[PATCH net-next 01/15] devlink: Extend devlink rate API with traffic classes bandwidth management

Tariq Toukan
2025-02-09T10:19:01Z

From: Carolina Jubran <cjubran@nvidia.com>

Introduce support for specifying bandwidth proportions between traffic
classes (TC) in the devlink-rate API. This new option allows users to
allocate bandwidth across multiple traffic classes in a single command.

This feature provides a more granular control over traffic management,
especially for scenarios requiring Enhanced Transmission Selection.

Users can now define a specific bandwidth share for each traffic class,
such as allocating 20% for TC0 (TCP/UDP) and 80% for TC5 (RoCE).

Example:
DEV=pci/0000:08:00.0

$ devlink port function rate add $DEV/vfs_group tx_share 10Gbit \
tx_max 50Gbit tc-bw 0:20 1:0 2:0 3:0 4:0 5:80 6:0 7:0

$ devlink port function rate set $DEV/vfs_group \
tc-bw 0:20 1:0 2:0 3:0 4:0 5:20 6:60 7:0

Example usage with ynl:

./tools/net/ynl/cli.py --spec Documentation/netlink/specs/devlink.yaml \
--do rate-set --json '{
"bus-name": "pci",
"dev-name": "0000:08:00.0",
"port-index": 1,
"rate-tc-bws": [
{"rate-tc-index": 0, "rate-tc-bw": 50},
{"rate-tc-index": 1, "rate-tc-bw": 50},
{"rate-tc-index": 2, "rate-tc-bw": 0},
{"rate-tc-index": 3, "rate-tc-bw": 0},
{"rate-tc-index": 4, "rate-tc-bw": 0},
{"rate-tc-index": 5, "rate-tc-bw": 0},
{"rate-tc-index": 6, "rate-tc-bw": 0},
{"rate-tc-index": 7, "rate-tc-bw": 0}
]
}'

./tools/net/ynl/cli.py --spec Documentation/netlink/specs/devlink.yaml \
--do rate-get --json '{
"bus-name": "pci",
"dev-name": "0000:08:00.0",
"port-index": 1
}'

output for rate-get:
{'bus-name': 'pci',
'dev-name': '0000:08:00.0',
'port-index': 1,
'rate-tc-bws': [{'rate-tc-bw': 50, 'rate-tc-index': 0},
{'rate-tc-bw': 50, 'rate-tc-index': 1},
{'rate-tc-bw': 0, 'rate-tc-index': 2},
{'rate-tc-bw': 0, 'rate-tc-index': 3},
{'rate-tc-bw': 0, 'rate-tc-index': 4},
{'rate-tc-bw': 0, 'rate-tc-index': 5},
{'rate-tc-bw': 0, 'rate-tc-index': 6},
{'rate-tc-bw': 0, 'rate-tc-index': 7}],
'rate-tx-max': 0,
'rate-tx-priority': 0,
'rate-tx-share': 0,
'rate-tx-weight': 0,
'rate-type': 'leaf'}

Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
Documentation/netlink/specs/devlink.yaml | 36 ++++-
.../networking/devlink/devlink-port.rst | 7 +
include/net/devlink.h | 9 ++
include/uapi/linux/devlink.h | 4 +
net/devlink/netlink_gen.c | 16 ++-
net/devlink/netlink_gen.h | 2 +
net/devlink/rate.c | 127 ++++++++++++++++++
7 files changed, 196 insertions(+), 5 deletions(-)

diff --git a/Documentation/netlink/specs/devlink.yaml b/Documentation/netlink/specs/devlink.yaml
index 09fbb4c03fc8..3a6dd62b6684 100644
--- a/Documentation/netlink/specs/devlink.yaml
+++ b/Documentation/netlink/specs/devlink.yaml
@@ -202,6 +202,11 @@ definitions:
name: exception
-
name: control
+ -
+ name: devlink-rate-tc-index-max
+ header: net/devlink.h
+ type: const
+ value: 7

attribute-sets:
-
@@ -820,7 +825,26 @@ attribute-sets:
-
name: region-direct
type: flag
-
+ -
+ name: rate-tc-bws
+ type: nest
+ multi-attr: true
+ nested-attributes: dl-rate-tc-bws
+ -
+ name: rate-tc-index
+ type: u8
+ checks:
+ min: 0
+ max: devlink-rate-tc-index-max
+ -
+ name: rate-tc-bw
+ type: u32
+ doc: |
+ Specifies the bandwidth allocation for the Traffic Class as a
+ percentage.
+ checks:
+ min: 0
+ max: 100
-
name: dl-dev-stats
subset-of: devlink
@@ -1225,6 +1249,14 @@ attribute-sets:
-
name: flash
type: flag
+ -
+ name: dl-rate-tc-bws
+ subset-of: devlink
+ attributes:
+ -
+ name: rate-tc-index
+ -
+ name: rate-tc-bw

operations:
enum-model: directional
@@ -2149,6 +2181,7 @@ operations:
- rate-tx-priority
- rate-tx-weight
- rate-parent-node-name
+ - rate-tc-bws

-
name: rate-new
@@ -2169,6 +2202,7 @@ operations:
- rate-tx-priority
- rate-tx-weight
- rate-parent-node-name
+ - rate-tc-bws

-
name: rate-del
diff --git a/Documentation/networking/devlink/devlink-port.rst b/Documentation/networking/devlink/devlink-port.rst
index 9d22d41a7cd1..bc3b41ac2d51 100644
--- a/Documentation/networking/devlink/devlink-port.rst
+++ b/Documentation/networking/devlink/devlink-port.rst
@@ -418,6 +418,13 @@ API allows to configure following rate object's parameters:
to all node children limits. ``tx_max`` is an upper limit for children.
``tx_share`` is a total bandwidth distributed among children.

+``tc_bw``
+ Allow users to set the bandwidth allocation per traffic class on rate
+ objects. This enables fine-grained QoS configurations by assigning specific
+ bandwidth percentages to different traffic classes. When applied to a
+ non-leaf node, tc_bw determines how bandwidth is shared among its child
+ elements.
+
``tx_priority`` and ``tx_weight`` can be used simultaneously. In that case
nodes with the same priority form a WFQ subgroup in the sibling group
and arbitration among them is based on assigned weights.
diff --git a/include/net/devlink.h b/include/net/devlink.h
index b8783126c1ed..1b7fa11b5841 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -20,6 +20,7 @@
#include <uapi/linux/devlink.h>
#include <linux/xarray.h>
#include <linux/firmware.h>
+#include <linux/dcbnl.h>

struct devlink;
struct devlink_linecard;
@@ -99,6 +100,8 @@ struct devlink_port_attrs {
};
};

+#define DEVLINK_RATE_TC_INDEX_MAX (IEEE_8021QAZ_MAX_TCS - 1)
+
struct devlink_rate {
struct list_head list;
enum devlink_rate_type type;
@@ -118,6 +121,8 @@ struct devlink_rate {

u32 tx_priority;
u32 tx_weight;
+
+ u32 tc_bw[IEEE_8021QAZ_MAX_TCS];
};

struct devlink_port {
@@ -1482,6 +1487,8 @@ struct devlink_ops {
u32 tx_priority, struct netlink_ext_ack *extack);
int (*rate_leaf_tx_weight_set)(struct devlink_rate *devlink_rate, void *priv,
u32 tx_weight, struct netlink_ext_ack *extack);
+ int (*rate_leaf_tc_bw_set)(struct devlink_rate *devlink_rate, void *priv,
+ u32 *tc_bw, struct netlink_ext_ack *extack);
int (*rate_node_tx_share_set)(struct devlink_rate *devlink_rate, void *priv,
u64 tx_share, struct netlink_ext_ack *extack);
int (*rate_node_tx_max_set)(struct devlink_rate *devlink_rate, void *priv,
@@ -1490,6 +1497,8 @@ struct devlink_ops {
u32 tx_priority, struct netlink_ext_ack *extack);
int (*rate_node_tx_weight_set)(struct devlink_rate *devlink_rate, void *priv,
u32 tx_weight, struct netlink_ext_ack *extack);
+ int (*rate_node_tc_bw_set)(struct devlink_rate *devlink_rate, void *priv,
+ u32 *tc_bw, struct netlink_ext_ack *extack);
int (*rate_node_new)(struct devlink_rate *rate_node, void **priv,
struct netlink_ext_ack *extack);
int (*rate_node_del)(struct devlink_rate *rate_node, void *priv,
diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
index 9401aa343673..b3b538c67c34 100644
--- a/include/uapi/linux/devlink.h
+++ b/include/uapi/linux/devlink.h
@@ -614,6 +614,10 @@ enum devlink_attr {

DEVLINK_ATTR_REGION_DIRECT, /* flag */

+ DEVLINK_ATTR_RATE_TC_BWS, /* nested */
+ DEVLINK_ATTR_RATE_TC_INDEX, /* u8 */
+ DEVLINK_ATTR_RATE_TC_BW, /* u32 */
+
/* Add new attributes above here, update the spec in
* Documentation/netlink/specs/devlink.yaml and re-generate
* net/devlink/netlink_gen.c.
diff --git a/net/devlink/netlink_gen.c b/net/devlink/netlink_gen.c
index f9786d51f68f..186f31522af0 100644
--- a/net/devlink/netlink_gen.c
+++ b/net/devlink/netlink_gen.c
@@ -9,6 +9,7 @@
#include "netlink_gen.h"

#include <uapi/linux/devlink.h>
+#include <net/devlink.h>

/* Common nested types */
const struct nla_policy devlink_dl_port_function_nl_policy[DEVLINK_PORT_FN_ATTR_CAPS + 1] = {
@@ -18,6 +19,11 @@ const struct nla_policy devlink_dl_port_function_nl_policy[DEVLINK_PORT_FN_ATTR_
[DEVLINK_PORT_FN_ATTR_CAPS] = NLA_POLICY_BITFIELD32(15),
};

+const struct nla_policy devlink_dl_rate_tc_bws_nl_policy[DEVLINK_ATTR_RATE_TC_BW + 1] = {
+ [DEVLINK_ATTR_RATE_TC_INDEX] = NLA_POLICY_RANGE(NLA_U8, 0, DEVLINK_RATE_TC_INDEX_MAX),
+ [DEVLINK_ATTR_RATE_TC_BW] = NLA_POLICY_RANGE(NLA_U32, 0, 100),
+};
+
const struct nla_policy devlink_dl_selftest_id_nl_policy[DEVLINK_ATTR_SELFTEST_ID_FLASH + 1] = {
[DEVLINK_ATTR_SELFTEST_ID_FLASH] = { .type = NLA_FLAG, },
};
@@ -496,7 +502,7 @@ static const struct nla_policy devlink_rate_get_dump_nl_policy[DEVLINK_ATTR_DEV_
};

/* DEVLINK_CMD_RATE_SET - do */
-static const struct nla_policy devlink_rate_set_nl_policy[DEVLINK_ATTR_RATE_TX_WEIGHT + 1] = {
+static const struct nla_policy devlink_rate_set_nl_policy[DEVLINK_ATTR_RATE_TC_BWS + 1] = {
[DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING, },
[DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING, },
[DEVLINK_ATTR_RATE_NODE_NAME] = { .type = NLA_NUL_STRING, },
@@ -505,10 +511,11 @@ static const struct nla_policy devlink_rate_set_nl_policy[DEVLINK_ATTR_RATE_TX_W
[DEVLINK_ATTR_RATE_TX_PRIORITY] = { .type = NLA_U32, },
[DEVLINK_ATTR_RATE_TX_WEIGHT] = { .type = NLA_U32, },
[DEVLINK_ATTR_RATE_PARENT_NODE_NAME] = { .type = NLA_NUL_STRING, },
+ [DEVLINK_ATTR_RATE_TC_BWS] = NLA_POLICY_NESTED(devlink_dl_rate_tc_bws_nl_policy),
};

/* DEVLINK_CMD_RATE_NEW - do */
-static const struct nla_policy devlink_rate_new_nl_policy[DEVLINK_ATTR_RATE_TX_WEIGHT + 1] = {
+static const struct nla_policy devlink_rate_new_nl_policy[DEVLINK_ATTR_RATE_TC_BWS + 1] = {
[DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING, },
[DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING, },
[DEVLINK_ATTR_RATE_NODE_NAME] = { .type = NLA_NUL_STRING, },
@@ -517,6 +524,7 @@ static const struct nla_policy devlink_rate_new_nl_policy[DEVLINK_ATTR_RATE_TX_W
[DEVLINK_ATTR_RATE_TX_PRIORITY] = { .type = NLA_U32, },
[DEVLINK_ATTR_RATE_TX_WEIGHT] = { .type = NLA_U32, },
[DEVLINK_ATTR_RATE_PARENT_NODE_NAME] = { .type = NLA_NUL_STRING, },
+ [DEVLINK_ATTR_RATE_TC_BWS] = NLA_POLICY_NESTED(devlink_dl_rate_tc_bws_nl_policy),
};

/* DEVLINK_CMD_RATE_DEL - do */
@@ -1164,7 +1172,7 @@ const struct genl_split_ops devlink_nl_ops[74] = {
.doit = devlink_nl_rate_set_doit,
.post_doit = devlink_nl_post_doit,
.policy = devlink_rate_set_nl_policy,
- .maxattr = DEVLINK_ATTR_RATE_TX_WEIGHT,
+ .maxattr = DEVLINK_ATTR_RATE_TC_BWS,
.flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
},
{
@@ -1174,7 +1182,7 @@ const struct genl_split_ops devlink_nl_ops[74] = {
.doit = devlink_nl_rate_new_doit,
.post_doit = devlink_nl_post_doit,
.policy = devlink_rate_new_nl_policy,
- .maxattr = DEVLINK_ATTR_RATE_TX_WEIGHT,
+ .maxattr = DEVLINK_ATTR_RATE_TC_BWS,
.flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
},
{
diff --git a/net/devlink/netlink_gen.h b/net/devlink/netlink_gen.h
index 8f2bd50ddf5e..e3558cf89be4 100644
--- a/net/devlink/netlink_gen.h
+++ b/net/devlink/netlink_gen.h
@@ -10,9 +10,11 @@
#include <net/genetlink.h>

#include <uapi/linux/devlink.h>
+#include <net/devlink.h>

/* Common nested types */
extern const struct nla_policy devlink_dl_port_function_nl_policy[DEVLINK_PORT_FN_ATTR_CAPS + 1];
+extern const struct nla_policy devlink_dl_rate_tc_bws_nl_policy[DEVLINK_ATTR_RATE_TC_BW + 1];
extern const struct nla_policy devlink_dl_selftest_id_nl_policy[DEVLINK_ATTR_SELFTEST_ID_FLASH + 1];

/* Ops table for devlink */
diff --git a/net/devlink/rate.c b/net/devlink/rate.c
index 8828ffaf6cbc..3a046e929594 100644
--- a/net/devlink/rate.c
+++ b/net/devlink/rate.c
@@ -80,6 +80,29 @@ devlink_rate_get_from_info(struct devlink *devlink, struct genl_info *info)
return ERR_PTR(-EINVAL);
}

+static int devlink_rate_put_tc_bws(struct sk_buff *msg, u32 *tc_bw)
+{
+ struct nlattr *nla_tc_bw;
+ int i;
+
+ for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++) {
+ nla_tc_bw = nla_nest_start(msg, DEVLINK_ATTR_RATE_TC_BWS);
+ if (!nla_tc_bw)
+ return -EMSGSIZE;
+
+ if (nla_put_u8(msg, DEVLINK_ATTR_RATE_TC_INDEX, i) ||
+ nla_put_u32(msg, DEVLINK_ATTR_RATE_TC_BW, tc_bw[i]))
+ goto nla_put_failure;
+
+ nla_nest_end(msg, nla_tc_bw);
+ }
+ return 0;
+
+nla_put_failure:
+ nla_nest_cancel(msg, nla_tc_bw);
+ return -EMSGSIZE;
+}
+
static int devlink_nl_rate_fill(struct sk_buff *msg,
struct devlink_rate *devlink_rate,
enum devlink_command cmd, u32 portid, u32 seq,
@@ -129,6 +152,9 @@ static int devlink_nl_rate_fill(struct sk_buff *msg,
devlink_rate->parent->name))
goto nla_put_failure;

+ if (devlink_rate_put_tc_bws(msg, devlink_rate->tc_bw))
+ goto nla_put_failure;
+
genlmsg_end(msg, hdr);
return 0;

@@ -316,6 +342,89 @@ devlink_nl_rate_parent_node_set(struct devlink_rate *devlink_rate,
return 0;
}

+static int devlink_nl_rate_tc_bw_parse(struct nlattr *parent_nest, u32 *tc_bw,
+ unsigned long *bitmap, struct netlink_ext_ack *extack)
+{
+ struct nlattr *tb[DEVLINK_ATTR_MAX + 1];
+ u8 tc_index;
+
+ nla_parse_nested(tb, DEVLINK_ATTR_MAX, parent_nest, devlink_dl_rate_tc_bws_nl_policy,
+ extack);
+ if (!tb[DEVLINK_ATTR_RATE_TC_INDEX]) {
+ NL_SET_ERR_ATTR_MISS(extack, parent_nest, DEVLINK_ATTR_RATE_TC_INDEX);
+ return -EINVAL;
+ }
+
+ tc_index = nla_get_u8(tb[DEVLINK_ATTR_RATE_TC_INDEX]);
+
+ if (!tb[DEVLINK_ATTR_RATE_TC_BW]) {
+ NL_SET_ERR_ATTR_MISS(extack, parent_nest, DEVLINK_ATTR_RATE_TC_BW);
+ return -EINVAL;
+ }
+
+ if (test_and_set_bit(tc_index, bitmap)) {
+ NL_SET_ERR_MSG_FMT(extack, "Duplicate traffic class index specified (%u)",
+ tc_index);
+ return -EINVAL;
+ }
+
+ tc_bw[tc_index] = nla_get_u32(tb[DEVLINK_ATTR_RATE_TC_BW]);
+
+ return 0;
+}
+
+static int devlink_nl_rate_tc_bw_set(struct devlink_rate *devlink_rate,
+ struct genl_info *info)
+{
+ DECLARE_BITMAP(bitmap, IEEE_8021QAZ_MAX_TCS) = {};
+ struct devlink *devlink = devlink_rate->devlink;
+ const struct devlink_ops *ops = devlink->ops;
+ int rem, err = -EOPNOTSUPP, i, total = 0;
+ u32 tc_bw[IEEE_8021QAZ_MAX_TCS] = {};
+ struct nlattr *attr;
+
+ nla_for_each_attr(attr, genlmsg_data(info->genlhdr),
+ genlmsg_len(info->genlhdr), rem) {
+ if (nla_type(attr) == DEVLINK_ATTR_RATE_TC_BWS) {
+ err = devlink_nl_rate_tc_bw_parse(attr, tc_bw, bitmap, info->extack);
+ if (err)
+ return err;
+ }
+ }
+
+ for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++) {
+ if (!test_bit(i, bitmap)) {
+ NL_SET_ERR_MSG_FMT(info->extack,
+ "Bandwidth values must be specified for all %u traffic classes",
+ IEEE_8021QAZ_MAX_TCS);
+ return -EINVAL;
+ }
+
+ total += tc_bw[i];
+ }
+
+ if (total && total != 100) {
+ NL_SET_ERR_MSG_FMT(info->extack,
+ "Sum of all traffic class bandwidth share values must be 100, got %u",
+ total);
+ return -EINVAL;
+ }
+
+ if (devlink_rate_is_leaf(devlink_rate))
+ err = ops->rate_leaf_tc_bw_set(devlink_rate, devlink_rate->priv, tc_bw,
+ info->extack);
+ else if (devlink_rate_is_node(devlink_rate))
+ err = ops->rate_node_tc_bw_set(devlink_rate, devlink_rate->priv, tc_bw,
+ info->extack);
+
+ if (err)
+ return err;
+
+ memcpy(devlink_rate->tc_bw, tc_bw, sizeof(tc_bw));
+
+ return 0;
+}
+
static int devlink_nl_rate_set(struct devlink_rate *devlink_rate,
const struct devlink_ops *ops,
struct genl_info *info)
@@ -388,6 +497,12 @@ static int devlink_nl_rate_set(struct devlink_rate *devlink_rate,
return err;
}

+ if (attrs[DEVLINK_ATTR_RATE_TC_BWS]) {
+ err = devlink_nl_rate_tc_bw_set(devlink_rate, info);
+ if (err)
+ return err;
+ }
+
return 0;
}

@@ -423,6 +538,12 @@ static bool devlink_rate_set_ops_supported(const struct devlink_ops *ops,
"TX weight set isn't supported for the leafs");
return false;
}
+ if (attrs[DEVLINK_ATTR_RATE_TC_BWS] && !ops->rate_leaf_tc_bw_set) {
+ NL_SET_ERR_MSG_ATTR(info->extack,
+ attrs[DEVLINK_ATTR_RATE_TC_BWS],
+ "TC bandwidth set isn't supported for the leafs");
+ return false;
+ }
} else if (type == DEVLINK_RATE_TYPE_NODE) {
if (attrs[DEVLINK_ATTR_RATE_TX_SHARE] && !ops->rate_node_tx_share_set) {
NL_SET_ERR_MSG(info->extack, "TX share set isn't supported for the nodes");
@@ -449,6 +570,12 @@ static bool devlink_rate_set_ops_supported(const struct devlink_ops *ops,
"TX weight set isn't supported for the nodes");
return false;
}
+ if (attrs[DEVLINK_ATTR_RATE_TC_BWS] && !ops->rate_node_tc_bw_set) {
+ NL_SET_ERR_MSG_ATTR(info->extack,
+ attrs[DEVLINK_ATTR_RATE_TC_BWS],
+ "TC bandwidth set isn't supported for the nodes");
+ return false;
+ }
} else {
WARN(1, "Unknown type of rate object");
return false;
--
2.45.0