2 * Copyright (c) 2016 Qualcomm Atheros, Inc
6 * Based on net/sched/sch_fq_codel.c
8 #ifndef __NET_SCHED_FQ_IMPL_H
9 #define __NET_SCHED_FQ_IMPL_H
13 /* functions that are embedded into includer */
15 static struct sk_buff *fq_flow_dequeue(struct fq *fq,
18 struct fq_tin *tin = flow->tin;
22 lockdep_assert_held(&fq->lock);
24 skb = __skb_dequeue(&flow->queue);
28 tin->backlog_bytes -= skb->len;
29 tin->backlog_packets--;
30 flow->backlog -= skb->len;
32 fq->memory_usage -= skb->truesize;
34 if (flow->backlog == 0) {
35 list_del_init(&flow->backlogchain);
39 list_for_each_entry_continue(i, &fq->backlogs, backlogchain)
40 if (i->backlog < flow->backlog)
43 list_move_tail(&flow->backlogchain,
50 static struct sk_buff *fq_tin_dequeue(struct fq *fq,
52 fq_tin_dequeue_t dequeue_func)
55 struct list_head *head;
58 lockdep_assert_held(&fq->lock);
61 head = &tin->new_flows;
62 if (list_empty(head)) {
63 head = &tin->old_flows;
68 flow = list_first_entry(head, struct fq_flow, flowchain);
70 if (flow->deficit <= 0) {
71 flow->deficit += fq->quantum;
72 list_move_tail(&flow->flowchain,
77 skb = dequeue_func(fq, tin, flow);
79 /* force a pass through old_flows to prevent starvation */
80 if ((head == &tin->new_flows) &&
81 !list_empty(&tin->old_flows)) {
82 list_move_tail(&flow->flowchain, &tin->old_flows);
84 list_del_init(&flow->flowchain);
90 flow->deficit -= skb->len;
91 tin->tx_bytes += skb->len;
97 static struct fq_flow *fq_flow_classify(struct fq *fq,
100 fq_flow_get_default_t get_default_func)
102 struct fq_flow *flow;
106 lockdep_assert_held(&fq->lock);
108 hash = skb_get_hash_perturb(skb, fq->perturbation);
109 idx = reciprocal_scale(hash, fq->flows_cnt);
110 flow = &fq->flows[idx];
112 if (flow->tin && flow->tin != tin) {
113 flow = get_default_func(fq, tin, idx, skb);
124 static void fq_recalc_backlog(struct fq *fq,
126 struct fq_flow *flow)
130 if (list_empty(&flow->backlogchain))
131 list_add_tail(&flow->backlogchain, &fq->backlogs);
134 list_for_each_entry_continue_reverse(i, &fq->backlogs,
136 if (i->backlog > flow->backlog)
139 list_move(&flow->backlogchain, &i->backlogchain);
142 static void fq_tin_enqueue(struct fq *fq,
145 fq_skb_free_t free_func,
146 fq_flow_get_default_t get_default_func)
148 struct fq_flow *flow;
151 lockdep_assert_held(&fq->lock);
153 flow = fq_flow_classify(fq, tin, skb, get_default_func);
156 flow->backlog += skb->len;
157 tin->backlog_bytes += skb->len;
158 tin->backlog_packets++;
159 fq->memory_usage += skb->truesize;
162 fq_recalc_backlog(fq, tin, flow);
164 if (list_empty(&flow->flowchain)) {
165 flow->deficit = fq->quantum;
166 list_add_tail(&flow->flowchain,
170 __skb_queue_tail(&flow->queue, skb);
171 oom = (fq->memory_usage > fq->memory_limit);
172 while (fq->backlog > fq->limit || oom) {
173 flow = list_first_entry_or_null(&fq->backlogs,
179 skb = fq_flow_dequeue(fq, flow);
183 free_func(fq, flow->tin, flow, skb);
185 flow->tin->overlimit++;
189 oom = (fq->memory_usage > fq->memory_limit);
194 static void fq_flow_reset(struct fq *fq,
195 struct fq_flow *flow,
196 fq_skb_free_t free_func)
200 while ((skb = fq_flow_dequeue(fq, flow)))
201 free_func(fq, flow->tin, flow, skb);
203 if (!list_empty(&flow->flowchain))
204 list_del_init(&flow->flowchain);
206 if (!list_empty(&flow->backlogchain))
207 list_del_init(&flow->backlogchain);
211 WARN_ON_ONCE(flow->backlog);
214 static void fq_tin_reset(struct fq *fq,
216 fq_skb_free_t free_func)
218 struct list_head *head;
219 struct fq_flow *flow;
222 head = &tin->new_flows;
223 if (list_empty(head)) {
224 head = &tin->old_flows;
225 if (list_empty(head))
229 flow = list_first_entry(head, struct fq_flow, flowchain);
230 fq_flow_reset(fq, flow, free_func);
233 WARN_ON_ONCE(tin->backlog_bytes);
234 WARN_ON_ONCE(tin->backlog_packets);
237 static void fq_flow_init(struct fq_flow *flow)
239 INIT_LIST_HEAD(&flow->flowchain);
240 INIT_LIST_HEAD(&flow->backlogchain);
241 __skb_queue_head_init(&flow->queue);
244 static void fq_tin_init(struct fq_tin *tin)
246 INIT_LIST_HEAD(&tin->new_flows);
247 INIT_LIST_HEAD(&tin->old_flows);
250 static int fq_init(struct fq *fq, int flows_cnt)
254 memset(fq, 0, sizeof(fq[0]));
255 INIT_LIST_HEAD(&fq->backlogs);
256 spin_lock_init(&fq->lock);
257 fq->flows_cnt = max_t(u32, flows_cnt, 1);
258 fq->perturbation = prandom_u32();
261 fq->memory_limit = 16 << 20; /* 16 MBytes */
263 fq->flows = kcalloc(fq->flows_cnt, sizeof(fq->flows[0]), GFP_KERNEL);
267 for (i = 0; i < fq->flows_cnt; i++)
268 fq_flow_init(&fq->flows[i]);
273 static void fq_reset(struct fq *fq,
274 fq_skb_free_t free_func)
278 for (i = 0; i < fq->flows_cnt; i++)
279 fq_flow_reset(fq, &fq->flows[i], free_func);