| Peter Zijlstra | cf0ca9f | 2008-04-30 00:54:32 -0700 | [diff] [blame] | 1 | What: /sys/class/bdi/<bdi>/ |
| 2 | Date: January 2008 |
| 3 | Contact: Peter Zijlstra <a.p.zijlstra@chello.nl> |
| 4 | Description: |
| 5 | |
| 6 | Provide a place in sysfs for the backing_dev_info object. |
| 7 | This allows us to see and set the various BDI specific variables. |
| 8 | |
| 9 | The <bdi> identifier can be either of the following: |
| 10 | |
| 11 | MAJOR: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 | |
| 17 | default |
| 18 | |
| 19 | The default backing dev, used for non-block device backed |
| 20 | filesystems which do not provide their own BDI. |
| 21 | |
| 22 | Files under /sys/class/bdi/<bdi>/ |
| 23 | --------------------------------- |
| 24 | |
| 25 | read_ahead_kb (read-write) |
| 26 | |
| 27 | Size of the read-ahead window in kilobytes |
| 28 | |
| 29 | reclaimable_kb (read-only) |
| 30 | |
| 31 | Reclaimable (dirty or unstable) memory destined for writeback |
| 32 | to this device |
| 33 | |
| 34 | writeback_kb (read-only) |
| 35 | |
| 36 | Memory currently under writeback to this device |
| 37 | |
| 38 | dirty_kb (read-only) |
| 39 | |
| 40 | Global threshold for reclaimable + writeback memory |
| 41 | |
| 42 | bdi_dirty_kb (read-only) |
| 43 | |
| 44 | Current threshold on this BDI for reclaimable + writeback |
| 45 | memory |
| 46 | |
| Peter Zijlstra | 189d3c4 | 2008-04-30 00:54:35 -0700 | [diff] [blame] | 47 | min_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. |
| Peter Zijlstra | a42dde0 | 2008-04-30 00:54:36 -0700 | [diff] [blame^] | 52 | If min_ratio would become larger than the current max_ratio, |
| 53 | then also EINVAL is returned. The default is zero |
| 54 | |
| 55 | max_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 |