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authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /net/sched/sch_plug.c
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Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
Pull networking updates from Jakub Kicinski: "Core: - Add dedicated kmem_cache for typical/small skb->head, avoid having to access struct page at kfree time, and improve memory use. - Introduce sysctl to set default RPS configuration for new netdevs. - Define Netlink protocol specification format which can be used to describe messages used by each family and auto-generate parsers. Add tools for generating kernel data structures and uAPI headers. - Expose all net/core sysctls inside netns. - Remove 4s sleep in netpoll if carrier is instantly detected on boot. - Add configurable limit of MDB entries per port, and port-vlan. - Continue populating drop reasons throughout the stack. - Retire a handful of legacy Qdiscs and classifiers. Protocols: - Support IPv4 big TCP (TSO frames larger than 64kB). - Add IP_LOCAL_PORT_RANGE socket option, to control local port range on socket by socket basis. - Track and report in procfs number of MPTCP sockets used. - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path manager. - IPv6: don't check net.ipv6.route.max_size and rely on garbage collection to free memory (similarly to IPv4). - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986). - ICMP: add per-rate limit counters. - Add support for user scanning requests in ieee802154. - Remove static WEP support. - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate reporting. - WiFi 7 EHT channel puncturing support (client & AP). BPF: - Add a rbtree data structure following the "next-gen data structure" precedent set by recently added linked list, that is, by using kfunc + kptr instead of adding a new BPF map type. - Expose XDP hints via kfuncs with initial support for RX hash and timestamp metadata. - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata. - Improve x86 JIT's codegen for PROBE_MEM runtime error checks. - Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers. - Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case. - Significantly reduce the search time for module symbols by livepatch and BPF. - Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals. - Add support for BPF trampoline on s390x and riscv64. - Add capability to export the XDP features supported by the NIC. - Add __bpf_kfunc tag for marking kernel functions as kfuncs. - Add cgroup.memory=nobpf kernel parameter option to disable BPF memory accounting for container environments. Netfilter: - Remove the CLUSTERIP target. It has been marked as obsolete for years, and we still have WARN splats wrt races of the out-of-band /proc interface installed by this target. - Add 'destroy' commands to nf_tables. They are identical to the existing 'delete' commands, but do not return an error if the referenced object (set, chain, rule...) did not exist. Driver API: - Improve cpumask_local_spread() locality to help NICs set the right IRQ affinity on AMD platforms. - Separate C22 and C45 MDIO bus transactions more clearly. - Introduce new DCB table to control DSCP rewrite on egress. - Support configuration of Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of shared medium Ethernet. - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing preemption of low priority frames by high priority frames. - Add support for controlling MACSec offload using netlink SET. - Rework devlink instance refcounts to allow registration and de-registration under the instance lock. Split the code into multiple files, drop some of the unnecessarily granular locks and factor out common parts of netlink operation handling. - Add TX frame aggregation parameters (for USB drivers). - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning messages with notifications for debug. - Allow offloading of UDP NEW connections via act_ct. - Add support for per action HW stats in TC. - Support hardware miss to TC action (continue processing in SW from a specific point in the action chain). - Warn if old Wireless Extension user space interface is used with modern cfg80211/mac80211 drivers. Do not support Wireless Extensions for Wi-Fi 7 devices at all. Everyone should switch to using nl80211 interface instead. - Improve the CAN bit timing configuration. Use extack to return error messages directly to user space, update the SJW handling, including the definition of a new default value that will benefit CAN-FD controllers, by increasing their oscillator tolerance. New hardware / drivers: - Ethernet: - nVidia BlueField-3 support (control traffic driver) - Ethernet support for imx93 SoCs - Motorcomm yt8531 gigabit Ethernet PHY - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA) - Microchip LAN8841 PHY (incl. cable diagnostics and PTP) - Amlogic gxl MDIO mux - WiFi: - RealTek RTL8188EU (rtl8xxxu) - Qualcomm Wi-Fi 7 devices (ath12k) - CAN: - Renesas R-Car V4H Drivers: - Bluetooth: - Set Per Platform Antenna Gain (PPAG) for Intel controllers. - Ethernet NICs: - Intel (1G, igc): - support TSN / Qbv / packet scheduling features of i226 model - Intel (100G, ice): - use GNSS subsystem instead of TTY - multi-buffer XDP support - extend support for GPIO pins to E823 devices - nVidia/Mellanox: - update the shared buffer configuration on PFC commands - implement PTP adjphase function for HW offset control - TC support for Geneve and GRE with VF tunnel offload - more efficient crypto key management method - multi-port eswitch support - Netronome/Corigine: - add DCB IEEE support - support IPsec offloading for NFP3800 - Freescale/NXP (enetc): - support XDP_REDIRECT for XDP non-linear buffers - improve reconfig, avoid link flap and waiting for idle - support MAC Merge layer - Other NICs: - sfc/ef100: add basic devlink support for ef100 - ionic: rx_push mode operation (writing descriptors via MMIO) - bnxt: use the auxiliary bus abstraction for RDMA - r8169: disable ASPM and reset bus in case of tx timeout - cpsw: support QSGMII mode for J721e CPSW9G - cpts: support pulse-per-second output - ngbe: add an mdio bus driver - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing - r8152: handle devices with FW with NCM support - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation - virtio-net: support multi buffer XDP - virtio/vsock: replace virtio_vsock_pkt with sk_buff - tsnep: XDP support - Ethernet high-speed switches: - nVidia/Mellanox (mlxsw): - add support for latency TLV (in FW control messages) - Microchip (sparx5): - separate explicit and implicit traffic forwarding rules, make the implicit rules always active - add support for egress DSCP rewrite - IS0 VCAP support (Ingress Classification) - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.) - ES2 VCAP support (Egress Access Control) - support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1) - Ethernet embedded switches: - Marvell (mv88e6xxx): - add MAB (port auth) offload support - enable PTP receive for mv88e6390 - NXP (ocelot): - support MAC Merge layer - support for the the vsc7512 internal copper phys - Microchip: - lan9303: convert to PHYLINK - lan966x: support TC flower filter statistics - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x - lan937x: support Credit Based Shaper configuration - ksz9477: support Energy Efficient Ethernet - other: - qca8k: convert to regmap read/write API, use bulk operations - rswitch: Improve TX timestamp accuracy - Intel WiFi (iwlwifi): - EHT (Wi-Fi 7) rate reporting - STEP equalizer support: transfer some STEP (connection to radio on platforms with integrated wifi) related parameters from the BIOS to the firmware. - Qualcomm 802.11ax WiFi (ath11k): - IPQ5018 support - Fine Timing Measurement (FTM) responder role support - channel 177 support - MediaTek WiFi (mt76): - per-PHY LED support - mt7996: EHT (Wi-Fi 7) support - Wireless Ethernet Dispatch (WED) reset support - switch to using page pool allocator - RealTek WiFi (rtw89): - support new version of Bluetooth co-existance - Mobile: - rmnet: support TX aggregation" * tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits) page_pool: add a comment explaining the fragment counter usage net: ethtool: fix __ethtool_dev_mm_supported() implementation ethtool: pse-pd: Fix double word in comments xsk: add linux/vmalloc.h to xsk.c sefltests: netdevsim: wait for devlink instance after netns removal selftest: fib_tests: Always cleanup before exit net/mlx5e: Align IPsec ASO result memory to be as required by hardware net/mlx5e: TC, Set CT miss to the specific ct action instance net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG net/mlx5: Refactor tc miss handling to a single function net/mlx5: Kconfig: Make tc offload depend on tc skb extension net/sched: flower: Support hardware miss to tc action net/sched: flower: Move filter handle initialization earlier net/sched: cls_api: Support hardware miss to tc action net/sched: Rename user cookie and act cookie sfc: fix builds without CONFIG_RTC_LIB sfc: clean up some inconsistent indentings net/mlx4_en: Introduce flexible array to silence overflow warning net: lan966x: Fix possible deadlock inside PTP net/ulp: Remove redundant ->clone() test in inet_clone_ulp(). ...
Diffstat (limited to '')
-rw-r--r--net/sched/sch_plug.c228
1 files changed, 228 insertions, 0 deletions
diff --git a/net/sched/sch_plug.c b/net/sched/sch_plug.c
new file mode 100644
index 000000000..ea8c4a717
--- /dev/null
+++ b/net/sched/sch_plug.c
@@ -0,0 +1,228 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * sch_plug.c Queue traffic until an explicit release command
+ *
+ * There are two ways to use this qdisc:
+ * 1. A simple "instantaneous" plug/unplug operation, by issuing an alternating
+ * sequence of TCQ_PLUG_BUFFER & TCQ_PLUG_RELEASE_INDEFINITE commands.
+ *
+ * 2. For network output buffering (a.k.a output commit) functionality.
+ * Output commit property is commonly used by applications using checkpoint
+ * based fault-tolerance to ensure that the checkpoint from which a system
+ * is being restored is consistent w.r.t outside world.
+ *
+ * Consider for e.g. Remus - a Virtual Machine checkpointing system,
+ * wherein a VM is checkpointed, say every 50ms. The checkpoint is replicated
+ * asynchronously to the backup host, while the VM continues executing the
+ * next epoch speculatively.
+ *
+ * The following is a typical sequence of output buffer operations:
+ * 1.At epoch i, start_buffer(i)
+ * 2. At end of epoch i (i.e. after 50ms):
+ * 2.1 Stop VM and take checkpoint(i).
+ * 2.2 start_buffer(i+1) and Resume VM
+ * 3. While speculatively executing epoch(i+1), asynchronously replicate
+ * checkpoint(i) to backup host.
+ * 4. When checkpoint_ack(i) is received from backup, release_buffer(i)
+ * Thus, this Qdisc would receive the following sequence of commands:
+ * TCQ_PLUG_BUFFER (epoch i)
+ * .. TCQ_PLUG_BUFFER (epoch i+1)
+ * ....TCQ_PLUG_RELEASE_ONE (epoch i)
+ * ......TCQ_PLUG_BUFFER (epoch i+2)
+ * ........
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/pkt_sched.h>
+
+/*
+ * State of the queue, when used for network output buffering:
+ *
+ * plug(i+1) plug(i) head
+ * ------------------+--------------------+---------------->
+ * | |
+ * | |
+ * pkts_current_epoch| pkts_last_epoch |pkts_to_release
+ * ----------------->|<--------+--------->|+--------------->
+ * v v
+ *
+ */
+
+struct plug_sched_data {
+ /* If true, the dequeue function releases all packets
+ * from head to end of the queue. The queue turns into
+ * a pass-through queue for newly arriving packets.
+ */
+ bool unplug_indefinite;
+
+ bool throttled;
+
+ /* Queue Limit in bytes */
+ u32 limit;
+
+ /* Number of packets (output) from the current speculatively
+ * executing epoch.
+ */
+ u32 pkts_current_epoch;
+
+ /* Number of packets corresponding to the recently finished
+ * epoch. These will be released when we receive a
+ * TCQ_PLUG_RELEASE_ONE command. This command is typically
+ * issued after committing a checkpoint at the target.
+ */
+ u32 pkts_last_epoch;
+
+ /*
+ * Number of packets from the head of the queue, that can
+ * be released (committed checkpoint).
+ */
+ u32 pkts_to_release;
+};
+
+static int plug_enqueue(struct sk_buff *skb, struct Qdisc *sch,
+ struct sk_buff **to_free)
+{
+ struct plug_sched_data *q = qdisc_priv(sch);
+
+ if (likely(sch->qstats.backlog + skb->len <= q->limit)) {
+ if (!q->unplug_indefinite)
+ q->pkts_current_epoch++;
+ return qdisc_enqueue_tail(skb, sch);
+ }
+
+ return qdisc_drop(skb, sch, to_free);
+}
+
+static struct sk_buff *plug_dequeue(struct Qdisc *sch)
+{
+ struct plug_sched_data *q = qdisc_priv(sch);
+
+ if (q->throttled)
+ return NULL;
+
+ if (!q->unplug_indefinite) {
+ if (!q->pkts_to_release) {
+ /* No more packets to dequeue. Block the queue
+ * and wait for the next release command.
+ */
+ q->throttled = true;
+ return NULL;
+ }
+ q->pkts_to_release--;
+ }
+
+ return qdisc_dequeue_head(sch);
+}
+
+static int plug_init(struct Qdisc *sch, struct nlattr *opt,
+ struct netlink_ext_ack *extack)
+{
+ struct plug_sched_data *q = qdisc_priv(sch);
+
+ q->pkts_current_epoch = 0;
+ q->pkts_last_epoch = 0;
+ q->pkts_to_release = 0;
+ q->unplug_indefinite = false;
+
+ if (opt == NULL) {
+ q->limit = qdisc_dev(sch)->tx_queue_len
+ * psched_mtu(qdisc_dev(sch));
+ } else {
+ struct tc_plug_qopt *ctl = nla_data(opt);
+
+ if (nla_len(opt) < sizeof(*ctl))
+ return -EINVAL;
+
+ q->limit = ctl->limit;
+ }
+
+ q->throttled = true;
+ return 0;
+}
+
+/* Receives 4 types of messages:
+ * TCQ_PLUG_BUFFER: Inset a plug into the queue and
+ * buffer any incoming packets
+ * TCQ_PLUG_RELEASE_ONE: Dequeue packets from queue head
+ * to beginning of the next plug.
+ * TCQ_PLUG_RELEASE_INDEFINITE: Dequeue all packets from queue.
+ * Stop buffering packets until the next TCQ_PLUG_BUFFER
+ * command is received (just act as a pass-thru queue).
+ * TCQ_PLUG_LIMIT: Increase/decrease queue size
+ */
+static int plug_change(struct Qdisc *sch, struct nlattr *opt,
+ struct netlink_ext_ack *extack)
+{
+ struct plug_sched_data *q = qdisc_priv(sch);
+ struct tc_plug_qopt *msg;
+
+ msg = nla_data(opt);
+ if (nla_len(opt) < sizeof(*msg))
+ return -EINVAL;
+
+ switch (msg->action) {
+ case TCQ_PLUG_BUFFER:
+ /* Save size of the current buffer */
+ q->pkts_last_epoch = q->pkts_current_epoch;
+ q->pkts_current_epoch = 0;
+ if (q->unplug_indefinite)
+ q->throttled = true;
+ q->unplug_indefinite = false;
+ break;
+ case TCQ_PLUG_RELEASE_ONE:
+ /* Add packets from the last complete buffer to the
+ * packets to be released set.
+ */
+ q->pkts_to_release += q->pkts_last_epoch;
+ q->pkts_last_epoch = 0;
+ q->throttled = false;
+ netif_schedule_queue(sch->dev_queue);
+ break;
+ case TCQ_PLUG_RELEASE_INDEFINITE:
+ q->unplug_indefinite = true;
+ q->pkts_to_release = 0;
+ q->pkts_last_epoch = 0;
+ q->pkts_current_epoch = 0;
+ q->throttled = false;
+ netif_schedule_queue(sch->dev_queue);
+ break;
+ case TCQ_PLUG_LIMIT:
+ /* Limit is supplied in bytes */
+ q->limit = msg->limit;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static struct Qdisc_ops plug_qdisc_ops __read_mostly = {
+ .id = "plug",
+ .priv_size = sizeof(struct plug_sched_data),
+ .enqueue = plug_enqueue,
+ .dequeue = plug_dequeue,
+ .peek = qdisc_peek_head,
+ .init = plug_init,
+ .change = plug_change,
+ .reset = qdisc_reset_queue,
+ .owner = THIS_MODULE,
+};
+
+static int __init plug_module_init(void)
+{
+ return register_qdisc(&plug_qdisc_ops);
+}
+
+static void __exit plug_module_exit(void)
+{
+ unregister_qdisc(&plug_qdisc_ops);
+}
+module_init(plug_module_init)
+module_exit(plug_module_exit)
+MODULE_LICENSE("GPL");