSPeter Zijlstrabdi_dirty_kb (read-only)
43cf0ca9feSPeter Zijlstra
44cf0ca9feSPeter Zijlstra	Current threshold on this BDI for reclaimable + writeback
45cf0ca9feSPeter Zijlstra	memory
46cf0ca9feSPeter Zijlstra
47189d3c4aSPeter Zijlstramin_ratio (read-write)
48189d3c4aSPeter Zijlstra
49189d3c4aSPeter Zijlstra	Minimal percentage of global dirty threshold allocated to this
50189d3c4aSPeter Zijlstra	bdi.  If the value written to this file would make the the sum
51189d3c4aSPeter Zijlstra	of all min_ratio values exceed 100, then EINVAL is returned.
52*a42dde04SPeter Zijlstra	If min_ratio would become larger than the current max_ratio,
53*a42dde04SPeter Zijlstra	then also EINVAL is returned.  The default is zero
54*a42dde04SPeter Zijlstra
55*a42dde04SPeter Zijlstramax_ratio (read-write)
56*a42dde04SPeter Zijlstra
57*a42dde04SPeter Zijlstra	Maximal percentage of global dirty threshold allocated to this
58*a42dde04SPeter Zijlstra	bdi.  If max_ratio would become smaller than the current
59*a42dde04SPeter Zijlstra	min_ratio, then EINVAL is returned.  The default is 100
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