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[RFC,v4,17/20] mm: document /sys/class/bdi/<bdi>/max_ratio_fine knob

Message ID 20221119005215.3052436-18-shr@devkernel.io (mailing list archive)
State New
Headers show
Series mm/block: add bdi sysfs knobs | expand

Commit Message

Stefan Roesch Nov. 19, 2022, 12:52 a.m. UTC 
This documents the new /sys/class/bdi/<bdi>/max_ratio_fine knob.

Signed-off-by: Stefan Roesch <shr@devkernel.io>
---
 Documentation/ABI/testing/sysfs-class-bdi | 13 +++++++++++++
 1 file changed, 13 insertions(+)
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Patch

diff --git a/Documentation/ABI/testing/sysfs-class-bdi b/Documentation/ABI/testing/sysfs-class-bdi
index bec996e29565..34d2e5489c74 100644
--- a/Documentation/ABI/testing/sysfs-class-bdi
+++ b/Documentation/ABI/testing/sysfs-class-bdi
@@ -57,6 +57,19 @@  Description:
 
 	(read-write)
 
+What:		/sys/class/bdi/<bdi>/max_ratio_fine
+Date:		November 2022
+Contact:	Stefan Roesch <shr@devkernel.io>
+Description:
+	Allows limiting a particular device to use not more than the
+	given value of the write-back cache.  The value is given as part
+    of 1 million. 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>/min_bytes
 Date:		October 2022
 Contact:	Stefan Roesch <shr@devkernel.io>