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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2008-04-30 11:54:35 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-30 19:29:50 +0400 |
| commit | 189d3c4a94ef19fca2a71a6a336e9fda900e25e7 (patch) | |
| tree | 75c0de871fe9922885a2fa073f15806d829342fa /Documentation/ABI | |
| parent | b6f2fcbcfca9db2bd7aa24940224fcd3bbdbb8aa (diff) | |
| download | linux-189d3c4a94ef19fca2a71a6a336e9fda900e25e7.tar.xz | |
mm: bdi: allow setting a minimum for the bdi dirty limit
Under normal circumstances each device is given a part of the total write-back
cache that relates to its current avg writeout speed in relation to the other
devices.
min_ratio - allows one to assign a minimum portion of the write-back cache to
a particular device. This is useful in situations where you might want to
provide a minimum QoS. (One request for this feature came from flash based
storage people who wanted to avoid writing out at all costs - they of course
needed some pdflush hacks as well)
max_ratio - allows one to assign a maximum portion of the dirty limit to a
particular device. This is useful in situations where you want to avoid one
device taking all or most of the write-back cache. Eg. an NFS mount that is
prone to get stuck, or a FUSE mount which you don't trust to play fair.
Add "min_ratio" to /sys/class/bdi. This indicates the minimum percentage of
the global dirty threshold allocated to this bdi.
[mszeredi@suse.cz]
- fix parsing in min_ratio_store()
- document new sysfs attribute
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-class-bdi | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-bdi b/Documentation/ABI/testing/sysfs-class-bdi index b800cdda40bb..b9e8a9368dc6 100644 --- a/Documentation/ABI/testing/sysfs-class-bdi +++ b/Documentation/ABI/testing/sysfs-class-bdi @@ -44,3 +44,9 @@ bdi_dirty_kb (read-only) Current threshold on this BDI for reclaimable + writeback memory +min_ratio (read-write) + + Minimal percentage of global dirty threshold allocated to this + bdi. If the value written to this file would make the the sum + of all min_ratio values exceed 100, then EINVAL is returned. + The default is zero |