1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * net/sched/sch_fq.c Fair Queue Packet Scheduler (per flow pacing)
4 *
5 * Copyright (C) 2013-2023 Eric Dumazet <edumazet@google.com>
6 *
7 * Meant to be mostly used for locally generated traffic :
8 * Fast classification depends on skb->sk being set before reaching us.
9 * If not, (router workload), we use rxhash as fallback, with 32 bits wide hash.
10 * All packets belonging to a socket are considered as a 'flow'.
11 *
12 * Flows are dynamically allocated and stored in a hash table of RB trees
13 * They are also part of one Round Robin 'queues' (new or old flows)
14 *
15 * Burst avoidance (aka pacing) capability :
16 *
17 * Transport (eg TCP) can set in sk->sk_pacing_rate a rate, enqueue a
18 * bunch of packets, and this packet scheduler adds delay between
19 * packets to respect rate limitation.
20 *
21 * enqueue() :
22 * - lookup one RB tree (out of 1024 or more) to find the flow.
23 * If non existent flow, create it, add it to the tree.
24 * Add skb to the per flow list of skb (fifo).
25 * - Use a special fifo for high prio packets
26 *
27 * dequeue() : serves flows in Round Robin
28 * Note : When a flow becomes empty, we do not immediately remove it from
29 * rb trees, for performance reasons (its expected to send additional packets,
30 * or SLAB cache will reuse socket for another flow)
31 */
32
33 #include <linux/module.h>
34 #include <linux/types.h>
35 #include <linux/kernel.h>
36 #include <linux/jiffies.h>
37 #include <linux/string.h>
38 #include <linux/in.h>
39 #include <linux/errno.h>
40 #include <linux/init.h>
41 #include <linux/skbuff.h>
42 #include <linux/slab.h>
43 #include <linux/rbtree.h>
44 #include <linux/hash.h>
45 #include <linux/prefetch.h>
46 #include <linux/vmalloc.h>
47 #include <net/netlink.h>
48 #include <net/pkt_sched.h>
49 #include <net/sock.h>
50 #include <net/tcp_states.h>
51 #include <net/tcp.h>
52
53 struct fq_skb_cb {
54 u64 time_to_send;
55 u8 band;
56 };
57
fq_skb_cb(struct sk_buff * skb)58 static inline struct fq_skb_cb *fq_skb_cb(struct sk_buff *skb)
59 {
60 qdisc_cb_private_validate(skb, sizeof(struct fq_skb_cb));
61 return (struct fq_skb_cb *)qdisc_skb_cb(skb)->data;
62 }
63
64 /*
65 * Per flow structure, dynamically allocated.
66 * If packets have monotically increasing time_to_send, they are placed in O(1)
67 * in linear list (head,tail), otherwise are placed in a rbtree (t_root).
68 */
69 struct fq_flow {
70 /* First cache line : used in fq_gc(), fq_enqueue(), fq_dequeue() */
71 struct rb_root t_root;
72 struct sk_buff *head; /* list of skbs for this flow : first skb */
73 union {
74 struct sk_buff *tail; /* last skb in the list */
75 unsigned long age; /* (jiffies | 1UL) when flow was emptied, for gc */
76 };
77 union {
78 struct rb_node fq_node; /* anchor in fq_root[] trees */
79 /* Following field is only used for q->internal,
80 * because q->internal is not hashed in fq_root[]
81 */
82 u64 stat_fastpath_packets;
83 };
84 struct sock *sk;
85 u32 socket_hash; /* sk_hash */
86 int qlen; /* number of packets in flow queue */
87
88 /* Second cache line */
89 int credit;
90 int band;
91 struct fq_flow *next; /* next pointer in RR lists */
92
93 struct rb_node rate_node; /* anchor in q->delayed tree */
94 u64 time_next_packet;
95 };
96
97 struct fq_flow_head {
98 struct fq_flow *first;
99 struct fq_flow *last;
100 };
101
102 struct fq_perband_flows {
103 struct fq_flow_head new_flows;
104 struct fq_flow_head old_flows;
105 int credit;
106 int quantum; /* based on band nr : 576KB, 192KB, 64KB */
107 };
108
109 #define FQ_PRIO2BAND_CRUMB_SIZE ((TC_PRIO_MAX + 1) >> 2)
110
111 struct fq_sched_data {
112 /* Read mostly cache line */
113
114 u32 quantum;
115 u32 initial_quantum;
116 u32 flow_refill_delay;
117 u32 flow_plimit; /* max packets per flow */
118 unsigned long flow_max_rate; /* optional max rate per flow */
119 u64 ce_threshold;
120 u64 horizon; /* horizon in ns */
121 u32 orphan_mask; /* mask for orphaned skb */
122 u32 low_rate_threshold;
123 struct rb_root *fq_root;
124 u8 rate_enable;
125 u8 fq_trees_log;
126 u8 horizon_drop;
127 u8 prio2band[FQ_PRIO2BAND_CRUMB_SIZE];
128 u32 timer_slack; /* hrtimer slack in ns */
129
130 /* Read/Write fields. */
131
132 unsigned int band_nr; /* band being serviced in fq_dequeue() */
133
134 struct fq_perband_flows band_flows[FQ_BANDS];
135
136 struct fq_flow internal; /* fastpath queue. */
137 struct rb_root delayed; /* for rate limited flows */
138 u64 time_next_delayed_flow;
139 unsigned long unthrottle_latency_ns;
140
141 u32 band_pkt_count[FQ_BANDS];
142 u32 flows;
143 u32 inactive_flows; /* Flows with no packet to send. */
144 u32 throttled_flows;
145
146 u64 stat_throttled;
147 struct qdisc_watchdog watchdog;
148 u64 stat_gc_flows;
149
150 /* Seldom used fields. */
151
152 u64 stat_band_drops[FQ_BANDS];
153 u64 stat_ce_mark;
154 u64 stat_horizon_drops;
155 u64 stat_horizon_caps;
156 u64 stat_flows_plimit;
157 u64 stat_pkts_too_long;
158 u64 stat_allocation_errors;
159 };
160
161 /* return the i-th 2-bit value ("crumb") */
fq_prio2band(const u8 * prio2band,unsigned int prio)162 static u8 fq_prio2band(const u8 *prio2band, unsigned int prio)
163 {
164 return (READ_ONCE(prio2band[prio / 4]) >> (2 * (prio & 0x3))) & 0x3;
165 }
166
167 /*
168 * f->tail and f->age share the same location.
169 * We can use the low order bit to differentiate if this location points
170 * to a sk_buff or contains a jiffies value, if we force this value to be odd.
171 * This assumes f->tail low order bit must be 0 since alignof(struct sk_buff) >= 2
172 */
fq_flow_set_detached(struct fq_flow * f)173 static void fq_flow_set_detached(struct fq_flow *f)
174 {
175 f->age = jiffies | 1UL;
176 }
177
fq_flow_is_detached(const struct fq_flow * f)178 static bool fq_flow_is_detached(const struct fq_flow *f)
179 {
180 return !!(f->age & 1UL);
181 }
182
183 /* special value to mark a throttled flow (not on old/new list) */
184 static struct fq_flow throttled;
185
fq_flow_is_throttled(const struct fq_flow * f)186 static bool fq_flow_is_throttled(const struct fq_flow *f)
187 {
188 return f->next == &throttled;
189 }
190
191 enum new_flow {
192 NEW_FLOW,
193 OLD_FLOW
194 };
195
fq_flow_add_tail(struct fq_sched_data * q,struct fq_flow * flow,enum new_flow list_sel)196 static void fq_flow_add_tail(struct fq_sched_data *q, struct fq_flow *flow,
197 enum new_flow list_sel)
198 {
199 struct fq_perband_flows *pband = &q->band_flows[flow->band];
200 struct fq_flow_head *head = (list_sel == NEW_FLOW) ?
201 &pband->new_flows :
202 &pband->old_flows;
203
204 if (head->first)
205 head->last->next = flow;
206 else
207 head->first = flow;
208 head->last = flow;
209 flow->next = NULL;
210 }
211
fq_flow_unset_throttled(struct fq_sched_data * q,struct fq_flow * f)212 static void fq_flow_unset_throttled(struct fq_sched_data *q, struct fq_flow *f)
213 {
214 rb_erase(&f->rate_node, &q->delayed);
215 q->throttled_flows--;
216 fq_flow_add_tail(q, f, OLD_FLOW);
217 }
218
fq_flow_set_throttled(struct fq_sched_data * q,struct fq_flow * f)219 static void fq_flow_set_throttled(struct fq_sched_data *q, struct fq_flow *f)
220 {
221 struct rb_node **p = &q->delayed.rb_node, *parent = NULL;
222
223 while (*p) {
224 struct fq_flow *aux;
225
226 parent = *p;
227 aux = rb_entry(parent, struct fq_flow, rate_node);
228 if (f->time_next_packet >= aux->time_next_packet)
229 p = &parent->rb_right;
230 else
231 p = &parent->rb_left;
232 }
233 rb_link_node(&f->rate_node, parent, p);
234 rb_insert_color(&f->rate_node, &q->delayed);
235 q->throttled_flows++;
236 q->stat_throttled++;
237
238 f->next = &throttled;
239 if (q->time_next_delayed_flow > f->time_next_packet)
240 q->time_next_delayed_flow = f->time_next_packet;
241 }
242
243
244 static struct kmem_cache *fq_flow_cachep __read_mostly;
245
246
247 /* limit number of collected flows per round */
248 #define FQ_GC_MAX 8
249 #define FQ_GC_AGE (3*HZ)
250
fq_gc_candidate(const struct fq_flow * f)251 static bool fq_gc_candidate(const struct fq_flow *f)
252 {
253 return fq_flow_is_detached(f) &&
254 time_after(jiffies, f->age + FQ_GC_AGE);
255 }
256
fq_gc(struct fq_sched_data * q,struct rb_root * root,struct sock * sk)257 static void fq_gc(struct fq_sched_data *q,
258 struct rb_root *root,
259 struct sock *sk)
260 {
261 struct rb_node **p, *parent;
262 void *tofree[FQ_GC_MAX];
263 struct fq_flow *f;
264 int i, fcnt = 0;
265
266 p = &root->rb_node;
267 parent = NULL;
268 while (*p) {
269 parent = *p;
270
271 f = rb_entry(parent, struct fq_flow, fq_node);
272 if (f->sk == sk)
273 break;
274
275 if (fq_gc_candidate(f)) {
276 tofree[fcnt++] = f;
277 if (fcnt == FQ_GC_MAX)
278 break;
279 }
280
281 if (f->sk > sk)
282 p = &parent->rb_right;
283 else
284 p = &parent->rb_left;
285 }
286
287 if (!fcnt)
288 return;
289
290 for (i = fcnt; i > 0; ) {
291 f = tofree[--i];
292 rb_erase(&f->fq_node, root);
293 }
294 q->flows -= fcnt;
295 q->inactive_flows -= fcnt;
296 q->stat_gc_flows += fcnt;
297
298 kmem_cache_free_bulk(fq_flow_cachep, fcnt, tofree);
299 }
300
301 /* Fast path can be used if :
302 * 1) Packet tstamp is in the past.
303 * 2) FQ qlen == 0 OR
304 * (no flow is currently eligible for transmit,
305 * AND fast path queue has less than 8 packets)
306 * 3) No SO_MAX_PACING_RATE on the socket (if any).
307 * 4) No @maxrate attribute on this qdisc,
308 *
309 * FQ can not use generic TCQ_F_CAN_BYPASS infrastructure.
310 */
fq_fastpath_check(const struct Qdisc * sch,struct sk_buff * skb,u64 now)311 static bool fq_fastpath_check(const struct Qdisc *sch, struct sk_buff *skb,
312 u64 now)
313 {
314 const struct fq_sched_data *q = qdisc_priv(sch);
315 const struct sock *sk;
316
317 if (fq_skb_cb(skb)->time_to_send > now)
318 return false;
319
320 if (sch->q.qlen != 0) {
321 /* Even if some packets are stored in this qdisc,
322 * we can still enable fast path if all of them are
323 * scheduled in the future (ie no flows are eligible)
324 * or in the fast path queue.
325 */
326 if (q->flows != q->inactive_flows + q->throttled_flows)
327 return false;
328
329 /* Do not allow fast path queue to explode, we want Fair Queue mode
330 * under pressure.
331 */
332 if (q->internal.qlen >= 8)
333 return false;
334 }
335
336 sk = skb->sk;
337 if (sk && sk_fullsock(sk) && !sk_is_tcp(sk) &&
338 sk->sk_max_pacing_rate != ~0UL)
339 return false;
340
341 if (q->flow_max_rate != ~0UL)
342 return false;
343
344 return true;
345 }
346
fq_classify(struct Qdisc * sch,struct sk_buff * skb,u64 now)347 static struct fq_flow *fq_classify(struct Qdisc *sch, struct sk_buff *skb,
348 u64 now)
349 {
350 struct fq_sched_data *q = qdisc_priv(sch);
351 struct rb_node **p, *parent;
352 struct sock *sk = skb->sk;
353 struct rb_root *root;
354 struct fq_flow *f;
355
356 /* SYNACK messages are attached to a TCP_NEW_SYN_RECV request socket
357 * or a listener (SYNCOOKIE mode)
358 * 1) request sockets are not full blown,
359 * they do not contain sk_pacing_rate
360 * 2) They are not part of a 'flow' yet
361 * 3) We do not want to rate limit them (eg SYNFLOOD attack),
362 * especially if the listener set SO_MAX_PACING_RATE
363 * 4) We pretend they are orphaned
364 */
365 if (!sk || sk_listener(sk)) {
366 unsigned long hash = skb_get_hash(skb) & q->orphan_mask;
367
368 /* By forcing low order bit to 1, we make sure to not
369 * collide with a local flow (socket pointers are word aligned)
370 */
371 sk = (struct sock *)((hash << 1) | 1UL);
372 skb_orphan(skb);
373 } else if (sk->sk_state == TCP_CLOSE) {
374 unsigned long hash = skb_get_hash(skb) & q->orphan_mask;
375 /*
376 * Sockets in TCP_CLOSE are non connected.
377 * Typical use case is UDP sockets, they can send packets
378 * with sendto() to many different destinations.
379 * We probably could use a generic bit advertising
380 * non connected sockets, instead of sk_state == TCP_CLOSE,
381 * if we care enough.
382 */
383 sk = (struct sock *)((hash << 1) | 1UL);
384 }
385
386 if (fq_fastpath_check(sch, skb, now)) {
387 q->internal.stat_fastpath_packets++;
388 if (skb->sk == sk && q->rate_enable &&
389 READ_ONCE(sk->sk_pacing_status) != SK_PACING_FQ)
390 smp_store_release(&sk->sk_pacing_status,
391 SK_PACING_FQ);
392 return &q->internal;
393 }
394
395 root = &q->fq_root[hash_ptr(sk, q->fq_trees_log)];
396
397 fq_gc(q, root, sk);
398
399 p = &root->rb_node;
400 parent = NULL;
401 while (*p) {
402 parent = *p;
403
404 f = rb_entry(parent, struct fq_flow, fq_node);
405 if (f->sk == sk) {
406 /* socket might have been reallocated, so check
407 * if its sk_hash is the same.
408 * It not, we need to refill credit with
409 * initial quantum
410 */
411 if (unlikely(skb->sk == sk &&
412 f->socket_hash != sk->sk_hash)) {
413 f->credit = q->initial_quantum;
414 f->socket_hash = sk->sk_hash;
415 if (q->rate_enable)
416 smp_store_release(&sk->sk_pacing_status,
417 SK_PACING_FQ);
418 if (fq_flow_is_throttled(f))
419 fq_flow_unset_throttled(q, f);
420 f->time_next_packet = 0ULL;
421 }
422 return f;
423 }
424 if (f->sk > sk)
425 p = &parent->rb_right;
426 else
427 p = &parent->rb_left;
428 }
429
430 f = kmem_cache_zalloc(fq_flow_cachep, GFP_ATOMIC | __GFP_NOWARN);
431 if (unlikely(!f)) {
432 q->stat_allocation_errors++;
433 return &q->internal;
434 }
435 /* f->t_root is already zeroed after kmem_cache_zalloc() */
436
437 fq_flow_set_detached(f);
438 f->sk = sk;
439 if (skb->sk == sk) {
440 f->socket_hash = sk->sk_hash;
441 if (q->rate_enable)
442 smp_store_release(&sk->sk_pacing_status,
443 SK_PACING_FQ);
444 }
445 f->credit = q->initial_quantum;
446
447 rb_link_node(&f->fq_node, parent, p);
448 rb_insert_color(&f->fq_node, root);
449
450 q->flows++;
451 q->inactive_flows++;
452 return f;
453 }
454
fq_peek(struct fq_flow * flow)455 static struct sk_buff *fq_peek(struct fq_flow *flow)
456 {
457 struct sk_buff *skb = skb_rb_first(&flow->t_root);
458 struct sk_buff *head = flow->head;
459
460 if (!skb)
461 return head;
462
463 if (!head)
464 return skb;
465
466 if (fq_skb_cb(skb)->time_to_send < fq_skb_cb(head)->time_to_send)
467 return skb;
468 return head;
469 }
470
fq_erase_head(struct Qdisc * sch,struct fq_flow * flow,struct sk_buff * skb)471 static void fq_erase_head(struct Qdisc *sch, struct fq_flow *flow,
472 struct sk_buff *skb)
473 {
474 if (skb == flow->head) {
475 flow->head = skb->next;
476 } else {
477 rb_erase(&skb->rbnode, &flow->t_root);
478 skb->dev = qdisc_dev(sch);
479 }
480 }
481
482 /* Remove one skb from flow queue.
483 * This skb must be the return value of prior fq_peek().
484 */
fq_dequeue_skb(struct Qdisc * sch,struct fq_flow * flow,struct sk_buff * skb)485 static void fq_dequeue_skb(struct Qdisc *sch, struct fq_flow *flow,
486 struct sk_buff *skb)
487 {
488 fq_erase_head(sch, flow, skb);
489 skb_mark_not_on_list(skb);
490 qdisc_qstats_backlog_dec(sch, skb);
491 sch->q.qlen--;
492 }
493
flow_queue_add(struct fq_flow * flow,struct sk_buff * skb)494 static void flow_queue_add(struct fq_flow *flow, struct sk_buff *skb)
495 {
496 struct rb_node **p, *parent;
497 struct sk_buff *head, *aux;
498
499 head = flow->head;
500 if (!head ||
501 fq_skb_cb(skb)->time_to_send >= fq_skb_cb(flow->tail)->time_to_send) {
502 if (!head)
503 flow->head = skb;
504 else
505 flow->tail->next = skb;
506 flow->tail = skb;
507 skb->next = NULL;
508 return;
509 }
510
511 p = &flow->t_root.rb_node;
512 parent = NULL;
513
514 while (*p) {
515 parent = *p;
516 aux = rb_to_skb(parent);
517 if (fq_skb_cb(skb)->time_to_send >= fq_skb_cb(aux)->time_to_send)
518 p = &parent->rb_right;
519 else
520 p = &parent->rb_left;
521 }
522 rb_link_node(&skb->rbnode, parent, p);
523 rb_insert_color(&skb->rbnode, &flow->t_root);
524 }
525
fq_packet_beyond_horizon(const struct sk_buff * skb,const struct fq_sched_data * q,u64 now)526 static bool fq_packet_beyond_horizon(const struct sk_buff *skb,
527 const struct fq_sched_data *q, u64 now)
528 {
529 return unlikely((s64)skb->tstamp > (s64)(now + q->horizon));
530 }
531
fq_enqueue(struct sk_buff * skb,struct Qdisc * sch,struct sk_buff ** to_free)532 static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch,
533 struct sk_buff **to_free)
534 {
535 struct fq_sched_data *q = qdisc_priv(sch);
536 struct fq_flow *f;
537 u64 now;
538 u8 band;
539
540 band = fq_prio2band(q->prio2band, skb->priority & TC_PRIO_MAX);
541 if (unlikely(q->band_pkt_count[band] >= sch->limit)) {
542 q->stat_band_drops[band]++;
543 return qdisc_drop(skb, sch, to_free);
544 }
545
546 now = ktime_get_ns();
547 if (!skb->tstamp) {
548 fq_skb_cb(skb)->time_to_send = now;
549 } else {
550 /* Check if packet timestamp is too far in the future. */
551 if (fq_packet_beyond_horizon(skb, q, now)) {
552 if (q->horizon_drop) {
553 q->stat_horizon_drops++;
554 return qdisc_drop(skb, sch, to_free);
555 }
556 q->stat_horizon_caps++;
557 skb->tstamp = now + q->horizon;
558 }
559 fq_skb_cb(skb)->time_to_send = skb->tstamp;
560 }
561
562 f = fq_classify(sch, skb, now);
563
564 if (f != &q->internal) {
565 if (unlikely(f->qlen >= q->flow_plimit)) {
566 q->stat_flows_plimit++;
567 return qdisc_drop(skb, sch, to_free);
568 }
569
570 if (fq_flow_is_detached(f)) {
571 fq_flow_add_tail(q, f, NEW_FLOW);
572 if (time_after(jiffies, f->age + q->flow_refill_delay))
573 f->credit = max_t(u32, f->credit, q->quantum);
574 }
575
576 f->band = band;
577 q->band_pkt_count[band]++;
578 fq_skb_cb(skb)->band = band;
579 if (f->qlen == 0)
580 q->inactive_flows--;
581 }
582
583 f->qlen++;
584 /* Note: this overwrites f->age */
585 flow_queue_add(f, skb);
586
587 qdisc_qstats_backlog_inc(sch, skb);
588 sch->q.qlen++;
589
590 return NET_XMIT_SUCCESS;
591 }
592
fq_check_throttled(struct fq_sched_data * q,u64 now)593 static void fq_check_throttled(struct fq_sched_data *q, u64 now)
594 {
595 unsigned long sample;
596 struct rb_node *p;
597
598 if (q->time_next_delayed_flow > now)
599 return;
600
601 /* Update unthrottle latency EWMA.
602 * This is cheap and can help diagnosing timer/latency problems.
603 */
604 sample = (unsigned long)(now - q->time_next_delayed_flow);
605 q->unthrottle_latency_ns -= q->unthrottle_latency_ns >> 3;
606 q->unthrottle_latency_ns += sample >> 3;
607
608 q->time_next_delayed_flow = ~0ULL;
609 while ((p = rb_first(&q->delayed)) != NULL) {
610 struct fq_flow *f = rb_entry(p, struct fq_flow, rate_node);
611
612 if (f->time_next_packet > now) {
613 q->time_next_delayed_flow = f->time_next_packet;
614 break;
615 }
616 fq_flow_unset_throttled(q, f);
617 }
618 }
619
fq_pband_head_select(struct fq_perband_flows * pband)620 static struct fq_flow_head *fq_pband_head_select(struct fq_perband_flows *pband)
621 {
622 if (pband->credit <= 0)
623 return NULL;
624
625 if (pband->new_flows.first)
626 return &pband->new_flows;
627
628 return pband->old_flows.first ? &pband->old_flows : NULL;
629 }
630
fq_dequeue(struct Qdisc * sch)631 static struct sk_buff *fq_dequeue(struct Qdisc *sch)
632 {
633 struct fq_sched_data *q = qdisc_priv(sch);
634 struct fq_perband_flows *pband;
635 struct fq_flow_head *head;
636 struct sk_buff *skb;
637 struct fq_flow *f;
638 unsigned long rate;
639 int retry;
640 u32 plen;
641 u64 now;
642
643 if (!sch->q.qlen)
644 return NULL;
645
646 skb = fq_peek(&q->internal);
647 if (unlikely(skb)) {
648 q->internal.qlen--;
649 fq_dequeue_skb(sch, &q->internal, skb);
650 goto out;
651 }
652
653 now = ktime_get_ns();
654 fq_check_throttled(q, now);
655 retry = 0;
656 pband = &q->band_flows[q->band_nr];
657 begin:
658 head = fq_pband_head_select(pband);
659 if (!head) {
660 while (++retry <= FQ_BANDS) {
661 if (++q->band_nr == FQ_BANDS)
662 q->band_nr = 0;
663 pband = &q->band_flows[q->band_nr];
664 pband->credit = min(pband->credit + pband->quantum,
665 pband->quantum);
666 if (pband->credit > 0)
667 goto begin;
668 retry = 0;
669 }
670 if (q->time_next_delayed_flow != ~0ULL)
671 qdisc_watchdog_schedule_range_ns(&q->watchdog,
672 q->time_next_delayed_flow,
673 q->timer_slack);
674 return NULL;
675 }
676 f = head->first;
677 retry = 0;
678 if (f->credit <= 0) {
679 f->credit += q->quantum;
680 head->first = f->next;
681 fq_flow_add_tail(q, f, OLD_FLOW);
682 goto begin;
683 }
684
685 skb = fq_peek(f);
686 if (skb) {
687 u64 time_next_packet = max_t(u64, fq_skb_cb(skb)->time_to_send,
688 f->time_next_packet);
689
690 if (now < time_next_packet) {
691 head->first = f->next;
692 f->time_next_packet = time_next_packet;
693 fq_flow_set_throttled(q, f);
694 goto begin;
695 }
696 prefetch(&skb->end);
697 if ((s64)(now - time_next_packet - q->ce_threshold) > 0) {
698 INET_ECN_set_ce(skb);
699 q->stat_ce_mark++;
700 }
701 if (--f->qlen == 0)
702 q->inactive_flows++;
703 q->band_pkt_count[fq_skb_cb(skb)->band]--;
704 fq_dequeue_skb(sch, f, skb);
705 } else {
706 head->first = f->next;
707 /* force a pass through old_flows to prevent starvation */
708 if (head == &pband->new_flows) {
709 fq_flow_add_tail(q, f, OLD_FLOW);
710 } else {
711 fq_flow_set_detached(f);
712 }
713 goto begin;
714 }
715 plen = qdisc_pkt_len(skb);
716 f->credit -= plen;
717 pband->credit -= plen;
718
719 if (!q->rate_enable)
720 goto out;
721
722 rate = q->flow_max_rate;
723
724 /* If EDT time was provided for this skb, we need to
725 * update f->time_next_packet only if this qdisc enforces
726 * a flow max rate.
727 */
728 if (!skb->tstamp) {
729 if (skb->sk)
730 rate = min(READ_ONCE(skb->sk->sk_pacing_rate), rate);
731
732 if (rate <= q->low_rate_threshold) {
733 f->credit = 0;
734 } else {
735 plen = max(plen, q->quantum);
736 if (f->credit > 0)
737 goto out;
738 }
739 }
740 if (rate != ~0UL) {
741 u64 len = (u64)plen * NSEC_PER_SEC;
742
743 if (likely(rate))
744 len = div64_ul(len, rate);
745 /* Since socket rate can change later,
746 * clamp the delay to 1 second.
747 * Really, providers of too big packets should be fixed !
748 */
749 if (unlikely(len > NSEC_PER_SEC)) {
750 len = NSEC_PER_SEC;
751 q->stat_pkts_too_long++;
752 }
753 /* Account for schedule/timers drifts.
754 * f->time_next_packet was set when prior packet was sent,
755 * and current time (@now) can be too late by tens of us.
756 */
757 if (f->time_next_packet)
758 len -= min(len/2, now - f->time_next_packet);
759 f->time_next_packet = now + len;
760 }
761 out:
762 qdisc_bstats_update(sch, skb);
763 return skb;
764 }
765
fq_flow_purge(struct fq_flow * flow)766 static void fq_flow_purge(struct fq_flow *flow)
767 {
768 struct rb_node *p = rb_first(&flow->t_root);
769
770 while (p) {
771 struct sk_buff *skb = rb_to_skb(p);
772
773 p = rb_next(p);
774 rb_erase(&skb->rbnode, &flow->t_root);
775 rtnl_kfree_skbs(skb, skb);
776 }
777 rtnl_kfree_skbs(flow->head, flow->tail);
778 flow->head = NULL;
779 flow->qlen = 0;
780 }
781
fq_reset(struct Qdisc * sch)782 static void fq_reset(struct Qdisc *sch)
783 {
784 struct fq_sched_data *q = qdisc_priv(sch);
785 struct rb_root *root;
786 struct rb_node *p;
787 struct fq_flow *f;
788 unsigned int idx;
789
790 sch->q.qlen = 0;
791 sch->qstats.backlog = 0;
792
793 fq_flow_purge(&q->internal);
794
795 if (!q->fq_root)
796 return;
797
798 for (idx = 0; idx < (1U << q->fq_trees_log); idx++) {
799 root = &q->fq_root[idx];
800 while ((p = rb_first(root)) != NULL) {
801 f = rb_entry(p, struct fq_flow, fq_node);
802 rb_erase(p, root);
803
804 fq_flow_purge(f);
805
806 kmem_cache_free(fq_flow_cachep, f);
807 }
808 }
809 for (idx = 0; idx < FQ_BANDS; idx++) {
810 q->band_flows[idx].new_flows.first = NULL;
811 q->band_flows[idx].old_flows.first = NULL;
812 }
813 q->delayed = RB_ROOT;
814 q->flows = 0;
815 q->inactive_flows = 0;
816 q->throttled_flows = 0;
817 }
818
fq_rehash(struct fq_sched_data * q,struct rb_root * old_array,u32 old_log,struct rb_root * new_array,u32 new_log)819 static void fq_rehash(struct fq_sched_data *q,
820 struct rb_root *old_array, u32 old_log,
821 struct rb_root *new_array, u32 new_log)
822 {
823 struct rb_node *op, **np, *parent;
824 struct rb_root *oroot, *nroot;
825 struct fq_flow *of, *nf;
826 int fcnt = 0;
827 u32 idx;
828
829 for (idx = 0; idx < (1U << old_log); idx++) {
830 oroot = &old_array[idx];
831 while ((op = rb_first(oroot)) != NULL) {
832 rb_erase(op, oroot);
833 of = rb_entry(op, struct fq_flow, fq_node);
834 if (fq_gc_candidate(of)) {
835 fcnt++;
836 kmem_cache_free(fq_flow_cachep, of);
837 continue;
838 }
839 nroot = &new_array[hash_ptr(of->sk, new_log)];
840
841 np = &nroot->rb_node;
842 parent = NULL;
843 while (*np) {
844 parent = *np;
845
846 nf = rb_entry(parent, struct fq_flow, fq_node);
847 BUG_ON(nf->sk == of->sk);
848
849 if (nf->sk > of->sk)
850 np = &parent->rb_right;
851 else
852 np = &parent->rb_left;
853 }
854
855 rb_link_node(&of->fq_node, parent, np);
856 rb_insert_color(&of->fq_node, nroot);
857 }
858 }
859 q->flows -= fcnt;
860 q->inactive_flows -= fcnt;
861 q->stat_gc_flows += fcnt;
862 }
863
fq_free(void * addr)864 static void fq_free(void *addr)
865 {
866 kvfree(addr);
867 }
868
fq_resize(struct Qdisc * sch,u32 log)869 static int fq_resize(struct Qdisc *sch, u32 log)
870 {
871 struct fq_sched_data *q = qdisc_priv(sch);
872 struct rb_root *array;
873 void *old_fq_root;
874 u32 idx;
875
876 if (q->fq_root && log == q->fq_trees_log)
877 return 0;
878
879 /* If XPS was setup, we can allocate memory on right NUMA node */
880 array = kvmalloc_node(sizeof(struct rb_root) << log, GFP_KERNEL | __GFP_RETRY_MAYFAIL,
881 netdev_queue_numa_node_read(sch->dev_queue));
882 if (!array)
883 return -ENOMEM;
884
885 for (idx = 0; idx < (1U << log); idx++)
886 array[idx] = RB_ROOT;
887
888 sch_tree_lock(sch);
889
890 old_fq_root = q->fq_root;
891 if (old_fq_root)
892 fq_rehash(q, old_fq_root, q->fq_trees_log, array, log);
893
894 q->fq_root = array;
895 WRITE_ONCE(q->fq_trees_log, log);
896
897 sch_tree_unlock(sch);
898
899 fq_free(old_fq_root);
900
901 return 0;
902 }
903
904 static const struct netlink_range_validation iq_range = {
905 .max = INT_MAX,
906 };
907
908 static const struct nla_policy fq_policy[TCA_FQ_MAX + 1] = {
909 [TCA_FQ_UNSPEC] = { .strict_start_type = TCA_FQ_TIMER_SLACK },
910
911 [TCA_FQ_PLIMIT] = { .type = NLA_U32 },
912 [TCA_FQ_FLOW_PLIMIT] = { .type = NLA_U32 },
913 [TCA_FQ_QUANTUM] = { .type = NLA_U32 },
914 [TCA_FQ_INITIAL_QUANTUM] = NLA_POLICY_FULL_RANGE(NLA_U32, &iq_range),
915 [TCA_FQ_RATE_ENABLE] = { .type = NLA_U32 },
916 [TCA_FQ_FLOW_DEFAULT_RATE] = { .type = NLA_U32 },
917 [TCA_FQ_FLOW_MAX_RATE] = { .type = NLA_U32 },
918 [TCA_FQ_BUCKETS_LOG] = { .type = NLA_U32 },
919 [TCA_FQ_FLOW_REFILL_DELAY] = { .type = NLA_U32 },
920 [TCA_FQ_ORPHAN_MASK] = { .type = NLA_U32 },
921 [TCA_FQ_LOW_RATE_THRESHOLD] = { .type = NLA_U32 },
922 [TCA_FQ_CE_THRESHOLD] = { .type = NLA_U32 },
923 [TCA_FQ_TIMER_SLACK] = { .type = NLA_U32 },
924 [TCA_FQ_HORIZON] = { .type = NLA_U32 },
925 [TCA_FQ_HORIZON_DROP] = { .type = NLA_U8 },
926 [TCA_FQ_PRIOMAP] = NLA_POLICY_EXACT_LEN(sizeof(struct tc_prio_qopt)),
927 [TCA_FQ_WEIGHTS] = NLA_POLICY_EXACT_LEN(FQ_BANDS * sizeof(s32)),
928 };
929
930 /* compress a u8 array with all elems <= 3 to an array of 2-bit fields */
fq_prio2band_compress_crumb(const u8 * in,u8 * out)931 static void fq_prio2band_compress_crumb(const u8 *in, u8 *out)
932 {
933 const int num_elems = TC_PRIO_MAX + 1;
934 u8 tmp[FQ_PRIO2BAND_CRUMB_SIZE];
935 int i;
936
937 memset(tmp, 0, sizeof(tmp));
938 for (i = 0; i < num_elems; i++)
939 tmp[i / 4] |= in[i] << (2 * (i & 0x3));
940
941 for (i = 0; i < FQ_PRIO2BAND_CRUMB_SIZE; i++)
942 WRITE_ONCE(out[i], tmp[i]);
943 }
944
fq_prio2band_decompress_crumb(const u8 * in,u8 * out)945 static void fq_prio2band_decompress_crumb(const u8 *in, u8 *out)
946 {
947 const int num_elems = TC_PRIO_MAX + 1;
948 int i;
949
950 for (i = 0; i < num_elems; i++)
951 out[i] = fq_prio2band(in, i);
952 }
953
fq_load_weights(struct fq_sched_data * q,const struct nlattr * attr,struct netlink_ext_ack * extack)954 static int fq_load_weights(struct fq_sched_data *q,
955 const struct nlattr *attr,
956 struct netlink_ext_ack *extack)
957 {
958 s32 *weights = nla_data(attr);
959 int i;
960
961 for (i = 0; i < FQ_BANDS; i++) {
962 if (weights[i] < FQ_MIN_WEIGHT) {
963 NL_SET_ERR_MSG_FMT_MOD(extack, "Weight %d less that minimum allowed %d",
964 weights[i], FQ_MIN_WEIGHT);
965 return -EINVAL;
966 }
967 }
968 for (i = 0; i < FQ_BANDS; i++)
969 WRITE_ONCE(q->band_flows[i].quantum, weights[i]);
970 return 0;
971 }
972
fq_load_priomap(struct fq_sched_data * q,const struct nlattr * attr,struct netlink_ext_ack * extack)973 static int fq_load_priomap(struct fq_sched_data *q,
974 const struct nlattr *attr,
975 struct netlink_ext_ack *extack)
976 {
977 const struct tc_prio_qopt *map = nla_data(attr);
978 int i;
979
980 if (map->bands != FQ_BANDS) {
981 NL_SET_ERR_MSG_MOD(extack, "FQ only supports 3 bands");
982 return -EINVAL;
983 }
984 for (i = 0; i < TC_PRIO_MAX + 1; i++) {
985 if (map->priomap[i] >= FQ_BANDS) {
986 NL_SET_ERR_MSG_FMT_MOD(extack, "FQ priomap field %d maps to a too high band %d",
987 i, map->priomap[i]);
988 return -EINVAL;
989 }
990 }
991 fq_prio2band_compress_crumb(map->priomap, q->prio2band);
992 return 0;
993 }
994
fq_change(struct Qdisc * sch,struct nlattr * opt,struct netlink_ext_ack * extack)995 static int fq_change(struct Qdisc *sch, struct nlattr *opt,
996 struct netlink_ext_ack *extack)
997 {
998 struct fq_sched_data *q = qdisc_priv(sch);
999 struct nlattr *tb[TCA_FQ_MAX + 1];
1000 int err, drop_count = 0;
1001 unsigned drop_len = 0;
1002 u32 fq_log;
1003
1004 err = nla_parse_nested_deprecated(tb, TCA_FQ_MAX, opt, fq_policy,
1005 NULL);
1006 if (err < 0)
1007 return err;
1008
1009 sch_tree_lock(sch);
1010
1011 fq_log = q->fq_trees_log;
1012
1013 if (tb[TCA_FQ_BUCKETS_LOG]) {
1014 u32 nval = nla_get_u32(tb[TCA_FQ_BUCKETS_LOG]);
1015
1016 if (nval >= 1 && nval <= ilog2(256*1024))
1017 fq_log = nval;
1018 else
1019 err = -EINVAL;
1020 }
1021 if (tb[TCA_FQ_PLIMIT])
1022 WRITE_ONCE(sch->limit,
1023 nla_get_u32(tb[TCA_FQ_PLIMIT]));
1024
1025 if (tb[TCA_FQ_FLOW_PLIMIT])
1026 WRITE_ONCE(q->flow_plimit,
1027 nla_get_u32(tb[TCA_FQ_FLOW_PLIMIT]));
1028
1029 if (tb[TCA_FQ_QUANTUM]) {
1030 u32 quantum = nla_get_u32(tb[TCA_FQ_QUANTUM]);
1031
1032 if (quantum > 0 && quantum <= (1 << 20)) {
1033 WRITE_ONCE(q->quantum, quantum);
1034 } else {
1035 NL_SET_ERR_MSG_MOD(extack, "invalid quantum");
1036 err = -EINVAL;
1037 }
1038 }
1039
1040 if (tb[TCA_FQ_INITIAL_QUANTUM])
1041 WRITE_ONCE(q->initial_quantum,
1042 nla_get_u32(tb[TCA_FQ_INITIAL_QUANTUM]));
1043
1044 if (tb[TCA_FQ_FLOW_DEFAULT_RATE])
1045 pr_warn_ratelimited("sch_fq: defrate %u ignored.\n",
1046 nla_get_u32(tb[TCA_FQ_FLOW_DEFAULT_RATE]));
1047
1048 if (tb[TCA_FQ_FLOW_MAX_RATE]) {
1049 u32 rate = nla_get_u32(tb[TCA_FQ_FLOW_MAX_RATE]);
1050
1051 WRITE_ONCE(q->flow_max_rate,
1052 (rate == ~0U) ? ~0UL : rate);
1053 }
1054 if (tb[TCA_FQ_LOW_RATE_THRESHOLD])
1055 WRITE_ONCE(q->low_rate_threshold,
1056 nla_get_u32(tb[TCA_FQ_LOW_RATE_THRESHOLD]));
1057
1058 if (tb[TCA_FQ_RATE_ENABLE]) {
1059 u32 enable = nla_get_u32(tb[TCA_FQ_RATE_ENABLE]);
1060
1061 if (enable <= 1)
1062 WRITE_ONCE(q->rate_enable,
1063 enable);
1064 else
1065 err = -EINVAL;
1066 }
1067
1068 if (tb[TCA_FQ_FLOW_REFILL_DELAY]) {
1069 u32 usecs_delay = nla_get_u32(tb[TCA_FQ_FLOW_REFILL_DELAY]) ;
1070
1071 WRITE_ONCE(q->flow_refill_delay,
1072 usecs_to_jiffies(usecs_delay));
1073 }
1074
1075 if (!err && tb[TCA_FQ_PRIOMAP])
1076 err = fq_load_priomap(q, tb[TCA_FQ_PRIOMAP], extack);
1077
1078 if (!err && tb[TCA_FQ_WEIGHTS])
1079 err = fq_load_weights(q, tb[TCA_FQ_WEIGHTS], extack);
1080
1081 if (tb[TCA_FQ_ORPHAN_MASK])
1082 WRITE_ONCE(q->orphan_mask,
1083 nla_get_u32(tb[TCA_FQ_ORPHAN_MASK]));
1084
1085 if (tb[TCA_FQ_CE_THRESHOLD])
1086 WRITE_ONCE(q->ce_threshold,
1087 (u64)NSEC_PER_USEC *
1088 nla_get_u32(tb[TCA_FQ_CE_THRESHOLD]));
1089
1090 if (tb[TCA_FQ_TIMER_SLACK])
1091 WRITE_ONCE(q->timer_slack,
1092 nla_get_u32(tb[TCA_FQ_TIMER_SLACK]));
1093
1094 if (tb[TCA_FQ_HORIZON])
1095 WRITE_ONCE(q->horizon,
1096 (u64)NSEC_PER_USEC *
1097 nla_get_u32(tb[TCA_FQ_HORIZON]));
1098
1099 if (tb[TCA_FQ_HORIZON_DROP])
1100 WRITE_ONCE(q->horizon_drop,
1101 nla_get_u8(tb[TCA_FQ_HORIZON_DROP]));
1102
1103 if (!err) {
1104
1105 sch_tree_unlock(sch);
1106 err = fq_resize(sch, fq_log);
1107 sch_tree_lock(sch);
1108 }
1109 while (sch->q.qlen > sch->limit) {
1110 struct sk_buff *skb = fq_dequeue(sch);
1111
1112 if (!skb)
1113 break;
1114 drop_len += qdisc_pkt_len(skb);
1115 rtnl_kfree_skbs(skb, skb);
1116 drop_count++;
1117 }
1118 qdisc_tree_reduce_backlog(sch, drop_count, drop_len);
1119
1120 sch_tree_unlock(sch);
1121 return err;
1122 }
1123
fq_destroy(struct Qdisc * sch)1124 static void fq_destroy(struct Qdisc *sch)
1125 {
1126 struct fq_sched_data *q = qdisc_priv(sch);
1127
1128 fq_reset(sch);
1129 fq_free(q->fq_root);
1130 qdisc_watchdog_cancel(&q->watchdog);
1131 }
1132
fq_init(struct Qdisc * sch,struct nlattr * opt,struct netlink_ext_ack * extack)1133 static int fq_init(struct Qdisc *sch, struct nlattr *opt,
1134 struct netlink_ext_ack *extack)
1135 {
1136 struct fq_sched_data *q = qdisc_priv(sch);
1137 int i, err;
1138
1139 sch->limit = 10000;
1140 q->flow_plimit = 100;
1141 q->quantum = 2 * psched_mtu(qdisc_dev(sch));
1142 q->initial_quantum = 10 * psched_mtu(qdisc_dev(sch));
1143 q->flow_refill_delay = msecs_to_jiffies(40);
1144 q->flow_max_rate = ~0UL;
1145 q->time_next_delayed_flow = ~0ULL;
1146 q->rate_enable = 1;
1147 for (i = 0; i < FQ_BANDS; i++) {
1148 q->band_flows[i].new_flows.first = NULL;
1149 q->band_flows[i].old_flows.first = NULL;
1150 }
1151 q->band_flows[0].quantum = 9 << 16;
1152 q->band_flows[1].quantum = 3 << 16;
1153 q->band_flows[2].quantum = 1 << 16;
1154 q->delayed = RB_ROOT;
1155 q->fq_root = NULL;
1156 q->fq_trees_log = ilog2(1024);
1157 q->orphan_mask = 1024 - 1;
1158 q->low_rate_threshold = 550000 / 8;
1159
1160 q->timer_slack = 10 * NSEC_PER_USEC; /* 10 usec of hrtimer slack */
1161
1162 q->horizon = 10ULL * NSEC_PER_SEC; /* 10 seconds */
1163 q->horizon_drop = 1; /* by default, drop packets beyond horizon */
1164
1165 /* Default ce_threshold of 4294 seconds */
1166 q->ce_threshold = (u64)NSEC_PER_USEC * ~0U;
1167
1168 fq_prio2band_compress_crumb(sch_default_prio2band, q->prio2band);
1169 qdisc_watchdog_init_clockid(&q->watchdog, sch, CLOCK_MONOTONIC);
1170
1171 if (opt)
1172 err = fq_change(sch, opt, extack);
1173 else
1174 err = fq_resize(sch, q->fq_trees_log);
1175
1176 return err;
1177 }
1178
fq_dump(struct Qdisc * sch,struct sk_buff * skb)1179 static int fq_dump(struct Qdisc *sch, struct sk_buff *skb)
1180 {
1181 struct fq_sched_data *q = qdisc_priv(sch);
1182 struct tc_prio_qopt prio = {
1183 .bands = FQ_BANDS,
1184 };
1185 struct nlattr *opts;
1186 u64 ce_threshold;
1187 s32 weights[3];
1188 u64 horizon;
1189
1190 opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
1191 if (opts == NULL)
1192 goto nla_put_failure;
1193
1194 /* TCA_FQ_FLOW_DEFAULT_RATE is not used anymore */
1195
1196 ce_threshold = READ_ONCE(q->ce_threshold);
1197 do_div(ce_threshold, NSEC_PER_USEC);
1198
1199 horizon = READ_ONCE(q->horizon);
1200 do_div(horizon, NSEC_PER_USEC);
1201
1202 if (nla_put_u32(skb, TCA_FQ_PLIMIT,
1203 READ_ONCE(sch->limit)) ||
1204 nla_put_u32(skb, TCA_FQ_FLOW_PLIMIT,
1205 READ_ONCE(q->flow_plimit)) ||
1206 nla_put_u32(skb, TCA_FQ_QUANTUM,
1207 READ_ONCE(q->quantum)) ||
1208 nla_put_u32(skb, TCA_FQ_INITIAL_QUANTUM,
1209 READ_ONCE(q->initial_quantum)) ||
1210 nla_put_u32(skb, TCA_FQ_RATE_ENABLE,
1211 READ_ONCE(q->rate_enable)) ||
1212 nla_put_u32(skb, TCA_FQ_FLOW_MAX_RATE,
1213 min_t(unsigned long,
1214 READ_ONCE(q->flow_max_rate), ~0U)) ||
1215 nla_put_u32(skb, TCA_FQ_FLOW_REFILL_DELAY,
1216 jiffies_to_usecs(READ_ONCE(q->flow_refill_delay))) ||
1217 nla_put_u32(skb, TCA_FQ_ORPHAN_MASK,
1218 READ_ONCE(q->orphan_mask)) ||
1219 nla_put_u32(skb, TCA_FQ_LOW_RATE_THRESHOLD,
1220 READ_ONCE(q->low_rate_threshold)) ||
1221 nla_put_u32(skb, TCA_FQ_CE_THRESHOLD, (u32)ce_threshold) ||
1222 nla_put_u32(skb, TCA_FQ_BUCKETS_LOG,
1223 READ_ONCE(q->fq_trees_log)) ||
1224 nla_put_u32(skb, TCA_FQ_TIMER_SLACK,
1225 READ_ONCE(q->timer_slack)) ||
1226 nla_put_u32(skb, TCA_FQ_HORIZON, (u32)horizon) ||
1227 nla_put_u8(skb, TCA_FQ_HORIZON_DROP,
1228 READ_ONCE(q->horizon_drop)))
1229 goto nla_put_failure;
1230
1231 fq_prio2band_decompress_crumb(q->prio2band, prio.priomap);
1232 if (nla_put(skb, TCA_FQ_PRIOMAP, sizeof(prio), &prio))
1233 goto nla_put_failure;
1234
1235 weights[0] = READ_ONCE(q->band_flows[0].quantum);
1236 weights[1] = READ_ONCE(q->band_flows[1].quantum);
1237 weights[2] = READ_ONCE(q->band_flows[2].quantum);
1238 if (nla_put(skb, TCA_FQ_WEIGHTS, sizeof(weights), &weights))
1239 goto nla_put_failure;
1240
1241 return nla_nest_end(skb, opts);
1242
1243 nla_put_failure:
1244 return -1;
1245 }
1246
fq_dump_stats(struct Qdisc * sch,struct gnet_dump * d)1247 static int fq_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
1248 {
1249 struct fq_sched_data *q = qdisc_priv(sch);
1250 struct tc_fq_qd_stats st;
1251 int i;
1252
1253 st.pad = 0;
1254
1255 sch_tree_lock(sch);
1256
1257 st.gc_flows = q->stat_gc_flows;
1258 st.highprio_packets = 0;
1259 st.fastpath_packets = q->internal.stat_fastpath_packets;
1260 st.tcp_retrans = 0;
1261 st.throttled = q->stat_throttled;
1262 st.flows_plimit = q->stat_flows_plimit;
1263 st.pkts_too_long = q->stat_pkts_too_long;
1264 st.allocation_errors = q->stat_allocation_errors;
1265 st.time_next_delayed_flow = q->time_next_delayed_flow + q->timer_slack -
1266 ktime_get_ns();
1267 st.flows = q->flows;
1268 st.inactive_flows = q->inactive_flows;
1269 st.throttled_flows = q->throttled_flows;
1270 st.unthrottle_latency_ns = min_t(unsigned long,
1271 q->unthrottle_latency_ns, ~0U);
1272 st.ce_mark = q->stat_ce_mark;
1273 st.horizon_drops = q->stat_horizon_drops;
1274 st.horizon_caps = q->stat_horizon_caps;
1275 for (i = 0; i < FQ_BANDS; i++) {
1276 st.band_drops[i] = q->stat_band_drops[i];
1277 st.band_pkt_count[i] = q->band_pkt_count[i];
1278 }
1279 sch_tree_unlock(sch);
1280
1281 return gnet_stats_copy_app(d, &st, sizeof(st));
1282 }
1283
1284 static struct Qdisc_ops fq_qdisc_ops __read_mostly = {
1285 .id = "fq",
1286 .priv_size = sizeof(struct fq_sched_data),
1287
1288 .enqueue = fq_enqueue,
1289 .dequeue = fq_dequeue,
1290 .peek = qdisc_peek_dequeued,
1291 .init = fq_init,
1292 .reset = fq_reset,
1293 .destroy = fq_destroy,
1294 .change = fq_change,
1295 .dump = fq_dump,
1296 .dump_stats = fq_dump_stats,
1297 .owner = THIS_MODULE,
1298 };
1299 MODULE_ALIAS_NET_SCH("fq");
1300
fq_module_init(void)1301 static int __init fq_module_init(void)
1302 {
1303 int ret;
1304
1305 fq_flow_cachep = kmem_cache_create("fq_flow_cache",
1306 sizeof(struct fq_flow),
1307 0, SLAB_HWCACHE_ALIGN, NULL);
1308 if (!fq_flow_cachep)
1309 return -ENOMEM;
1310
1311 ret = register_qdisc(&fq_qdisc_ops);
1312 if (ret)
1313 kmem_cache_destroy(fq_flow_cachep);
1314 return ret;
1315 }
1316
fq_module_exit(void)1317 static void __exit fq_module_exit(void)
1318 {
1319 unregister_qdisc(&fq_qdisc_ops);
1320 kmem_cache_destroy(fq_flow_cachep);
1321 }
1322
1323 module_init(fq_module_init)
1324 module_exit(fq_module_exit)
1325 MODULE_AUTHOR("Eric Dumazet");
1326 MODULE_LICENSE("GPL");
1327 MODULE_DESCRIPTION("Fair Queue Packet Scheduler");
1328