[PATCH v3 23/24] fs/stlmfs: Document lazy mode and related mount option
From: Cristian Marussi <cristian.marussi@arm.com>
Date: 2026-03-29 16:35:30
Also in:
arm-scmi, linux-arm-kernel, linux-fsdevel, lkml
Subsystem:
documentation, the rest · Maintainers:
Jonathan Corbet, Linus Torvalds
Document optional lazy enumeration behaviour and related mount option. Cc: Jonathan Corbet <corbet@lwn.net> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: linux-doc@vger.kernel.org Signed-off-by: Cristian Marussi <cristian.marussi@arm.com> --- Documentation/filesystems/stlmfs.rst | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-)
diff --git a/Documentation/filesystems/stlmfs.rst b/Documentation/filesystems/stlmfs.rst
index a775da24f320..9a5c8bf588c8 100644
--- a/Documentation/filesystems/stlmfs.rst
+++ b/Documentation/filesystems/stlmfs.rst@@ -74,8 +74,12 @@ Design STLMFS is a pseudo filesystem used to expose ARM SCMI Telemetry data discovered dynamically at run-time via SCMI. -Inodes are all dynamically created at mount-time from a dedicated -kmem_cache based on the gathered available SCMI Telemetry information. +Normally all of the top level file/inodes are dynamically created at +mount-time from a dedicated kmem_cache based on the gathered available +SCMI Telemetry information, but it is possible to enable a lazy enumeration +and FS population mode that delays SCMI Telemetry resources enumerations +and related FS population till the moment a user steps into the related FS +subdirectories: *des/* *groups/* and *components/*. Since inodes represent the discovered Telemetry entities, which in turn are statically defined at the platform level and immutable throughout the same
@@ -105,6 +109,19 @@ The filesystem can be typically mounted with:: mount -t stlmfs none /sys/fs/arm_telemetry +It is possible to mount it in lazy-mode by using the *lazy* mount option:: + + mount -t stlmfs -o lazy none /sys/fs/arm_telemetry + +In this latter case, the des/ groups/ and components/ directory will be +created empty at mount-time and only filled later when 'walked in'. + +This allows a user to benefit from a lazy enumeration scheme of the SCMI +Telemetry resources by delaying such, usually expensive, message exchanges +to the last possible moment: ideally, even never, if using some of the +other alternative binary interfaces that does not need any resource +enumeration at all. + It will proceed to create a top subdirectory for each of the discovered SCMI Telemetry instances named as 'tlm_<N>' under which it will create the following directory structure::
--
2.53.0