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diff --git a/Documentation/networking/devlink/devlink-resource.rst b/Documentation/networking/devlink/devlink-resource.rst new file mode 100644 index 0000000000..3d5ae51e65 --- /dev/null +++ b/Documentation/networking/devlink/devlink-resource.rst @@ -0,0 +1,76 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================ +Devlink Resource +================ + +``devlink`` provides the ability for drivers to register resources, which +can allow administrators to see the device restrictions for a given +resource, as well as how much of the given resource is currently +in use. Additionally, these resources can optionally have configurable size. +This could enable the administrator to limit the number of resources that +are used. + +For example, the ``netdevsim`` driver enables ``/IPv4/fib`` and +``/IPv4/fib-rules`` as resources to limit the number of IPv4 FIB entries and +rules for a given device. + +Resource Ids +============ + +Each resource is represented by an id, and contains information about its +current size and related sub resources. To access a sub resource, you +specify the path of the resource. For example ``/IPv4/fib`` is the id for +the ``fib`` sub-resource under the ``IPv4`` resource. + +Generic Resources +================= + +Generic resources are used to describe resources that can be shared by multiple +device drivers and their description must be added to the following table: + +.. list-table:: List of Generic Resources + :widths: 10 90 + + * - Name + - Description + * - ``physical_ports`` + - A limited capacity of physical ports that the switch ASIC can support + +example usage +------------- + +The resources exposed by the driver can be observed, for example: + +.. code:: shell + + $devlink resource show pci/0000:03:00.0 + pci/0000:03:00.0: + name kvd size 245760 unit entry + resources: + name linear size 98304 occ 0 unit entry size_min 0 size_max 147456 size_gran 128 + name hash_double size 60416 unit entry size_min 32768 size_max 180224 size_gran 128 + name hash_single size 87040 unit entry size_min 65536 size_max 212992 size_gran 128 + +Some resource's size can be changed. Examples: + +.. code:: shell + + $devlink resource set pci/0000:03:00.0 path /kvd/hash_single size 73088 + $devlink resource set pci/0000:03:00.0 path /kvd/hash_double size 74368 + +The changes do not apply immediately, this can be validated by the 'size_new' +attribute, which represents the pending change in size. For example: + +.. code:: shell + + $devlink resource show pci/0000:03:00.0 + pci/0000:03:00.0: + name kvd size 245760 unit entry size_valid false + resources: + name linear size 98304 size_new 147456 occ 0 unit entry size_min 0 size_max 147456 size_gran 128 + name hash_double size 60416 unit entry size_min 32768 size_max 180224 size_gran 128 + name hash_single size 87040 unit entry size_min 65536 size_max 212992 size_gran 128 + +Note that changes in resource size may require a device reload to properly +take effect. |