[PATCH net-next v7 1/6] net: rtnetlink: add pacing_offload_horizon attribute to net_device
From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Date: 2026-08-31 21:32:28
Subsystem:
documentation, networking drivers, networking [general], tc subsystem, the rest, yaml netlink (ynl) · Maintainers:
Jonathan Corbet, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Jamal Hadi Salim, Jiri Pirko, Linus Torvalds, Donald Hunter
From: Willem de Bruijn <willemb@google.com>
The 'max_pacing_offload_horizon' field of 'struct net_device' represents
the maximum pacing offload horizon supported by the device.
Add a new field 'pacing_offload_horizon' to store the active pacing
offload horizon.
The new attribute is initialized to 0 (disabled) and can be set from
userspace via RTM_SETLINK up to dev->max_pacing_offload_horizon. This
new default off behavior does not cause regressions, as no driver yet
advertises max_pacing_offload_horizon.
The attribute is omitted from the newlink request spec, because the
value may need to be bound by a device maximum that first needs to be
negotiated with firmware, as is the case for the idpf driver in this
series.
Make both fields u32, to maintain net_device cacheline layout. This
expresses up to 4s of pacing offload, which is sufficient.
Update the YNL specification ('rt-link.yaml') to add the
'pacing-offload-horizon' attribute and include it in link-all-attrs.
Both fields can be read with
ynl --spec /usr/local/share/ynl/specs/rt-link.yaml \
--do getlink \
--json '{"ifname": "eth0"}' | grep pacing
And the active horizon set with
ynl --spec /usr/local/share/ynl/specs/rt-link.yaml \
--do setlink \
--json '{"ifname": "eth0", "pacing-offload-horizon": 50000000}'
Signed-off-by: Willem de Bruijn <willemb@google.com>
----
Changes
v6 -> v7
- commit-msg: update ynl invocation to installed version
v5 -> v6
- bring back fq_change update
- commit-msg: reword absense of RTM_NEWLINK -> omitted from newlink
---
Documentation/netlink/specs/rt-link.yaml | 6 ++++++
.../networking/net_cachelines/net_device.rst | 3 ++-
include/linux/netdevice.h | 4 +++-
include/uapi/linux/if_link.h | 1 +
net/core/rtnetlink.c | 21 +++++++++++++++++++
net/sched/sch_fq.c | 3 ++-
6 files changed, 35 insertions(+), 3 deletions(-)
diff --git a/Documentation/netlink/specs/rt-link.yaml b/Documentation/netlink/specs/rt-link.yaml
index b80c2ac3ac31..292878ba7e15 100644
--- a/Documentation/netlink/specs/rt-link.yaml
+++ b/Documentation/netlink/specs/rt-link.yaml@@ -1085,6 +1085,10 @@ attribute-sets: - name: tailroom type: u16 + - + name: pacing-offload-horizon + type: uint + doc: EDT offload horizon setting for the device (in nsec). - name: prop-list-link-attrs subset-of: link-attrs
@@ -2553,6 +2557,8 @@ operations: - devlink-port - gso-ipv4-max-size - gro-ipv4-max-size + - max-pacing-offload-horizon + - pacing-offload-horizon dump: request: value: 18
diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst
index 512f6d6fa3d8..90e257e815b1 100644
--- a/Documentation/networking/net_cachelines/net_device.rst
+++ b/Documentation/networking/net_cachelines/net_device.rst@@ -183,7 +183,8 @@ struct devlink_port* devlink_port struct dpll_pin* dpll_pin struct hlist_head page_pools struct dim_irq_moder* irq_moder -u64 max_pacing_offload_horizon +u32 max_pacing_offload_horizon +u32 pacing_offload_horizon struct_napi_config* napi_config unsigned_long gro_flush_timeout u32 napi_defer_hard_irqs
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 87cafc932e9e..82a74ad284a1 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h@@ -2139,6 +2139,7 @@ enum netdev_reg_state { * where the clock is recovered. * * @max_pacing_offload_horizon: max EDT offload horizon in nsec. + * @pacing_offload_horizon: EDT offload horizon setting in nsec. * @napi_config: An array of napi_config structures containing per-NAPI * settings. * @num_napi_configs: number of allocated NAPI config structs,
@@ -2561,7 +2562,8 @@ struct net_device { /** @irq_moder: dim parameters used if IS_ENABLED(CONFIG_DIMLIB). */ struct dim_irq_moder *irq_moder; - u64 max_pacing_offload_horizon; + u32 max_pacing_offload_horizon; + u32 pacing_offload_horizon; struct napi_config *napi_config; u32 num_napi_configs; u32 napi_defer_hard_irqs;
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 43cecca49f01..7c1d7754a670 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h@@ -381,6 +381,7 @@ enum { IFLA_NETNS_IMMUTABLE, IFLA_HEADROOM, IFLA_TAILROOM, + IFLA_PACING_OFFLOAD_HORIZON, __IFLA_MAX };
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 81c5a6104dea..eeaf953b397f 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c@@ -1396,6 +1396,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev, + rtnl_devlink_port_size(dev) + rtnl_dpll_pin_size() + nla_total_size(8) /* IFLA_MAX_PACING_OFFLOAD_HORIZON */ + + nla_total_size(8) /* IFLA_PACING_OFFLOAD_HORIZON */ + nla_total_size(2) /* IFLA_HEADROOM */ + nla_total_size(2) /* IFLA_TAILROOM */ + rtnl_dev_parent_size(dev)
@@ -2176,6 +2177,8 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, READ_ONCE(dev->tso_max_segs)) || nla_put_uint(skb, IFLA_MAX_PACING_OFFLOAD_HORIZON, READ_ONCE(dev->max_pacing_offload_horizon)) || + nla_put_uint(skb, IFLA_PACING_OFFLOAD_HORIZON, + READ_ONCE(dev->pacing_offload_horizon)) || #ifdef CONFIG_RPS nla_put_u32(skb, IFLA_NUM_RX_QUEUES, READ_ONCE(dev->num_rx_queues)) ||
@@ -2344,9 +2347,11 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = { [IFLA_ALLMULTI] = { .type = NLA_REJECT }, [IFLA_GSO_IPV4_MAX_SIZE] = NLA_POLICY_MIN(NLA_U32, MAX_TCP_HEADER + 1), [IFLA_GRO_IPV4_MAX_SIZE] = { .type = NLA_U32 }, + [IFLA_MAX_PACING_OFFLOAD_HORIZON] = { .type = NLA_REJECT }, [IFLA_NETNS_IMMUTABLE] = { .type = NLA_REJECT }, [IFLA_HEADROOM] = { .type = NLA_REJECT }, [IFLA_TAILROOM] = { .type = NLA_REJECT }, + [IFLA_PACING_OFFLOAD_HORIZON] = { .type = NLA_UINT }, }; static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
@@ -2820,6 +2825,13 @@ static int validate_linkmsg(struct net_device *dev, struct nlattr *tb[], return -EINVAL; } + if (tb[IFLA_PACING_OFFLOAD_HORIZON] && + nla_get_uint(tb[IFLA_PACING_OFFLOAD_HORIZON]) > + dev->max_pacing_offload_horizon) { + NL_SET_ERR_MSG(extack, "too big pacing_offload_horizon"); + return -EINVAL; + } + if (tb[IFLA_AF_SPEC]) { struct nlattr *af; int rem, err;
@@ -3337,6 +3349,15 @@ static int do_setlink(const struct sk_buff *skb, struct net_device *dev, } } + if (tb[IFLA_PACING_OFFLOAD_HORIZON]) { + u64 horizon = nla_get_uint(tb[IFLA_PACING_OFFLOAD_HORIZON]); + + if (dev->pacing_offload_horizon ^ horizon) { + WRITE_ONCE(dev->pacing_offload_horizon, horizon); + status |= DO_SETLINK_MODIFIED; + } + } + if (tb[IFLA_OPERSTATE]) set_operstate(dev, nla_get_u8(tb[IFLA_OPERSTATE]));
diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c
index 6144b5686f13..7cf7afda699f 100644
--- a/net/sched/sch_fq.c
+++ b/net/sched/sch_fq.c@@ -1183,7 +1183,8 @@ static int fq_change(struct Qdisc *sch, struct nlattr *opt, u64 offload_horizon = (u64)NSEC_PER_USEC * nla_get_u32(tb[TCA_FQ_OFFLOAD_HORIZON]); - if (offload_horizon <= qdisc_dev(sch)->max_pacing_offload_horizon) { + if (offload_horizon <= + READ_ONCE(qdisc_dev(sch)->pacing_offload_horizon)) { WRITE_ONCE(q->offload_horizon, offload_horizon); } else { NL_SET_ERR_MSG_MOD(extack, "invalid offload_horizon");
--
2.55.0.897.gb25b4bd76c-goog