diff options
| author | Breno Leitao <leitao@debian.org> | 2026-08-05 07:52:36 -0700 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2026-08-10 11:47:20 -1000 |
| commit | a5bde5d8fde8a8cb28e59a672d5ddc5b9c1e7656 (patch) | |
| tree | 39f5b258386e1127d253d293194e9a2991bf3c34 /Documentation/gpu/drm-ras.rst | |
| download | linux-stable-a5bde5d8fde8a8cb28e59a672d5ddc5b9c1e7656.tar.gz linux-stable-a5bde5d8fde8a8cb28e59a672d5ddc5b9c1e7656.zip | |
workqueue: skip the node_nr_active update for non-unbound workqueuesgrafted
apply_wqattrs_commit() updates node_nr_active->max unconditionally.
wq->node_nr_active[] is only allocated for unbound workqueues, so guard
the call before per-cpu workqueues start using this path.
No functional change: only unbound workqueues reach apply_wqattrs_*()
today.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'Documentation/gpu/drm-ras.rst')
| -rw-r--r-- | Documentation/gpu/drm-ras.rst | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/Documentation/gpu/drm-ras.rst b/Documentation/gpu/drm-ras.rst new file mode 100644 index 000000000..83c21853b --- /dev/null +++ b/Documentation/gpu/drm-ras.rst @@ -0,0 +1,113 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +============================ +DRM RAS over Generic Netlink +============================ + +The DRM RAS (Reliability, Availability, Serviceability) interface provides a +standardized way for GPU/accelerator drivers to expose error counters and +other reliability nodes to user space via Generic Netlink. This allows +diagnostic tools, monitoring daemons, or test infrastructure to query hardware +health in a uniform way across different DRM drivers. + +Key Goals: + +* Provide a standardized RAS solution for GPU and accelerator drivers, enabling + data center monitoring and reliability operations. +* Implement a single drm-ras Generic Netlink family to meet modern Netlink YAML + specifications and centralize all RAS-related communication in one namespace. +* Support a basic error counter interface, addressing the immediate, essential + monitoring needs. +* Offer a flexible, future-proof interface that can be extended to support + additional types of RAS data in the future. +* Allow multiple nodes per driver, enabling drivers to register separate + nodes for different IP blocks, sub-blocks, or other logical subdivisions + as applicable. + +.. contents:: + +Nodes +===== + +Nodes are logical abstractions representing an error type or error source within +the device. Currently, only error counter nodes is supported. + +Drivers are responsible for registering and unregistering nodes via the +`drm_ras_node_register()` and `drm_ras_node_unregister()` APIs. + +Node Management +------------------- + +.. kernel-doc:: drivers/gpu/drm/drm_ras.c + :doc: DRM RAS Node Management +.. kernel-doc:: drivers/gpu/drm/drm_ras.c + :internal: + +Generic Netlink Usage +===================== + +The interface is implemented as a Generic Netlink family named ``drm-ras``. +User space tools can: + +* List registered nodes with the ``list-nodes`` command. +* List all error counters in an node with the ``get-error-counter`` command with ``node-id`` + as a parameter. +* Query specific error counter values with the ``get-error-counter`` command, using both + ``node-id`` and ``error-id`` as parameters. +* Clear specific error counters with the ``clear-error-counter`` command, using both + ``node-id`` and ``error-id`` as parameters. + +YAML-based Interface +-------------------- + +The interface is described in a YAML specification ``Documentation/netlink/specs/drm_ras.yaml`` + +This YAML is used to auto-generate user space bindings via +``tools/net/ynl/pyynl/ynl_gen_c.py``, and drives the structure of netlink +attributes and operations. + +Usage Notes +----------- + +* User space must first enumerate nodes to obtain their IDs. +* Node IDs or Node names can be used for all further queries, such as error counters. +* Error counters can be queried by either the Error ID or Error name. +* Query Parameters should be defined as part of the uAPI to ensure user interface stability. +* The interface supports future extension by adding new node types and + additional attributes. + +Example: List nodes using ynl + +.. code-block:: bash + + sudo ynl --family drm_ras --dump list-nodes + [{'device-name': '0000:03:00.0', + 'node-id': 0, + 'node-name': 'correctable-errors', + 'node-type': 'error-counter'}, + {'device-name': '0000:03:00.0', + 'node-id': 1, + 'node-name': 'uncorrectable-errors', + 'node-type': 'error-counter'}] + +Example: List all error counters using ynl + +.. code-block:: bash + + sudo ynl --family drm_ras --dump get-error-counter --json '{"node-id":0}' + [{'error-id': 1, 'error-name': 'error_name1', 'error-value': 0}, + {'error-id': 2, 'error-name': 'error_name2', 'error-value': 0}] + +Example: Query an error counter for a given node + +.. code-block:: bash + + sudo ynl --family drm_ras --do get-error-counter --json '{"node-id":0, "error-id":1}' + {'error-id': 1, 'error-name': 'error_name1', 'error-value': 0} + +Example: Clear an error counter for a given node + +.. code-block:: bash + + sudo ynl --family drm_ras --do clear-error-counter --json '{"node-id":0, "error-id":1}' + None |
