Document the lifetime, nolifetime and max_open_zones mount options
added for zoned rt file systems.
Also add documentation describing the max_open_zones sysfs attribute
exposed in /sys/fs/xfs/<dev>/zoned/
Fixes: 4e4d52075577 ("xfs: add the zoned space allocator")
Signed-off-by: Hans Holmberg <hans.holmberg@xxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: "Darrick J. Wong" <djwong@xxxxxxxxxx>
---
Resending this fix for v6.15-rc1
Added reviewed-by tags from Christoph and Darrick's reviews.
Documentation/admin-guide/xfs.rst | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/Documentation/admin-guide/xfs.rst b/Documentation/admin-guide/xfs.rst
index b67772cf36d6..c0a0501b610c 100644
--- a/Documentation/admin-guide/xfs.rst
+++ b/Documentation/admin-guide/xfs.rst
@@ -124,6 +124,14 @@ When mounting an XFS filesystem, the following options are accepted.
controls the size of each buffer and so is also relevant to
this case.
+ lifetime (default) or nolifetime
+ Enable data placement based on write life time hints provided
+ by the user. This turns on co-allocation of data of similar
+ life times when statistically favorable to reduce garbage
+ collection cost.
+
+ These options are only available for zoned rt file systems.
+
logbsize=value
Set the size of each in-memory log buffer. The size may be
specified in bytes, or in kilobytes with a "k" suffix.
@@ -143,6 +151,14 @@ When mounting an XFS filesystem, the following options are accepted.
optional, and the log section can be separate from the data
section or contained within it.
+ max_open_zones=value
+ Specify the max number of zones to keep open for writing on a
+ zoned rt device. Many open zones aids file data separation
+ but may impact performance on HDDs.
+
+ If ``max_open_zones`` is not specified, the value is determined
+ by the capabilities and the size of the zoned rt device.
+
noalign
Data allocations will not be aligned at stripe unit
boundaries. This is only relevant to filesystems created
@@ -542,3 +558,16 @@ The interesting knobs for XFS workqueues are as follows:
nice Relative priority of scheduling the threads. These are the
same nice levels that can be applied to userspace processes.
============ ===========
+
+Zoned Filesystems
+=================
+
+For zoned file systems, the following attribute is exposed in:
+
+ /sys/fs/xfs/<dev>/zoned/
+
+ max_open_zones (Min: 1 Default: Varies Max: UINTMAX)
+ This read-only attribute exposes the maximum number of open zones
+ available for data placement. The value is determined at mount time and
+ is limited by the capabilities of the backing zoned device, file system
+ size and the max_open_zones mount option.
--
2.34.1
