xref: /openbmc/linux/include/net/fq.h (revision b830f94f)
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 
10 struct 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  */
29 struct 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  */
47 struct 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  */
67 struct fq {
68 	struct fq_flow *flows;
69 	struct list_head backlogs;
70 	spinlock_t lock;
71 	u32 flows_cnt;
72 	u32 perturbation;
73 	u32 limit;
74 	u32 memory_limit;
75 	u32 memory_usage;
76 	u32 quantum;
77 	u32 backlog;
78 	u32 overlimit;
79 	u32 overmemory;
80 	u32 collisions;
81 };
82 
83 typedef struct sk_buff *fq_tin_dequeue_t(struct fq *,
84 					 struct fq_tin *,
85 					 struct fq_flow *flow);
86 
87 typedef void fq_skb_free_t(struct fq *,
88 			   struct fq_tin *,
89 			   struct fq_flow *,
90 			   struct sk_buff *);
91 
92 /* Return %true to filter (drop) the frame. */
93 typedef bool fq_skb_filter_t(struct fq *,
94 			     struct fq_tin *,
95 			     struct fq_flow *,
96 			     struct sk_buff *,
97 			     void *);
98 
99 typedef struct fq_flow *fq_flow_get_default_t(struct fq *,
100 					      struct fq_tin *,
101 					      int idx,
102 					      struct sk_buff *);
103 
104 #endif
105