Root/target/linux/generic/patches-3.3/042-fq_codel-Fair-Queue-Codel-AQM.patch

1From f8cf19c19528a468cc0b9846c0328a94cccdc605 Mon Sep 17 00:00:00 2001
2From: Eric Dumazet <edumazet@google.com>
3Date: Fri, 11 May 2012 09:30:50 +0000
4Subject: [PATCH] fq_codel: Fair Queue Codel AQM
5
6commit 4b549a2ef4bef9965d97cbd992ba67930cd3e0fe upstream.
7
8Fair Queue Codel packet scheduler
9
10Principles :
11
12- Packets are classified (internal classifier or external) on flows.
13- This is a Stochastic model (as we use a hash, several flows might
14                              be hashed on same slot)
15- Each flow has a CoDel managed queue.
16- Flows are linked onto two (Round Robin) lists,
17  so that new flows have priority on old ones.
18
19- For a given flow, packets are not reordered (CoDel uses a FIFO)
20- head drops only.
21- ECN capability is on by default.
22- Very low memory footprint (64 bytes per flow)
23
24tc qdisc ... fq_codel [ limit PACKETS ] [ flows number ]
25                      [ target TIME ] [ interval TIME ] [ noecn ]
26                      [ quantum BYTES ]
27
28defaults : 1024 flows, 10240 packets limit, quantum : device MTU
29           target : 5ms (CoDel default)
30           interval : 100ms (CoDel default)
31
32Impressive results on load :
33
34class htb 1:1 root leaf 10: prio 0 quantum 1514 rate 200000Kbit ceil 200000Kbit burst 1475b/8 mpu 0b overhead 0b cburst 1475b/8 mpu 0b overhead 0b level 0
35 Sent 43304920109 bytes 33063109 pkt (dropped 0, overlimits 0 requeues 0)
36 rate 201691Kbit 28595pps backlog 0b 312p requeues 0
37 lended: 33063109 borrowed: 0 giants: 0
38 tokens: -912 ctokens: -912
39
40class fq_codel 10:1735 parent 10:
41 (dropped 1292, overlimits 0 requeues 0)
42 backlog 15140b 10p requeues 0
43  deficit 1514 count 1 lastcount 1 ldelay 7.1ms
44class fq_codel 10:4524 parent 10:
45 (dropped 1291, overlimits 0 requeues 0)
46 backlog 16654b 11p requeues 0
47  deficit 1514 count 1 lastcount 1 ldelay 7.1ms
48class fq_codel 10:4e74 parent 10:
49 (dropped 1290, overlimits 0 requeues 0)
50 backlog 6056b 4p requeues 0
51  deficit 1514 count 1 lastcount 1 ldelay 6.4ms dropping drop_next 92.0ms
52class fq_codel 10:628a parent 10:
53 (dropped 1289, overlimits 0 requeues 0)
54 backlog 7570b 5p requeues 0
55  deficit 1514 count 1 lastcount 1 ldelay 5.4ms dropping drop_next 90.9ms
56class fq_codel 10:a4b3 parent 10:
57 (dropped 302, overlimits 0 requeues 0)
58 backlog 16654b 11p requeues 0
59  deficit 1514 count 1 lastcount 1 ldelay 7.1ms
60class fq_codel 10:c3c2 parent 10:
61 (dropped 1284, overlimits 0 requeues 0)
62 backlog 13626b 9p requeues 0
63  deficit 1514 count 1 lastcount 1 ldelay 5.9ms
64class fq_codel 10:d331 parent 10:
65 (dropped 299, overlimits 0 requeues 0)
66 backlog 15140b 10p requeues 0
67  deficit 1514 count 1 lastcount 1 ldelay 7.0ms
68class fq_codel 10:d526 parent 10:
69 (dropped 12160, overlimits 0 requeues 0)
70 backlog 35870b 211p requeues 0
71  deficit 1508 count 12160 lastcount 1 ldelay 15.3ms dropping drop_next 247us
72class fq_codel 10:e2c6 parent 10:
73 (dropped 1288, overlimits 0 requeues 0)
74 backlog 15140b 10p requeues 0
75  deficit 1514 count 1 lastcount 1 ldelay 7.1ms
76class fq_codel 10:eab5 parent 10:
77 (dropped 1285, overlimits 0 requeues 0)
78 backlog 16654b 11p requeues 0
79  deficit 1514 count 1 lastcount 1 ldelay 5.9ms
80class fq_codel 10:f220 parent 10:
81 (dropped 1289, overlimits 0 requeues 0)
82 backlog 15140b 10p requeues 0
83  deficit 1514 count 1 lastcount 1 ldelay 7.1ms
84
85qdisc htb 1: root refcnt 6 r2q 10 default 1 direct_packets_stat 0 ver 3.17
86 Sent 43331086547 bytes 33092812 pkt (dropped 0, overlimits 66063544 requeues 71)
87 rate 201697Kbit 28602pps backlog 0b 260p requeues 71
88qdisc fq_codel 10: parent 1:1 limit 10240p flows 65536 target 5.0ms interval 100.0ms ecn
89 Sent 43331086547 bytes 33092812 pkt (dropped 949359, overlimits 0 requeues 0)
90 rate 201697Kbit 28602pps backlog 189352b 260p requeues 0
91  maxpacket 1514 drop_overlimit 0 new_flow_count 5582 ecn_mark 125593
92  new_flows_len 0 old_flows_len 11
93
94PING 172.30.42.18 (172.30.42.18) 56(84) bytes of data.
9564 bytes from 172.30.42.18: icmp_req=1 ttl=64 time=0.227 ms
9664 bytes from 172.30.42.18: icmp_req=2 ttl=64 time=0.165 ms
9764 bytes from 172.30.42.18: icmp_req=3 ttl=64 time=0.166 ms
9864 bytes from 172.30.42.18: icmp_req=4 ttl=64 time=0.151 ms
9964 bytes from 172.30.42.18: icmp_req=5 ttl=64 time=0.164 ms
10064 bytes from 172.30.42.18: icmp_req=6 ttl=64 time=0.172 ms
10164 bytes from 172.30.42.18: icmp_req=7 ttl=64 time=0.175 ms
10264 bytes from 172.30.42.18: icmp_req=8 ttl=64 time=0.183 ms
10364 bytes from 172.30.42.18: icmp_req=9 ttl=64 time=0.158 ms
10464 bytes from 172.30.42.18: icmp_req=10 ttl=64 time=0.200 ms
105
10610 packets transmitted, 10 received, 0% packet loss, time 8999ms
107rtt min/avg/max/mdev = 0.151/0.176/0.227/0.022 ms
108
109Much better than SFQ because of priority given to new flows, and fast
110path dirtying less cache lines.
111
112Signed-off-by: Eric Dumazet <edumazet@google.com>
113Signed-off-by: David S. Miller <davem@davemloft.net>
114---
115 include/linux/pkt_sched.h | 54 ++++
116 net/sched/Kconfig | 11 +
117 net/sched/Makefile | 1 +
118 net/sched/sch_fq_codel.c | 624 +++++++++++++++++++++++++++++++++++++++++++++
119 4 files changed, 690 insertions(+)
120 create mode 100644 net/sched/sch_fq_codel.c
121
122--- a/include/linux/pkt_sched.h
123+++ b/include/linux/pkt_sched.h
124@@ -659,4 +659,58 @@ struct tc_codel_xstats {
125     __u32 dropping; /* are we in dropping state ? */
126 };
127 
128+/* FQ_CODEL */
129+
130+enum {
131+ TCA_FQ_CODEL_UNSPEC,
132+ TCA_FQ_CODEL_TARGET,
133+ TCA_FQ_CODEL_LIMIT,
134+ TCA_FQ_CODEL_INTERVAL,
135+ TCA_FQ_CODEL_ECN,
136+ TCA_FQ_CODEL_FLOWS,
137+ TCA_FQ_CODEL_QUANTUM,
138+ __TCA_FQ_CODEL_MAX
139+};
140+
141+#define TCA_FQ_CODEL_MAX (__TCA_FQ_CODEL_MAX - 1)
142+
143+enum {
144+ TCA_FQ_CODEL_XSTATS_QDISC,
145+ TCA_FQ_CODEL_XSTATS_CLASS,
146+};
147+
148+struct tc_fq_codel_qd_stats {
149+ __u32 maxpacket; /* largest packet we've seen so far */
150+ __u32 drop_overlimit; /* number of time max qdisc
151+ * packet limit was hit
152+ */
153+ __u32 ecn_mark; /* number of packets we ECN marked
154+ * instead of being dropped
155+ */
156+ __u32 new_flow_count; /* number of time packets
157+ * created a 'new flow'
158+ */
159+ __u32 new_flows_len; /* count of flows in new list */
160+ __u32 old_flows_len; /* count of flows in old list */
161+};
162+
163+struct tc_fq_codel_cl_stats {
164+ __s32 deficit;
165+ __u32 ldelay; /* in-queue delay seen by most recently
166+ * dequeued packet
167+ */
168+ __u32 count;
169+ __u32 lastcount;
170+ __u32 dropping;
171+ __s32 drop_next;
172+};
173+
174+struct tc_fq_codel_xstats {
175+ __u32 type;
176+ union {
177+ struct tc_fq_codel_qd_stats qdisc_stats;
178+ struct tc_fq_codel_cl_stats class_stats;
179+ };
180+};
181+
182 #endif
183--- a/net/sched/Kconfig
184+++ b/net/sched/Kconfig
185@@ -261,6 +261,17 @@ config NET_SCH_CODEL
186 
187       If unsure, say N.
188 
189+config NET_SCH_FQ_CODEL
190+ tristate "Fair Queue Controlled Delay AQM (FQ_CODEL)"
191+ help
192+ Say Y here if you want to use the FQ Controlled Delay (FQ_CODEL)
193+ packet scheduling algorithm.
194+
195+ To compile this driver as a module, choose M here: the module
196+ will be called sch_fq_codel.
197+
198+ If unsure, say N.
199+
200 config NET_SCH_INGRESS
201     tristate "Ingress Qdisc"
202     depends on NET_CLS_ACT
203--- a/net/sched/Makefile
204+++ b/net/sched/Makefile
205@@ -37,6 +37,7 @@ obj-$(CONFIG_NET_SCH_MQPRIO) += sch_mqpr
206 obj-$(CONFIG_NET_SCH_CHOKE) += sch_choke.o
207 obj-$(CONFIG_NET_SCH_QFQ) += sch_qfq.o
208 obj-$(CONFIG_NET_SCH_CODEL) += sch_codel.o
209+obj-$(CONFIG_NET_SCH_FQ_CODEL) += sch_fq_codel.o
210 
211 obj-$(CONFIG_NET_CLS_U32) += cls_u32.o
212 obj-$(CONFIG_NET_CLS_ROUTE4) += cls_route.o
213--- /dev/null
214+++ b/net/sched/sch_fq_codel.c
215@@ -0,0 +1,624 @@
216+/*
217+ * Fair Queue CoDel discipline
218+ *
219+ * This program is free software; you can redistribute it and/or
220+ * modify it under the terms of the GNU General Public License
221+ * as published by the Free Software Foundation; either version
222+ * 2 of the License, or (at your option) any later version.
223+ *
224+ * Copyright (C) 2012 Eric Dumazet <edumazet@google.com>
225+ */
226+
227+#include <linux/module.h>
228+#include <linux/types.h>
229+#include <linux/kernel.h>
230+#include <linux/jiffies.h>
231+#include <linux/string.h>
232+#include <linux/in.h>
233+#include <linux/errno.h>
234+#include <linux/init.h>
235+#include <linux/skbuff.h>
236+#include <linux/jhash.h>
237+#include <linux/slab.h>
238+#include <linux/vmalloc.h>
239+#include <net/netlink.h>
240+#include <net/pkt_sched.h>
241+#include <net/flow_keys.h>
242+#include <net/codel.h>
243+
244+/* Fair Queue CoDel.
245+ *
246+ * Principles :
247+ * Packets are classified (internal classifier or external) on flows.
248+ * This is a Stochastic model (as we use a hash, several flows
249+ * might be hashed on same slot)
250+ * Each flow has a CoDel managed queue.
251+ * Flows are linked onto two (Round Robin) lists,
252+ * so that new flows have priority on old ones.
253+ *
254+ * For a given flow, packets are not reordered (CoDel uses a FIFO)
255+ * head drops only.
256+ * ECN capability is on by default.
257+ * Low memory footprint (64 bytes per flow)
258+ */
259+
260+struct fq_codel_flow {
261+ struct sk_buff *head;
262+ struct sk_buff *tail;
263+ struct list_head flowchain;
264+ int deficit;
265+ u32 dropped; /* number of drops (or ECN marks) on this flow */
266+ struct codel_vars cvars;
267+}; /* please try to keep this structure <= 64 bytes */
268+
269+struct fq_codel_sched_data {
270+ struct tcf_proto *filter_list; /* optional external classifier */
271+ struct fq_codel_flow *flows; /* Flows table [flows_cnt] */
272+ u32 *backlogs; /* backlog table [flows_cnt] */
273+ u32 flows_cnt; /* number of flows */
274+ u32 perturbation; /* hash perturbation */
275+ u32 quantum; /* psched_mtu(qdisc_dev(sch)); */
276+ struct codel_params cparams;
277+ struct codel_stats cstats;
278+ u32 drop_overlimit;
279+ u32 new_flow_count;
280+
281+ struct list_head new_flows; /* list of new flows */
282+ struct list_head old_flows; /* list of old flows */
283+};
284+
285+static unsigned int fq_codel_hash(const struct fq_codel_sched_data *q,
286+ const struct sk_buff *skb)
287+{
288+ struct flow_keys keys;
289+ unsigned int hash;
290+
291+ skb_flow_dissect(skb, &keys);
292+ hash = jhash_3words((__force u32)keys.dst,
293+ (__force u32)keys.src ^ keys.ip_proto,
294+ (__force u32)keys.ports, q->perturbation);
295+ return ((u64)hash * q->flows_cnt) >> 32;
296+}
297+
298+static unsigned int fq_codel_classify(struct sk_buff *skb, struct Qdisc *sch,
299+ int *qerr)
300+{
301+ struct fq_codel_sched_data *q = qdisc_priv(sch);
302+ struct tcf_result res;
303+ int result;
304+
305+ if (TC_H_MAJ(skb->priority) == sch->handle &&
306+ TC_H_MIN(skb->priority) > 0 &&
307+ TC_H_MIN(skb->priority) <= q->flows_cnt)
308+ return TC_H_MIN(skb->priority);
309+
310+ if (!q->filter_list)
311+ return fq_codel_hash(q, skb) + 1;
312+
313+ *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
314+ result = tc_classify(skb, q->filter_list, &res);
315+ if (result >= 0) {
316+#ifdef CONFIG_NET_CLS_ACT
317+ switch (result) {
318+ case TC_ACT_STOLEN:
319+ case TC_ACT_QUEUED:
320+ *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
321+ case TC_ACT_SHOT:
322+ return 0;
323+ }
324+#endif
325+ if (TC_H_MIN(res.classid) <= q->flows_cnt)
326+ return TC_H_MIN(res.classid);
327+ }
328+ return 0;
329+}
330+
331+/* helper functions : might be changed when/if skb use a standard list_head */
332+
333+/* remove one skb from head of slot queue */
334+static inline struct sk_buff *dequeue_head(struct fq_codel_flow *flow)
335+{
336+ struct sk_buff *skb = flow->head;
337+
338+ flow->head = skb->next;
339+ skb->next = NULL;
340+ return skb;
341+}
342+
343+/* add skb to flow queue (tail add) */
344+static inline void flow_queue_add(struct fq_codel_flow *flow,
345+ struct sk_buff *skb)
346+{
347+ if (flow->head == NULL)
348+ flow->head = skb;
349+ else
350+ flow->tail->next = skb;
351+ flow->tail = skb;
352+ skb->next = NULL;
353+}
354+
355+static unsigned int fq_codel_drop(struct Qdisc *sch)
356+{
357+ struct fq_codel_sched_data *q = qdisc_priv(sch);
358+ struct sk_buff *skb;
359+ unsigned int maxbacklog = 0, idx = 0, i, len;
360+ struct fq_codel_flow *flow;
361+
362+ /* Queue is full! Find the fat flow and drop packet from it.
363+ * This might sound expensive, but with 1024 flows, we scan
364+ * 4KB of memory, and we dont need to handle a complex tree
365+ * in fast path (packet queue/enqueue) with many cache misses.
366+ */
367+ for (i = 0; i < q->flows_cnt; i++) {
368+ if (q->backlogs[i] > maxbacklog) {
369+ maxbacklog = q->backlogs[i];
370+ idx = i;
371+ }
372+ }
373+ flow = &q->flows[idx];
374+ skb = dequeue_head(flow);
375+ len = qdisc_pkt_len(skb);
376+ q->backlogs[idx] -= len;
377+ kfree_skb(skb);
378+ sch->q.qlen--;
379+ sch->qstats.drops++;
380+ sch->qstats.backlog -= len;
381+ flow->dropped++;
382+ return idx;
383+}
384+
385+static int fq_codel_enqueue(struct sk_buff *skb, struct Qdisc *sch)
386+{
387+ struct fq_codel_sched_data *q = qdisc_priv(sch);
388+ unsigned int idx;
389+ struct fq_codel_flow *flow;
390+ int uninitialized_var(ret);
391+
392+ idx = fq_codel_classify(skb, sch, &ret);
393+ if (idx == 0) {
394+ if (ret & __NET_XMIT_BYPASS)
395+ sch->qstats.drops++;
396+ kfree_skb(skb);
397+ return ret;
398+ }
399+ idx--;
400+
401+ codel_set_enqueue_time(skb);
402+ flow = &q->flows[idx];
403+ flow_queue_add(flow, skb);
404+ q->backlogs[idx] += qdisc_pkt_len(skb);
405+ sch->qstats.backlog += qdisc_pkt_len(skb);
406+
407+ if (list_empty(&flow->flowchain)) {
408+ list_add_tail(&flow->flowchain, &q->new_flows);
409+ codel_vars_init(&flow->cvars);
410+ q->new_flow_count++;
411+ flow->deficit = q->quantum;
412+ flow->dropped = 0;
413+ }
414+ if (++sch->q.qlen < sch->limit)
415+ return NET_XMIT_SUCCESS;
416+
417+ q->drop_overlimit++;
418+ /* Return Congestion Notification only if we dropped a packet
419+ * from this flow.
420+ */
421+ if (fq_codel_drop(sch) == idx)
422+ return NET_XMIT_CN;
423+
424+ /* As we dropped a packet, better let upper stack know this */
425+ qdisc_tree_decrease_qlen(sch, 1);
426+ return NET_XMIT_SUCCESS;
427+}
428+
429+/* This is the specific function called from codel_dequeue()
430+ * to dequeue a packet from queue. Note: backlog is handled in
431+ * codel, we dont need to reduce it here.
432+ */
433+static struct sk_buff *dequeue(struct codel_vars *vars, struct Qdisc *sch)
434+{
435+ struct fq_codel_flow *flow;
436+ struct sk_buff *skb = NULL;
437+
438+ flow = container_of(vars, struct fq_codel_flow, cvars);
439+ if (flow->head) {
440+ skb = dequeue_head(flow);
441+ sch->qstats.backlog -= qdisc_pkt_len(skb);
442+ sch->q.qlen--;
443+ }
444+ return skb;
445+}
446+
447+static struct sk_buff *fq_codel_dequeue(struct Qdisc *sch)
448+{
449+ struct fq_codel_sched_data *q = qdisc_priv(sch);
450+ struct sk_buff *skb;
451+ struct fq_codel_flow *flow;
452+ struct list_head *head;
453+ u32 prev_drop_count, prev_ecn_mark;
454+
455+begin:
456+ head = &q->new_flows;
457+ if (list_empty(head)) {
458+ head = &q->old_flows;
459+ if (list_empty(head))
460+ return NULL;
461+ }
462+ flow = list_first_entry(head, struct fq_codel_flow, flowchain);
463+
464+ if (flow->deficit <= 0) {
465+ flow->deficit += q->quantum;
466+ list_move_tail(&flow->flowchain, &q->old_flows);
467+ goto begin;
468+ }
469+
470+ prev_drop_count = q->cstats.drop_count;
471+ prev_ecn_mark = q->cstats.ecn_mark;
472+
473+ skb = codel_dequeue(sch, &q->cparams, &flow->cvars, &q->cstats,
474+ dequeue, &q->backlogs[flow - q->flows]);
475+
476+ flow->dropped += q->cstats.drop_count - prev_drop_count;
477+ flow->dropped += q->cstats.ecn_mark - prev_ecn_mark;
478+
479+ if (!skb) {
480+ /* force a pass through old_flows to prevent starvation */
481+ if ((head == &q->new_flows) && !list_empty(&q->old_flows))
482+ list_move_tail(&flow->flowchain, &q->old_flows);
483+ else
484+ list_del_init(&flow->flowchain);
485+ goto begin;
486+ }
487+ qdisc_bstats_update(sch, skb);
488+ flow->deficit -= qdisc_pkt_len(skb);
489+ /* We cant call qdisc_tree_decrease_qlen() if our qlen is 0,
490+ * or HTB crashes. Defer it for next round.
491+ */
492+ if (q->cstats.drop_count && sch->q.qlen) {
493+ qdisc_tree_decrease_qlen(sch, q->cstats.drop_count);
494+ q->cstats.drop_count = 0;
495+ }
496+ return skb;
497+}
498+
499+static void fq_codel_reset(struct Qdisc *sch)
500+{
501+ struct sk_buff *skb;
502+
503+ while ((skb = fq_codel_dequeue(sch)) != NULL)
504+ kfree_skb(skb);
505+}
506+
507+static const struct nla_policy fq_codel_policy[TCA_FQ_CODEL_MAX + 1] = {
508+ [TCA_FQ_CODEL_TARGET] = { .type = NLA_U32 },
509+ [TCA_FQ_CODEL_LIMIT] = { .type = NLA_U32 },
510+ [TCA_FQ_CODEL_INTERVAL] = { .type = NLA_U32 },
511+ [TCA_FQ_CODEL_ECN] = { .type = NLA_U32 },
512+ [TCA_FQ_CODEL_FLOWS] = { .type = NLA_U32 },
513+ [TCA_FQ_CODEL_QUANTUM] = { .type = NLA_U32 },
514+};
515+
516+static int fq_codel_change(struct Qdisc *sch, struct nlattr *opt)
517+{
518+ struct fq_codel_sched_data *q = qdisc_priv(sch);
519+ struct nlattr *tb[TCA_FQ_CODEL_MAX + 1];
520+ int err;
521+
522+ if (!opt)
523+ return -EINVAL;
524+
525+ err = nla_parse_nested(tb, TCA_FQ_CODEL_MAX, opt, fq_codel_policy);
526+ if (err < 0)
527+ return err;
528+ if (tb[TCA_FQ_CODEL_FLOWS]) {
529+ if (q->flows)
530+ return -EINVAL;
531+ q->flows_cnt = nla_get_u32(tb[TCA_FQ_CODEL_FLOWS]);
532+ if (!q->flows_cnt ||
533+ q->flows_cnt > 65536)
534+ return -EINVAL;
535+ }
536+ sch_tree_lock(sch);
537+
538+ if (tb[TCA_FQ_CODEL_TARGET]) {
539+ u64 target = nla_get_u32(tb[TCA_FQ_CODEL_TARGET]);
540+
541+ q->cparams.target = (target * NSEC_PER_USEC) >> CODEL_SHIFT;
542+ }
543+
544+ if (tb[TCA_FQ_CODEL_INTERVAL]) {
545+ u64 interval = nla_get_u32(tb[TCA_FQ_CODEL_INTERVAL]);
546+
547+ q->cparams.interval = (interval * NSEC_PER_USEC) >> CODEL_SHIFT;
548+ }
549+
550+ if (tb[TCA_FQ_CODEL_LIMIT])
551+ sch->limit = nla_get_u32(tb[TCA_FQ_CODEL_LIMIT]);
552+
553+ if (tb[TCA_FQ_CODEL_ECN])
554+ q->cparams.ecn = !!nla_get_u32(tb[TCA_FQ_CODEL_ECN]);
555+
556+ if (tb[TCA_FQ_CODEL_QUANTUM])
557+ q->quantum = max(256U, nla_get_u32(tb[TCA_FQ_CODEL_QUANTUM]));
558+
559+ while (sch->q.qlen > sch->limit) {
560+ struct sk_buff *skb = fq_codel_dequeue(sch);
561+
562+ kfree_skb(skb);
563+ q->cstats.drop_count++;
564+ }
565+ qdisc_tree_decrease_qlen(sch, q->cstats.drop_count);
566+ q->cstats.drop_count = 0;
567+
568+ sch_tree_unlock(sch);
569+ return 0;
570+}
571+
572+static void *fq_codel_zalloc(size_t sz)
573+{
574+ void *ptr = kzalloc(sz, GFP_KERNEL | __GFP_NOWARN);
575+
576+ if (!ptr)
577+ ptr = vzalloc(sz);
578+ return ptr;
579+}
580+
581+static void fq_codel_free(void *addr)
582+{
583+ if (addr) {
584+ if (is_vmalloc_addr(addr))
585+ vfree(addr);
586+ else
587+ kfree(addr);
588+ }
589+}
590+
591+static void fq_codel_destroy(struct Qdisc *sch)
592+{
593+ struct fq_codel_sched_data *q = qdisc_priv(sch);
594+
595+ tcf_destroy_chain(&q->filter_list);
596+ fq_codel_free(q->backlogs);
597+ fq_codel_free(q->flows);
598+}
599+
600+static int fq_codel_init(struct Qdisc *sch, struct nlattr *opt)
601+{
602+ struct fq_codel_sched_data *q = qdisc_priv(sch);
603+ int i;
604+
605+ sch->limit = 10*1024;
606+ q->flows_cnt = 1024;
607+ q->quantum = psched_mtu(qdisc_dev(sch));
608+ q->perturbation = net_random();
609+ INIT_LIST_HEAD(&q->new_flows);
610+ INIT_LIST_HEAD(&q->old_flows);
611+ codel_params_init(&q->cparams);
612+ codel_stats_init(&q->cstats);
613+ q->cparams.ecn = true;
614+
615+ if (opt) {
616+ int err = fq_codel_change(sch, opt);
617+ if (err)
618+ return err;
619+ }
620+
621+ if (!q->flows) {
622+ q->flows = fq_codel_zalloc(q->flows_cnt *
623+ sizeof(struct fq_codel_flow));
624+ if (!q->flows)
625+ return -ENOMEM;
626+ q->backlogs = fq_codel_zalloc(q->flows_cnt * sizeof(u32));
627+ if (!q->backlogs) {
628+ fq_codel_free(q->flows);
629+ return -ENOMEM;
630+ }
631+ for (i = 0; i < q->flows_cnt; i++) {
632+ struct fq_codel_flow *flow = q->flows + i;
633+
634+ INIT_LIST_HEAD(&flow->flowchain);
635+ }
636+ }
637+ if (sch->limit >= 1)
638+ sch->flags |= TCQ_F_CAN_BYPASS;
639+ else
640+ sch->flags &= ~TCQ_F_CAN_BYPASS;
641+ return 0;
642+}
643+
644+static int fq_codel_dump(struct Qdisc *sch, struct sk_buff *skb)
645+{
646+ struct fq_codel_sched_data *q = qdisc_priv(sch);
647+ struct nlattr *opts;
648+
649+ opts = nla_nest_start(skb, TCA_OPTIONS);
650+ if (opts == NULL)
651+ goto nla_put_failure;
652+
653+ if (nla_put_u32(skb, TCA_FQ_CODEL_TARGET,
654+ codel_time_to_us(q->cparams.target)) ||
655+ nla_put_u32(skb, TCA_FQ_CODEL_LIMIT,
656+ sch->limit) ||
657+ nla_put_u32(skb, TCA_FQ_CODEL_INTERVAL,
658+ codel_time_to_us(q->cparams.interval)) ||
659+ nla_put_u32(skb, TCA_FQ_CODEL_ECN,
660+ q->cparams.ecn) ||
661+ nla_put_u32(skb, TCA_FQ_CODEL_QUANTUM,
662+ q->quantum) ||
663+ nla_put_u32(skb, TCA_FQ_CODEL_FLOWS,
664+ q->flows_cnt))
665+ goto nla_put_failure;
666+
667+ nla_nest_end(skb, opts);
668+ return skb->len;
669+
670+nla_put_failure:
671+ return -1;
672+}
673+
674+static int fq_codel_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
675+{
676+ struct fq_codel_sched_data *q = qdisc_priv(sch);
677+ struct tc_fq_codel_xstats st = {
678+ .type = TCA_FQ_CODEL_XSTATS_QDISC,
679+ .qdisc_stats.maxpacket = q->cstats.maxpacket,
680+ .qdisc_stats.drop_overlimit = q->drop_overlimit,
681+ .qdisc_stats.ecn_mark = q->cstats.ecn_mark,
682+ .qdisc_stats.new_flow_count = q->new_flow_count,
683+ };
684+ struct list_head *pos;
685+
686+ list_for_each(pos, &q->new_flows)
687+ st.qdisc_stats.new_flows_len++;
688+
689+ list_for_each(pos, &q->old_flows)
690+ st.qdisc_stats.old_flows_len++;
691+
692+ return gnet_stats_copy_app(d, &st, sizeof(st));
693+}
694+
695+static struct Qdisc *fq_codel_leaf(struct Qdisc *sch, unsigned long arg)
696+{
697+ return NULL;
698+}
699+
700+static unsigned long fq_codel_get(struct Qdisc *sch, u32 classid)
701+{
702+ return 0;
703+}
704+
705+static unsigned long fq_codel_bind(struct Qdisc *sch, unsigned long parent,
706+ u32 classid)
707+{
708+ /* we cannot bypass queue discipline anymore */
709+ sch->flags &= ~TCQ_F_CAN_BYPASS;
710+ return 0;
711+}
712+
713+static void fq_codel_put(struct Qdisc *q, unsigned long cl)
714+{
715+}
716+
717+static struct tcf_proto **fq_codel_find_tcf(struct Qdisc *sch, unsigned long cl)
718+{
719+ struct fq_codel_sched_data *q = qdisc_priv(sch);
720+
721+ if (cl)
722+ return NULL;
723+ return &q->filter_list;
724+}
725+
726+static int fq_codel_dump_class(struct Qdisc *sch, unsigned long cl,
727+ struct sk_buff *skb, struct tcmsg *tcm)
728+{
729+ tcm->tcm_handle |= TC_H_MIN(cl);
730+ return 0;
731+}
732+
733+static int fq_codel_dump_class_stats(struct Qdisc *sch, unsigned long cl,
734+ struct gnet_dump *d)
735+{
736+ struct fq_codel_sched_data *q = qdisc_priv(sch);
737+ u32 idx = cl - 1;
738+ struct gnet_stats_queue qs = { 0 };
739+ struct tc_fq_codel_xstats xstats;
740+
741+ if (idx < q->flows_cnt) {
742+ const struct fq_codel_flow *flow = &q->flows[idx];
743+ const struct sk_buff *skb = flow->head;
744+
745+ memset(&xstats, 0, sizeof(xstats));
746+ xstats.type = TCA_FQ_CODEL_XSTATS_CLASS;
747+ xstats.class_stats.deficit = flow->deficit;
748+ xstats.class_stats.ldelay =
749+ codel_time_to_us(flow->cvars.ldelay);
750+ xstats.class_stats.count = flow->cvars.count;
751+ xstats.class_stats.lastcount = flow->cvars.lastcount;
752+ xstats.class_stats.dropping = flow->cvars.dropping;
753+ if (flow->cvars.dropping) {
754+ codel_tdiff_t delta = flow->cvars.drop_next -
755+ codel_get_time();
756+
757+ xstats.class_stats.drop_next = (delta >= 0) ?
758+ codel_time_to_us(delta) :
759+ -codel_time_to_us(-delta);
760+ }
761+ while (skb) {
762+ qs.qlen++;
763+ skb = skb->next;
764+ }
765+ qs.backlog = q->backlogs[idx];
766+ qs.drops = flow->dropped;
767+ }
768+ if (gnet_stats_copy_queue(d, &qs) < 0)
769+ return -1;
770+ if (idx < q->flows_cnt)
771+ return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
772+ return 0;
773+}
774+
775+static void fq_codel_walk(struct Qdisc *sch, struct qdisc_walker *arg)
776+{
777+ struct fq_codel_sched_data *q = qdisc_priv(sch);
778+ unsigned int i;
779+
780+ if (arg->stop)
781+ return;
782+
783+ for (i = 0; i < q->flows_cnt; i++) {
784+ if (list_empty(&q->flows[i].flowchain) ||
785+ arg->count < arg->skip) {
786+ arg->count++;
787+ continue;
788+ }
789+ if (arg->fn(sch, i + 1, arg) < 0) {
790+ arg->stop = 1;
791+ break;
792+ }
793+ arg->count++;
794+ }
795+}
796+
797+static const struct Qdisc_class_ops fq_codel_class_ops = {
798+ .leaf = fq_codel_leaf,
799+ .get = fq_codel_get,
800+ .put = fq_codel_put,
801+ .tcf_chain = fq_codel_find_tcf,
802+ .bind_tcf = fq_codel_bind,
803+ .unbind_tcf = fq_codel_put,
804+ .dump = fq_codel_dump_class,
805+ .dump_stats = fq_codel_dump_class_stats,
806+ .walk = fq_codel_walk,
807+};
808+
809+static struct Qdisc_ops fq_codel_qdisc_ops __read_mostly = {
810+ .cl_ops = &fq_codel_class_ops,
811+ .id = "fq_codel",
812+ .priv_size = sizeof(struct fq_codel_sched_data),
813+ .enqueue = fq_codel_enqueue,
814+ .dequeue = fq_codel_dequeue,
815+ .peek = qdisc_peek_dequeued,
816+ .drop = fq_codel_drop,
817+ .init = fq_codel_init,
818+ .reset = fq_codel_reset,
819+ .destroy = fq_codel_destroy,
820+ .change = fq_codel_change,
821+ .dump = fq_codel_dump,
822+ .dump_stats = fq_codel_dump_stats,
823+ .owner = THIS_MODULE,
824+};
825+
826+static int __init fq_codel_module_init(void)
827+{
828+ return register_qdisc(&fq_codel_qdisc_ops);
829+}
830+
831+static void __exit fq_codel_module_exit(void)
832+{
833+ unregister_qdisc(&fq_codel_qdisc_ops);
834+}
835+
836+module_init(fq_codel_module_init)
837+module_exit(fq_codel_module_exit)
838+MODULE_AUTHOR("Eric Dumazet");
839+MODULE_LICENSE("GPL");
840

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