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  1. 03 Jun, 2021 35 commits
  3. 02 Jun, 2021 5 commits
    • David S. Miller's avatar
      Merge branch 'devlink-rate-objects' · 270d47dc
      David S. Miller authored 
      Dmytro Linkin says:

====================
devlink: rate objects API

Resending without RFC.

Currently kernel provides a way to change tx rate of single VF in
switchdev mode via tc-police action. When lots of VFs are configured
management of theirs rates becomes non-trivial task and some grouping
mechanism is required. Implementing such grouping in tc-police will bring
flow related limitations and unwanted complications, like:
- tc-police is a policer and there is a user request for a traffic
  shaper, so shared tc-police action is not suitable;
- flows requires net device to be placed on, means "groups" wouldn't
  have net device instance itself. Taking into the account previous
  point was reviewed a sollution, when representor have a policer and
  the driver use a shaper if qdisc contains group of VFs - such approach
  ugly, compilated and misleading;
- TC is ingress only, while configuring "other" side of the wire looks
  more like a "real" picture where shaping is outside of the steering
  world, similar to "ip link" command;

According to that devlink is the most appropriate place.

This series introduces devlink API for managing tx rate of single devlink
port or of a group by invoking callbacks (see below) of corresponding
driver. Also devlink port or a group can be added to the parent group,
where driver responsible to handle rates of a group elements. To achieve
all of that new rate object is added. It can be one of the two types:
- leaf - represents a single devlink port; created/destroyed by the
  driver and bound to the devlink port. As example, some driver may
  create leaf rate object for every devlink port associated with VF.
  Since leaf have 1to1 mapping to it's devlink port, in user space it is
  referred as pci/<bus_addr>/<port_index>;
- node - represents a group of rate objects; created/deleted by request
  from the userspace; initially empty (no rate objects added). In
  userspace it is referred as pci/<bus_addr>/<node_name>, where node name
  can be any, except decimal number, to avoid collisions with leafs.

devlink_ops extended with following callbacks:
- rate_{leaf|node}_tx_{share|max}_set
- rate_node_{new|del}
- rate_{leaf|node}_parent_set

KAPI provides:
- creation/destruction of the leaf rate object associated with devlink
  port
- destruction of rate nodes to allow a vendor driver to free allocated
  resources on driver removal or due to the other reasons when nodes
  destruction required

UAPI provides:
- dumping all or single rate objects
- setting tx_{share|max} of rate object of any type
- creating/deleting node rate object
- setting/unsetting parent of any rate object

Added devlink rate object support for netdevsim driver

Issues/open questions:
- Does user need DEVLINK_CMD_RATE_DEL_ALL_CHILD command to clean all
  children of particular parent node? For example:
  $ devlink port function rate flush netdevsim/netdevsim10/group
- priv pointer passed to the callbacks is a source of bugs; in leaf case
  driver can embed rate object into internal structure and use
  container_of() on it; in node case it cannot be done since nodes are
  created from userspace

v1->v2:
- fixed kernel-doc for devlink_rate_leaf_{create|destroy}()
- s/func/function/ for all devlink port command occurences

v2->v3:
- devlink:
  - added devlink_rate_nodes_destroy() function
- netdevsim:
  - added call of devlink_rate_nodes_destroy() function
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      270d47dc
    • Dmytro Linkin's avatar
      Documentation: devlink rate objects · b62767e7
      Dmytro Linkin authored 
      Add devlink rate objects section at devlink port documentation.
Add devlink rate support info at netdevsim devlink documentation.
Signed-off-by: default avatarDmytro Linkin <dlinkin@nvidia.com>
Reviewed-by: default avatarJiri Pirko <jiri@nvidia.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      b62767e7
    • Dmytro Linkin's avatar
      selftest: netdevsim: Add devlink rate grouping test · 1a9c0482
      Dmytro Linkin authored 
      Test verifies that netdevsim correctly implements devlink ops callbacks
that set node as a parent of devlink leaf or node rate object.
Co-developed-by: default avatarVlad Buslov <vladbu@nvidia.com>
Signed-off-by: default avatarVlad Buslov <vladbu@nvidia.com>
Signed-off-by: default avatarDmytro Linkin <dlinkin@nvidia.com>
Reviewed-by: default avatarJiri Pirko <jiri@nvidia.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      1a9c0482
    • Dmytro Linkin's avatar
      netdevsim: Allow setting parent node of rate objects · f3d101b4
      Dmytro Linkin authored 
      Implement new devlink ops that allow setting rate node as a parent for
devlink port (leaf) or another devlink node through devlink API.
Expose parent names to netdevsim debugfs in read only mode.
Co-developed-by: default avatarVlad Buslov <vladbu@nvidia.com>
Signed-off-by: default avatarVlad Buslov <vladbu@nvidia.com>
Signed-off-by: default avatarDmytro Linkin <dlinkin@nvidia.com>
Reviewed-by: default avatarJiri Pirko <jiri@nvidia.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      f3d101b4
    • Dmytro Linkin's avatar
      devlink: Allow setting parent node of rate objects · d7555984
      Dmytro Linkin authored 
      Refactor DEVLINK_CMD_RATE_{GET|SET} command handlers to support setting
a node as a parent for another rate object (leaf or node) by means of
new attribute DEVLINK_ATTR_RATE_PARENT_NODE_NAME. Extend devlink ops
with new callbacks rate_{leaf|node}_parent_set() to set node as a parent
for rate object to allow supporting drivers to implement rate grouping
through devlink. Driver implementations are allowed to support leafs
or node children only. Invoking callback with NULL as parent should be
threated by the driver as unset parent action.
Extend rate object struct with reference counter to disallow deleting a
node with any child pointing to it. User should unset parent for the
child explicitly.

Example:

$ devlink port function rate add netdevsim/netdevsim10/group1

$ devlink port function rate add netdevsim/netdevsim10/group2

$ devlink port function rate set netdevsim/netdevsim10/group1 parent group2

$ devlink port function rate show netdevsim/netdevsim10/group1
netdevsim/netdevsim10/group1: type node parent group2

$ devlink port function rate set netdevsim/netdevsim10/group1 noparent
Co-developed-by: default avatarVlad Buslov <vladbu@nvidia.com>
Signed-off-by: default avatarVlad Buslov <vladbu@nvidia.com>
Signed-off-by: default avatarDmytro Linkin <dlinkin@nvidia.com>
Reviewed-by: default avatarJiri Pirko <jiri@nvidia.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      d7555984
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