xref: /kernel/linux/linux-5.10/include/net/fq.h (revision 8c2ecf20)
1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (c) 2016 Qualcomm Atheros, Inc
4 *
5 * Based on net/sched/sch_fq_codel.c
6 */
7#ifndef __NET_SCHED_FQ_H
8#define __NET_SCHED_FQ_H
9
10struct fq_tin;
11
12/**
13 * struct fq_flow - per traffic flow queue
14 *
15 * @tin: owner of this flow. Used to manage collisions, i.e. when a packet
16 *	hashes to an index which points to a flow that is already owned by a
17 *	different tin the packet is destined to. In such case the implementer
18 *	must provide a fallback flow
19 * @flowchain: can be linked to fq_tin's new_flows or old_flows. Used for DRR++
20 *	(deficit round robin) based round robin queuing similar to the one
21 *	found in net/sched/sch_fq_codel.c
22 * @backlogchain: can be linked to other fq_flow and fq. Used to keep track of
23 *	fat flows and efficient head-dropping if packet limit is reached
24 * @queue: sk_buff queue to hold packets
25 * @backlog: number of bytes pending in the queue. The number of packets can be
26 *	found in @queue.qlen
27 * @deficit: used for DRR++
28 */
29struct fq_flow {
30	struct fq_tin *tin;
31	struct list_head flowchain;
32	struct list_head backlogchain;
33	struct sk_buff_head queue;
34	u32 backlog;
35	int deficit;
36};
37
38/**
39 * struct fq_tin - a logical container of fq_flows
40 *
41 * Used to group fq_flows into a logical aggregate. DRR++ scheme is used to
42 * pull interleaved packets out of the associated flows.
43 *
44 * @new_flows: linked list of fq_flow
45 * @old_flows: linked list of fq_flow
46 */
47struct fq_tin {
48	struct list_head new_flows;
49	struct list_head old_flows;
50	u32 backlog_bytes;
51	u32 backlog_packets;
52	u32 overlimit;
53	u32 collisions;
54	u32 flows;
55	u32 tx_bytes;
56	u32 tx_packets;
57};
58
59/**
60 * struct fq - main container for fair queuing purposes
61 *
62 * @backlogs: linked to fq_flows. Used to maintain fat flows for efficient
63 *	head-dropping when @backlog reaches @limit
64 * @limit: max number of packets that can be queued across all flows
65 * @backlog: number of packets queued across all flows
66 */
67struct fq {
68	struct fq_flow *flows;
69	struct list_head backlogs;
70	spinlock_t lock;
71	u32 flows_cnt;
72	u32 limit;
73	u32 memory_limit;
74	u32 memory_usage;
75	u32 quantum;
76	u32 backlog;
77	u32 overlimit;
78	u32 overmemory;
79	u32 collisions;
80};
81
82typedef struct sk_buff *fq_tin_dequeue_t(struct fq *,
83					 struct fq_tin *,
84					 struct fq_flow *flow);
85
86typedef void fq_skb_free_t(struct fq *,
87			   struct fq_tin *,
88			   struct fq_flow *,
89			   struct sk_buff *);
90
91/* Return %true to filter (drop) the frame. */
92typedef bool fq_skb_filter_t(struct fq *,
93			     struct fq_tin *,
94			     struct fq_flow *,
95			     struct sk_buff *,
96			     void *);
97
98typedef struct fq_flow *fq_flow_get_default_t(struct fq *,
99					      struct fq_tin *,
100					      int idx,
101					      struct sk_buff *);
102
103#endif
104