From f858cc9eed5b05cbe38d7ffd2787c21e3718eb7d Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 3 Oct 2024 12:12:18 +0000 Subject: [PATCH] net: add IFLA_MAX_PACING_OFFLOAD_HORIZON device attribute Some network devices have the ability to offload EDT (Earliest Departure Time) which is the model used for TCP pacing and FQ packet scheduler. Some of them implement the timing wheel mechanism described in https://saeed.github.io/files/carousel-sigcomm17.pdf with an associated 'timing wheel horizon'. This patch adds dev->max_pacing_offload_horizon expressing this timing wheel horizon in nsec units. This is a read-only attribute. Unless a driver sets it, dev->max_pacing_offload_horizon is zero. v2: addressed Jakub feedback ( https://lore.kernel.org/netdev/20240930152304.472767-2-edumazet@google.com/T/#mf6294d714c41cc459962154cc2580ce3c9693663 ) v3: added yaml doc (also per Jakub feedback) Signed-off-by: Eric Dumazet Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20241003121219.2396589-2-edumazet@google.com Signed-off-by: Jakub Kicinski --- Documentation/netlink/specs/rt_link.yaml | 4 ++++ Documentation/networking/net_cachelines/net_device.rst | 1 + include/linux/netdevice.h | 4 ++++ include/uapi/linux/if_link.h | 1 + net/core/rtnetlink.c | 4 ++++ tools/include/uapi/linux/if_link.h | 1 + 6 files changed, 15 insertions(+) diff --git a/Documentation/netlink/specs/rt_link.yaml b/Documentation/netlink/specs/rt_link.yaml index 0c4d5d40cae9..d7131a1afadf 100644 --- a/Documentation/netlink/specs/rt_link.yaml +++ b/Documentation/netlink/specs/rt_link.yaml @@ -1137,6 +1137,10 @@ attribute-sets: name: dpll-pin type: nest nested-attributes: link-dpll-pin-attrs + - + name: max-pacing-offload-horizon + type: uint + doc: EDT offload horizon supported by the device (in nsec). - name: af-spec-attrs attributes: diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst index 22b07c814f4a..49f03cb78c6e 100644 --- a/Documentation/networking/net_cachelines/net_device.rst +++ b/Documentation/networking/net_cachelines/net_device.rst @@ -183,3 +183,4 @@ 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 diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 4d20c776a4ff..49a7e7db0883 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2009,6 +2009,8 @@ enum netdev_reg_state { * @dpll_pin: Pointer to the SyncE source pin of a DPLL subsystem, * where the clock is recovered. * + * @max_pacing_offload_horizon: max EDT offload horizon in nsec. + * * FIXME: cleanup struct net_device such that network protocol info * moves out. */ @@ -2399,6 +2401,8 @@ struct net_device { /** @irq_moder: dim parameters used if IS_ENABLED(CONFIG_DIMLIB). */ struct dim_irq_moder *irq_moder; + u64 max_pacing_offload_horizon; + u8 priv[] ____cacheline_aligned __counted_by(priv_len); } ____cacheline_aligned; diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h index 6dc258993b17..506ba9c80e83 100644 --- a/include/uapi/linux/if_link.h +++ b/include/uapi/linux/if_link.h @@ -377,6 +377,7 @@ enum { IFLA_GSO_IPV4_MAX_SIZE, IFLA_GRO_IPV4_MAX_SIZE, IFLA_DPLL_PIN, + IFLA_MAX_PACING_OFFLOAD_HORIZON, __IFLA_MAX }; diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index f0a520987085..682d8d3127db 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -1118,6 +1118,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev, + nla_total_size(MAX_ADDR_LEN) /* IFLA_PERM_ADDRESS */ + rtnl_devlink_port_size(dev) + rtnl_dpll_pin_size(dev) + + nla_total_size(8) /* IFLA_MAX_PACING_OFFLOAD_HORIZON */ + 0; } @@ -1867,6 +1868,8 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, READ_ONCE(dev->tso_max_size)) || nla_put_u32(skb, IFLA_TSO_MAX_SEGS, READ_ONCE(dev->tso_max_segs)) || + nla_put_uint(skb, IFLA_MAX_PACING_OFFLOAD_HORIZON, + READ_ONCE(dev->max_pacing_offload_horizon)) || #ifdef CONFIG_RPS nla_put_u32(skb, IFLA_NUM_RX_QUEUES, READ_ONCE(dev->num_rx_queues)) || @@ -1975,6 +1978,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, } static const struct nla_policy ifla_policy[IFLA_MAX+1] = { + [IFLA_UNSPEC] = { .strict_start_type = IFLA_DPLL_PIN }, [IFLA_IFNAME] = { .type = NLA_STRING, .len = IFNAMSIZ-1 }, [IFLA_ADDRESS] = { .type = NLA_BINARY, .len = MAX_ADDR_LEN }, [IFLA_BROADCAST] = { .type = NLA_BINARY, .len = MAX_ADDR_LEN }, diff --git a/tools/include/uapi/linux/if_link.h b/tools/include/uapi/linux/if_link.h index f0d71b2a3f1e..96ec2b01e725 100644 --- a/tools/include/uapi/linux/if_link.h +++ b/tools/include/uapi/linux/if_link.h @@ -377,6 +377,7 @@ enum { IFLA_GSO_IPV4_MAX_SIZE, IFLA_GRO_IPV4_MAX_SIZE, IFLA_DPLL_PIN, + IFLA_MAX_PACING_OFFLOAD_HORIZON, __IFLA_MAX };