linux/Documentation/ABI/testing/sysfs-class-bdi
Mauro Carvalho Chehab 8a60958923 ABI: sysfs-class-bdi: use What: to describe each property
Instead of listing all bdi entries inside the description, add
one entry for each, just like the remaining ABI files.

That allows get_abi.pl script to properly parse it.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/77e5904dfd275ed2670cd13779e5ef1da96e355c.1632750608.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-28 12:48:15 +02:00

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What: /sys/class/bdi/<bdi>/
Date: January 2008
Contact: Peter Zijlstra <a.p.zijlstra@chello.nl>
Description:
Provide a place in sysfs for the backing_dev_info object. This allows
setting and retrieving various BDI specific variables.
The <bdi> identifier can be either of the following:
MAJOR:MINOR
Device number for block devices, or value of st_dev on
non-block filesystems which provide their own BDI, such as NFS
and FUSE.
MAJOR:MINOR-fuseblk
Value of st_dev on fuseblk filesystems.
default
The default backing dev, used for non-block device backed
filesystems which do not provide their own BDI.
What: /sys/class/bdi/<bdi>/read_ahead_kb
Date: January 2008
Contact: Peter Zijlstra <a.p.zijlstra@chello.nl>
Description:
Size of the read-ahead window in kilobytes
(read-write)
What: /sys/class/bdi/<bdi>/min_ratio
Date: January 2008
Contact: Peter Zijlstra <a.p.zijlstra@chello.nl>
Description:
Under normal circumstances each device is given a part of the
total write-back cache that relates to its current average
writeout speed in relation to the other devices.
The 'min_ratio' parameter allows assigning a minimum
percentage of the write-back cache to a particular device.
For example, this is useful for providing a minimum QoS.
(read-write)
What: /sys/class/bdi/<bdi>/max_ratio
Date: January 2008
Contact: Peter Zijlstra <a.p.zijlstra@chello.nl>
Description:
Allows limiting a particular device to use not more than the
given percentage of the write-back cache. This is useful in
situations where we want to avoid one device taking all or
most of the write-back cache. For example in case of an NFS
mount that is prone to get stuck, or a FUSE mount which cannot
be trusted to play fair.
(read-write)
What: /sys/class/bdi/<bdi>/stable_pages_required
Date: January 2008
Contact: Peter Zijlstra <a.p.zijlstra@chello.nl>
Description:
If set, the backing device requires that all pages comprising a write
request must not be changed until writeout is complete.
(read-only)