From f2f872f9272a79a1048877ea14c15576f46c225e Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 30 Jul 2013 17:55:08 -0700 Subject: netem: Introduce skb_orphan_partial() helper Commit 547669d483e578 ("tcp: xps: fix reordering issues") added unexpected reorders in case netem is used in a MQ setup for high performance test bed. ETH=eth0 tc qd del dev $ETH root 2>/dev/null tc qd add dev $ETH root handle 1: mq for i in `seq 1 32` do tc qd add dev $ETH parent 1:$i netem delay 100ms done As all tcp packets are orphaned by netem, TCP stack believes it can set skb->ooo_okay on all packets. In order to allow producers to send more packets, we want to keep sk_wmem_alloc from reaching sk_sndbuf limit. We can do that by accounting one byte per skb in netem queues, so that TCP stack is not fooled too much. Tested: With above MQ/netem setup, scaling number of concurrent flows gives linear results and no reorders/retransmits lpq83:~# for n in 1 10 20 30 40 50 60 70 80 90 100 do echo -n "n:$n " ; ./super_netperf $n -H 10.7.7.84; done n:1 198.46 n:10 2002.69 n:20 4000.98 n:30 6006.35 n:40 8020.93 n:50 10032.3 n:60 12081.9 n:70 13971.3 n:80 16009.7 n:90 17117.3 n:100 17425.5 Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/sched/sch_netem.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'net/sched') diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c index 82f6016d89ab..a6d788d45216 100644 --- a/net/sched/sch_netem.c +++ b/net/sched/sch_netem.c @@ -412,12 +412,9 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch) /* If a delay is expected, orphan the skb. (orphaning usually takes * place at TX completion time, so _before_ the link transit delay) - * Ideally, this orphaning should be done after the rate limiting - * module, because this breaks TCP Small Queue, and other mechanisms - * based on socket sk_wmem_alloc. */ if (q->latency || q->jitter) - skb_orphan(skb); + skb_orphan_partial(skb); /* * If we need to duplicate packet, then re-insert at top of the -- cgit v1.2.3 From afe4fd062416b158a8a8538b23adc1930a9b88dc Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 29 Aug 2013 15:49:55 -0700 Subject: pkt_sched: fq: Fair Queue packet scheduler - Uses perfect flow match (not stochastic hash like SFQ/FQ_codel) - Uses the new_flow/old_flow separation from FQ_codel - New flows get an initial credit allowing IW10 without added delay. - Special FIFO queue for high prio packets (no need for PRIO + FQ) - Uses a hash table of RB trees to locate the flows at enqueue() time - Smart on demand gc (at enqueue() time, RB tree lookup evicts old unused flows) - Dynamic memory allocations. - Designed to allow millions of concurrent flows per Qdisc. - Small memory footprint : ~8K per Qdisc, and 104 bytes per flow. - Single high resolution timer for throttled flows (if any). - One RB tree to link throttled flows. - Ability to have a max rate per flow. We might add a socket option to add per socket limitation. Attempts have been made to add TCP pacing in TCP stack, but this seems to add complex code to an already complex stack. TCP pacing is welcomed for flows having idle times, as the cwnd permits TCP stack to queue a possibly large number of packets. This removes the 'slow start after idle' choice, hitting badly large BDP flows, and applications delivering chunks of data as video streams. Nicely spaced packets : Here interface is 10Gbit, but flow bottleneck is ~20Mbit cwin is big, yet FQ avoids the typical bursts generated by TCP (as in netperf TCP_RR -- -r 100000,100000) 15:01:23.545279 IP A > B: . 78193:81089(2896) ack 65248 win 3125 15:01:23.545394 IP B > A: . ack 81089 win 3668 15:01:23.546488 IP A > B: . 81089:83985(2896) ack 65248 win 3125 15:01:23.546565 IP B > A: . ack 83985 win 3668 15:01:23.547713 IP A > B: . 83985:86881(2896) ack 65248 win 3125 15:01:23.547778 IP B > A: . ack 86881 win 3668 15:01:23.548911 IP A > B: . 86881:89777(2896) ack 65248 win 3125 15:01:23.548949 IP B > A: . ack 89777 win 3668 15:01:23.550116 IP A > B: . 89777:92673(2896) ack 65248 win 3125 15:01:23.550182 IP B > A: . ack 92673 win 3668 15:01:23.551333 IP A > B: . 92673:95569(2896) ack 65248 win 3125 15:01:23.551406 IP B > A: . ack 95569 win 3668 15:01:23.552539 IP A > B: . 95569:98465(2896) ack 65248 win 3125 15:01:23.552576 IP B > A: . ack 98465 win 3668 15:01:23.553756 IP A > B: . 98465:99913(1448) ack 65248 win 3125 15:01:23.554138 IP A > B: P 99913:100001(88) ack 65248 win 3125 15:01:23.554204 IP B > A: . ack 100001 win 3668 15:01:23.554234 IP B > A: . 65248:68144(2896) ack 100001 win 3668 15:01:23.555620 IP B > A: . 68144:71040(2896) ack 100001 win 3668 15:01:23.557005 IP B > A: . 71040:73936(2896) ack 100001 win 3668 15:01:23.558390 IP B > A: . 73936:76832(2896) ack 100001 win 3668 15:01:23.559773 IP B > A: . 76832:79728(2896) ack 100001 win 3668 15:01:23.561158 IP B > A: . 79728:82624(2896) ack 100001 win 3668 15:01:23.562543 IP B > A: . 82624:85520(2896) ack 100001 win 3668 15:01:23.563928 IP B > A: . 85520:88416(2896) ack 100001 win 3668 15:01:23.565313 IP B > A: . 88416:91312(2896) ack 100001 win 3668 15:01:23.566698 IP B > A: . 91312:94208(2896) ack 100001 win 3668 15:01:23.568083 IP B > A: . 94208:97104(2896) ack 100001 win 3668 15:01:23.569467 IP B > A: . 97104:100000(2896) ack 100001 win 3668 15:01:23.570852 IP B > A: . 100000:102896(2896) ack 100001 win 3668 15:01:23.572237 IP B > A: . 102896:105792(2896) ack 100001 win 3668 15:01:23.573639 IP B > A: . 105792:108688(2896) ack 100001 win 3668 15:01:23.575024 IP B > A: . 108688:111584(2896) ack 100001 win 3668 15:01:23.576408 IP B > A: . 111584:114480(2896) ack 100001 win 3668 15:01:23.577793 IP B > A: . 114480:117376(2896) ack 100001 win 3668 TCP timestamps show that most packets from B were queued in the same ms timeframe (TSval 1159799{3,4}), but FQ managed to send them right in time to avoid a big burst. In slow start or steady state, very few packets are throttled [1] FQ gets a bunch of tunables as : limit : max number of packets on whole Qdisc (default 10000) flow_limit : max number of packets per flow (default 100) quantum : the credit per RR round (default is 2 MTU) initial_quantum : initial credit for new flows (default is 10 MTU) maxrate : max per flow rate (default : unlimited) buckets : number of RB trees (default : 1024) in hash table. (consumes 8 bytes per bucket) [no]pacing : disable/enable pacing (default is enable) All of them can be changed on a live qdisc. $ tc qd add dev eth0 root fq help Usage: ... fq [ limit PACKETS ] [ flow_limit PACKETS ] [ quantum BYTES ] [ initial_quantum BYTES ] [ maxrate RATE ] [ buckets NUMBER ] [ [no]pacing ] $ tc -s -d qd qdisc fq 8002: dev eth0 root refcnt 32 limit 10000p flow_limit 100p buckets 256 quantum 3028 initial_quantum 15140 Sent 216532416 bytes 148395 pkt (dropped 0, overlimits 0 requeues 14) backlog 0b 0p requeues 14 511 flows, 511 inactive, 0 throttled 110 gc, 0 highprio, 0 retrans, 1143 throttled, 0 flows_plimit [1] Except if initial srtt is overestimated, as if using cached srtt in tcp metrics. We'll provide a fix for this issue. Signed-off-by: Eric Dumazet Cc: Yuchung Cheng Cc: Neal Cardwell Signed-off-by: David S. Miller --- net/sched/Kconfig | 14 + net/sched/Makefile | 1 + net/sched/sch_fq.c | 792 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 807 insertions(+) create mode 100644 net/sched/sch_fq.c (limited to 'net/sched') diff --git a/net/sched/Kconfig b/net/sched/Kconfig index 235e01acac51..c03a32a0418e 100644 --- a/net/sched/Kconfig +++ b/net/sched/Kconfig @@ -272,6 +272,20 @@ config NET_SCH_FQ_CODEL If unsure, say N. +config NET_SCH_FQ + tristate "Fair Queue" + help + Say Y here if you want to use the FQ packet scheduling algorithm. + + FQ does flow separation, and is able to respect pacing requirements + set by TCP stack into sk->sk_pacing_rate (for localy generated + traffic) + + To compile this driver as a module, choose M here: the module + will be called sch_fq. + + If unsure, say N. + config NET_SCH_INGRESS tristate "Ingress Qdisc" depends on NET_CLS_ACT diff --git a/net/sched/Makefile b/net/sched/Makefile index 978cbf004e80..e5f9abe9a5db 100644 --- a/net/sched/Makefile +++ b/net/sched/Makefile @@ -39,6 +39,7 @@ obj-$(CONFIG_NET_SCH_CHOKE) += sch_choke.o obj-$(CONFIG_NET_SCH_QFQ) += sch_qfq.o obj-$(CONFIG_NET_SCH_CODEL) += sch_codel.o obj-$(CONFIG_NET_SCH_FQ_CODEL) += sch_fq_codel.o +obj-$(CONFIG_NET_SCH_FQ) += sch_fq.o obj-$(CONFIG_NET_CLS_U32) += cls_u32.o obj-$(CONFIG_NET_CLS_ROUTE4) += cls_route.o diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c new file mode 100644 index 000000000000..91ceca7bcb52 --- /dev/null +++ b/net/sched/sch_fq.c @@ -0,0 +1,792 @@ +/* + * net/sched/sch_fq.c Fair Queue Packet Scheduler (per flow pacing) + * + * Copyright (C) 2013 Eric Dumazet + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * Meant to be mostly used for localy generated traffic : + * Fast classification depends on skb->sk being set before reaching us. + * If not, (router workload), we use rxhash as fallback, with 32 bits wide hash. + * All packets belonging to a socket are considered as a 'flow'. + * + * Flows are dynamically allocated and stored in a hash table of RB trees + * They are also part of one Round Robin 'queues' (new or old flows) + * + * Burst avoidance (aka pacing) capability : + * + * Transport (eg TCP) can set in sk->sk_pacing_rate a rate, enqueue a + * bunch of packets, and this packet scheduler adds delay between + * packets to respect rate limitation. + * + * enqueue() : + * - lookup one RB tree (out of 1024 or more) to find the flow. + * If non existent flow, create it, add it to the tree. + * Add skb to the per flow list of skb (fifo). + * - Use a special fifo for high prio packets + * + * dequeue() : serves flows in Round Robin + * Note : When a flow becomes empty, we do not immediately remove it from + * rb trees, for performance reasons (its expected to send additional packets, + * or SLAB cache will reuse socket for another flow) + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * Per flow structure, dynamically allocated + */ +struct fq_flow { + struct sk_buff *head; /* list of skbs for this flow : first skb */ + union { + struct sk_buff *tail; /* last skb in the list */ + unsigned long age; /* jiffies when flow was emptied, for gc */ + }; + struct rb_node fq_node; /* anchor in fq_root[] trees */ + struct sock *sk; + int qlen; /* number of packets in flow queue */ + int credit; + u32 socket_hash; /* sk_hash */ + struct fq_flow *next; /* next pointer in RR lists, or &detached */ + + struct rb_node rate_node; /* anchor in q->delayed tree */ + u64 time_next_packet; +}; + +struct fq_flow_head { + struct fq_flow *first; + struct fq_flow *last; +}; + +struct fq_sched_data { + struct fq_flow_head new_flows; + + struct fq_flow_head old_flows; + + struct rb_root delayed; /* for rate limited flows */ + u64 time_next_delayed_flow; + + struct fq_flow internal; /* for non classified or high prio packets */ + u32 quantum; + u32 initial_quantum; + u32 flow_default_rate;/* rate per flow : bytes per second */ + u32 flow_max_rate; /* optional max rate per flow */ + u32 flow_plimit; /* max packets per flow */ + struct rb_root *fq_root; + u8 rate_enable; + u8 fq_trees_log; + + u32 flows; + u32 inactive_flows; + u32 throttled_flows; + + u64 stat_gc_flows; + u64 stat_internal_packets; + u64 stat_tcp_retrans; + u64 stat_throttled; + u64 stat_flows_plimit; + u64 stat_pkts_too_long; + u64 stat_allocation_errors; + struct qdisc_watchdog watchdog; +}; + +/* special value to mark a detached flow (not on old/new list) */ +static struct fq_flow detached, throttled; + +static void fq_flow_set_detached(struct fq_flow *f) +{ + f->next = &detached; +} + +static bool fq_flow_is_detached(const struct fq_flow *f) +{ + return f->next == &detached; +} + +static void fq_flow_set_throttled(struct fq_sched_data *q, struct fq_flow *f) +{ + struct rb_node **p = &q->delayed.rb_node, *parent = NULL; + + while (*p) { + struct fq_flow *aux; + + parent = *p; + aux = container_of(parent, struct fq_flow, rate_node); + if (f->time_next_packet >= aux->time_next_packet) + p = &parent->rb_right; + else + p = &parent->rb_left; + } + rb_link_node(&f->rate_node, parent, p); + rb_insert_color(&f->rate_node, &q->delayed); + q->throttled_flows++; + q->stat_throttled++; + + f->next = &throttled; + if (q->time_next_delayed_flow > f->time_next_packet) + q->time_next_delayed_flow = f->time_next_packet; +} + + +static struct kmem_cache *fq_flow_cachep __read_mostly; + +static void fq_flow_add_tail(struct fq_flow_head *head, struct fq_flow *flow) +{ + if (head->first) + head->last->next = flow; + else + head->first = flow; + head->last = flow; + flow->next = NULL; +} + +/* limit number of collected flows per round */ +#define FQ_GC_MAX 8 +#define FQ_GC_AGE (3*HZ) + +static bool fq_gc_candidate(const struct fq_flow *f) +{ + return fq_flow_is_detached(f) && + time_after(jiffies, f->age + FQ_GC_AGE); +} + +static void fq_gc(struct fq_sched_data *q, + struct rb_root *root, + struct sock *sk) +{ + struct fq_flow *f, *tofree[FQ_GC_MAX]; + struct rb_node **p, *parent; + int fcnt = 0; + + p = &root->rb_node; + parent = NULL; + while (*p) { + parent = *p; + + f = container_of(parent, struct fq_flow, fq_node); + if (f->sk == sk) + break; + + if (fq_gc_candidate(f)) { + tofree[fcnt++] = f; + if (fcnt == FQ_GC_MAX) + break; + } + + if (f->sk > sk) + p = &parent->rb_right; + else + p = &parent->rb_left; + } + + q->flows -= fcnt; + q->inactive_flows -= fcnt; + q->stat_gc_flows += fcnt; + while (fcnt) { + struct fq_flow *f = tofree[--fcnt]; + + rb_erase(&f->fq_node, root); + kmem_cache_free(fq_flow_cachep, f); + } +} + +static const u8 prio2band[TC_PRIO_MAX + 1] = { + 1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1 +}; + +static struct fq_flow *fq_classify(struct sk_buff *skb, struct fq_sched_data *q) +{ + struct rb_node **p, *parent; + struct sock *sk = skb->sk; + struct rb_root *root; + struct fq_flow *f; + int band; + + /* warning: no starvation prevention... */ + band = prio2band[skb->priority & TC_PRIO_MAX]; + if (unlikely(band == 0)) + return &q->internal; + + if (unlikely(!sk)) { + /* By forcing low order bit to 1, we make sure to not + * collide with a local flow (socket pointers are word aligned) + */ + sk = (struct sock *)(skb_get_rxhash(skb) | 1L); + } + + root = &q->fq_root[hash_32((u32)(long)sk, q->fq_trees_log)]; + + if (q->flows >= (2U << q->fq_trees_log) && + q->inactive_flows > q->flows/2) + fq_gc(q, root, sk); + + p = &root->rb_node; + parent = NULL; + while (*p) { + parent = *p; + + f = container_of(parent, struct fq_flow, fq_node); + if (f->sk == sk) { + /* socket might have been reallocated, so check + * if its sk_hash is the same. + * It not, we need to refill credit with + * initial quantum + */ + if (unlikely(skb->sk && + f->socket_hash != sk->sk_hash)) { + f->credit = q->initial_quantum; + f->socket_hash = sk->sk_hash; + } + return f; + } + if (f->sk > sk) + p = &parent->rb_right; + else + p = &parent->rb_left; + } + + f = kmem_cache_zalloc(fq_flow_cachep, GFP_ATOMIC | __GFP_NOWARN); + if (unlikely(!f)) { + q->stat_allocation_errors++; + return &q->internal; + } + fq_flow_set_detached(f); + f->sk = sk; + if (skb->sk) + f->socket_hash = sk->sk_hash; + f->credit = q->initial_quantum; + + rb_link_node(&f->fq_node, parent, p); + rb_insert_color(&f->fq_node, root); + + q->flows++; + q->inactive_flows++; + return f; +} + + +/* remove one skb from head of flow queue */ +static struct sk_buff *fq_dequeue_head(struct fq_flow *flow) +{ + struct sk_buff *skb = flow->head; + + if (skb) { + flow->head = skb->next; + skb->next = NULL; + flow->qlen--; + } + return skb; +} + +/* We might add in the future detection of retransmits + * For the time being, just return false + */ +static bool skb_is_retransmit(struct sk_buff *skb) +{ + return false; +} + +/* add skb to flow queue + * flow queue is a linked list, kind of FIFO, except for TCP retransmits + * We special case tcp retransmits to be transmitted before other packets. + * We rely on fact that TCP retransmits are unlikely, so we do not waste + * a separate queue or a pointer. + * head-> [retrans pkt 1] + * [retrans pkt 2] + * [ normal pkt 1] + * [ normal pkt 2] + * [ normal pkt 3] + * tail-> [ normal pkt 4] + */ +static void flow_queue_add(struct fq_flow *flow, struct sk_buff *skb) +{ + struct sk_buff *prev, *head = flow->head; + + skb->next = NULL; + if (!head) { + flow->head = skb; + flow->tail = skb; + return; + } + if (likely(!skb_is_retransmit(skb))) { + flow->tail->next = skb; + flow->tail = skb; + return; + } + + /* This skb is a tcp retransmit, + * find the last retrans packet in the queue + */ + prev = NULL; + while (skb_is_retransmit(head)) { + prev = head; + head = head->next; + if (!head) + break; + } + if (!prev) { /* no rtx packet in queue, become the new head */ + skb->next = flow->head; + flow->head = skb; + } else { + if (prev == flow->tail) + flow->tail = skb; + else + skb->next = prev->next; + prev->next = skb; + } +} + +static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch) +{ + struct fq_sched_data *q = qdisc_priv(sch); + struct fq_flow *f; + + if (unlikely(sch->q.qlen >= sch->limit)) + return qdisc_drop(skb, sch); + + f = fq_classify(skb, q); + if (unlikely(f->qlen >= q->flow_plimit && f != &q->internal)) { + q->stat_flows_plimit++; + return qdisc_drop(skb, sch); + } + + f->qlen++; + flow_queue_add(f, skb); + if (skb_is_retransmit(skb)) + q->stat_tcp_retrans++; + sch->qstats.backlog += qdisc_pkt_len(skb); + if (fq_flow_is_detached(f)) { + fq_flow_add_tail(&q->new_flows, f); + if (q->quantum > f->credit) + f->credit = q->quantum; + q->inactive_flows--; + qdisc_unthrottled(sch); + } + if (unlikely(f == &q->internal)) { + q->stat_internal_packets++; + qdisc_unthrottled(sch); + } + sch->q.qlen++; + + return NET_XMIT_SUCCESS; +} + +static void fq_check_throttled(struct fq_sched_data *q, u64 now) +{ + struct rb_node *p; + + if (q->time_next_delayed_flow > now) + return; + + q->time_next_delayed_flow = ~0ULL; + while ((p = rb_first(&q->delayed)) != NULL) { + struct fq_flow *f = container_of(p, struct fq_flow, rate_node); + + if (f->time_next_packet > now) { + q->time_next_delayed_flow = f->time_next_packet; + break; + } + rb_erase(p, &q->delayed); + q->throttled_flows--; + fq_flow_add_tail(&q->old_flows, f); + } +} + +static struct sk_buff *fq_dequeue(struct Qdisc *sch) +{ + struct fq_sched_data *q = qdisc_priv(sch); + u64 now = ktime_to_ns(ktime_get()); + struct fq_flow_head *head; + struct sk_buff *skb; + struct fq_flow *f; + + skb = fq_dequeue_head(&q->internal); + if (skb) + goto out; + fq_check_throttled(q, now); +begin: + head = &q->new_flows; + if (!head->first) { + head = &q->old_flows; + if (!head->first) { + if (q->time_next_delayed_flow != ~0ULL) + qdisc_watchdog_schedule_ns(&q->watchdog, + q->time_next_delayed_flow); + return NULL; + } + } + f = head->first; + + if (f->credit <= 0) { + f->credit += q->quantum; + head->first = f->next; + fq_flow_add_tail(&q->old_flows, f); + goto begin; + } + + if (unlikely(f->head && now < f->time_next_packet)) { + head->first = f->next; + fq_flow_set_throttled(q, f); + goto begin; + } + + skb = fq_dequeue_head(f); + if (!skb) { + head->first = f->next; + /* force a pass through old_flows to prevent starvation */ + if ((head == &q->new_flows) && q->old_flows.first) { + fq_flow_add_tail(&q->old_flows, f); + } else { + fq_flow_set_detached(f); + f->age = jiffies; + q->inactive_flows++; + } + goto begin; + } + f->time_next_packet = now; + f->credit -= qdisc_pkt_len(skb); + + if (f->credit <= 0 && + q->rate_enable && + skb->sk && skb->sk->sk_state != TCP_TIME_WAIT) { + u32 rate = skb->sk->sk_pacing_rate ?: q->flow_default_rate; + + rate = min(rate, q->flow_max_rate); + if (rate) { + u64 len = (u64)qdisc_pkt_len(skb) * NSEC_PER_SEC; + + do_div(len, rate); + /* Since socket rate can change later, + * clamp the delay to 125 ms. + * TODO: maybe segment the too big skb, as in commit + * e43ac79a4bc ("sch_tbf: segment too big GSO packets") + */ + if (unlikely(len > 125 * NSEC_PER_MSEC)) { + len = 125 * NSEC_PER_MSEC; + q->stat_pkts_too_long++; + } + + f->time_next_packet = now + len; + } + } +out: + prefetch(&skb->end); + sch->qstats.backlog -= qdisc_pkt_len(skb); + qdisc_bstats_update(sch, skb); + sch->q.qlen--; + qdisc_unthrottled(sch); + return skb; +} + +static void fq_reset(struct Qdisc *sch) +{ + struct sk_buff *skb; + + while ((skb = fq_dequeue(sch)) != NULL) + kfree_skb(skb); +} + +static void fq_rehash(struct fq_sched_data *q, + struct rb_root *old_array, u32 old_log, + struct rb_root *new_array, u32 new_log) +{ + struct rb_node *op, **np, *parent; + struct rb_root *oroot, *nroot; + struct fq_flow *of, *nf; + int fcnt = 0; + u32 idx; + + for (idx = 0; idx < (1U << old_log); idx++) { + oroot = &old_array[idx]; + while ((op = rb_first(oroot)) != NULL) { + rb_erase(op, oroot); + of = container_of(op, struct fq_flow, fq_node); + if (fq_gc_candidate(of)) { + fcnt++; + kmem_cache_free(fq_flow_cachep, of); + continue; + } + nroot = &new_array[hash_32((u32)(long)of->sk, new_log)]; + + np = &nroot->rb_node; + parent = NULL; + while (*np) { + parent = *np; + + nf = container_of(parent, struct fq_flow, fq_node); + BUG_ON(nf->sk == of->sk); + + if (nf->sk > of->sk) + np = &parent->rb_right; + else + np = &parent->rb_left; + } + + rb_link_node(&of->fq_node, parent, np); + rb_insert_color(&of->fq_node, nroot); + } + } + q->flows -= fcnt; + q->inactive_flows -= fcnt; + q->stat_gc_flows += fcnt; +} + +static int fq_resize(struct fq_sched_data *q, u32 log) +{ + struct rb_root *array; + u32 idx; + + if (q->fq_root && log == q->fq_trees_log) + return 0; + + array = kmalloc(sizeof(struct rb_root) << log, GFP_KERNEL); + if (!array) + return -ENOMEM; + + for (idx = 0; idx < (1U << log); idx++) + array[idx] = RB_ROOT; + + if (q->fq_root) { + fq_rehash(q, q->fq_root, q->fq_trees_log, array, log); + kfree(q->fq_root); + } + q->fq_root = array; + q->fq_trees_log = log; + + return 0; +} + +static const struct nla_policy fq_policy[TCA_FQ_MAX + 1] = { + [TCA_FQ_PLIMIT] = { .type = NLA_U32 }, + [TCA_FQ_FLOW_PLIMIT] = { .type = NLA_U32 }, + [TCA_FQ_QUANTUM] = { .type = NLA_U32 }, + [TCA_FQ_INITIAL_QUANTUM] = { .type = NLA_U32 }, + [TCA_FQ_RATE_ENABLE] = { .type = NLA_U32 }, + [TCA_FQ_FLOW_DEFAULT_RATE] = { .type = NLA_U32 }, + [TCA_FQ_FLOW_MAX_RATE] = { .type = NLA_U32 }, + [TCA_FQ_BUCKETS_LOG] = { .type = NLA_U32 }, +}; + +static int fq_change(struct Qdisc *sch, struct nlattr *opt) +{ + struct fq_sched_data *q = qdisc_priv(sch); + struct nlattr *tb[TCA_FQ_MAX + 1]; + int err, drop_count = 0; + u32 fq_log; + + if (!opt) + return -EINVAL; + + err = nla_parse_nested(tb, TCA_FQ_MAX, opt, fq_policy); + if (err < 0) + return err; + + sch_tree_lock(sch); + + fq_log = q->fq_trees_log; + + if (tb[TCA_FQ_BUCKETS_LOG]) { + u32 nval = nla_get_u32(tb[TCA_FQ_BUCKETS_LOG]); + + if (nval >= 1 && nval <= ilog2(256*1024)) + fq_log = nval; + else + err = -EINVAL; + } + if (tb[TCA_FQ_PLIMIT]) + sch->limit = nla_get_u32(tb[TCA_FQ_PLIMIT]); + + if (tb[TCA_FQ_FLOW_PLIMIT]) + q->flow_plimit = nla_get_u32(tb[TCA_FQ_FLOW_PLIMIT]); + + if (tb[TCA_FQ_QUANTUM]) + q->quantum = nla_get_u32(tb[TCA_FQ_QUANTUM]); + + if (tb[TCA_FQ_INITIAL_QUANTUM]) + q->quantum = nla_get_u32(tb[TCA_FQ_INITIAL_QUANTUM]); + + if (tb[TCA_FQ_FLOW_DEFAULT_RATE]) + q->flow_default_rate = nla_get_u32(tb[TCA_FQ_FLOW_DEFAULT_RATE]); + + if (tb[TCA_FQ_FLOW_MAX_RATE]) + q->flow_max_rate = nla_get_u32(tb[TCA_FQ_FLOW_MAX_RATE]); + + if (tb[TCA_FQ_RATE_ENABLE]) { + u32 enable = nla_get_u32(tb[TCA_FQ_RATE_ENABLE]); + + if (enable <= 1) + q->rate_enable = enable; + else + err = -EINVAL; + } + + if (!err) + err = fq_resize(q, fq_log); + + while (sch->q.qlen > sch->limit) { + struct sk_buff *skb = fq_dequeue(sch); + + kfree_skb(skb); + drop_count++; + } + qdisc_tree_decrease_qlen(sch, drop_count); + + sch_tree_unlock(sch); + return err; +} + +static void fq_destroy(struct Qdisc *sch) +{ + struct fq_sched_data *q = qdisc_priv(sch); + struct rb_root *root; + struct rb_node *p; + unsigned int idx; + + if (q->fq_root) { + for (idx = 0; idx < (1U << q->fq_trees_log); idx++) { + root = &q->fq_root[idx]; + while ((p = rb_first(root)) != NULL) { + rb_erase(p, root); + kmem_cache_free(fq_flow_cachep, + container_of(p, struct fq_flow, fq_node)); + } + } + kfree(q->fq_root); + } + qdisc_watchdog_cancel(&q->watchdog); +} + +static int fq_init(struct Qdisc *sch, struct nlattr *opt) +{ + struct fq_sched_data *q = qdisc_priv(sch); + int err; + + sch->limit = 10000; + q->flow_plimit = 100; + q->quantum = 2 * psched_mtu(qdisc_dev(sch)); + q->initial_quantum = 10 * psched_mtu(qdisc_dev(sch)); + q->flow_default_rate = 0; + q->flow_max_rate = ~0U; + q->rate_enable = 1; + q->new_flows.first = NULL; + q->old_flows.first = NULL; + q->delayed = RB_ROOT; + q->fq_root = NULL; + q->fq_trees_log = ilog2(1024); + qdisc_watchdog_init(&q->watchdog, sch); + + if (opt) + err = fq_change(sch, opt); + else + err = fq_resize(q, q->fq_trees_log); + + return err; +} + +static int fq_dump(struct Qdisc *sch, struct sk_buff *skb) +{ + struct fq_sched_data *q = qdisc_priv(sch); + struct nlattr *opts; + + opts = nla_nest_start(skb, TCA_OPTIONS); + if (opts == NULL) + goto nla_put_failure; + + if (nla_put_u32(skb, TCA_FQ_PLIMIT, sch->limit) || + nla_put_u32(skb, TCA_FQ_FLOW_PLIMIT, q->flow_plimit) || + nla_put_u32(skb, TCA_FQ_QUANTUM, q->quantum) || + nla_put_u32(skb, TCA_FQ_INITIAL_QUANTUM, q->initial_quantum) || + nla_put_u32(skb, TCA_FQ_RATE_ENABLE, q->rate_enable) || + nla_put_u32(skb, TCA_FQ_FLOW_DEFAULT_RATE, q->flow_default_rate) || + nla_put_u32(skb, TCA_FQ_FLOW_MAX_RATE, q->flow_max_rate) || + nla_put_u32(skb, TCA_FQ_BUCKETS_LOG, q->fq_trees_log)) + goto nla_put_failure; + + nla_nest_end(skb, opts); + return skb->len; + +nla_put_failure: + return -1; +} + +static int fq_dump_stats(struct Qdisc *sch, struct gnet_dump *d) +{ + struct fq_sched_data *q = qdisc_priv(sch); + u64 now = ktime_to_ns(ktime_get()); + struct tc_fq_qd_stats st = { + .gc_flows = q->stat_gc_flows, + .highprio_packets = q->stat_internal_packets, + .tcp_retrans = q->stat_tcp_retrans, + .throttled = q->stat_throttled, + .flows_plimit = q->stat_flows_plimit, + .pkts_too_long = q->stat_pkts_too_long, + .allocation_errors = q->stat_allocation_errors, + .flows = q->flows, + .inactive_flows = q->inactive_flows, + .throttled_flows = q->throttled_flows, + .time_next_delayed_flow = q->time_next_delayed_flow - now, + }; + + return gnet_stats_copy_app(d, &st, sizeof(st)); +} + +static struct Qdisc_ops fq_qdisc_ops __read_mostly = { + .id = "fq", + .priv_size = sizeof(struct fq_sched_data), + + .enqueue = fq_enqueue, + .dequeue = fq_dequeue, + .peek = qdisc_peek_dequeued, + .init = fq_init, + .reset = fq_reset, + .destroy = fq_destroy, + .change = fq_change, + .dump = fq_dump, + .dump_stats = fq_dump_stats, + .owner = THIS_MODULE, +}; + +static int __init fq_module_init(void) +{ + int ret; + + fq_flow_cachep = kmem_cache_create("fq_flow_cache", + sizeof(struct fq_flow), + 0, 0, NULL); + if (!fq_flow_cachep) + return -ENOMEM; + + ret = register_qdisc(&fq_qdisc_ops); + if (ret) + kmem_cache_destroy(fq_flow_cachep); + return ret; +} + +static void __exit fq_module_exit(void) +{ + unregister_qdisc(&fq_qdisc_ops); + kmem_cache_destroy(fq_flow_cachep); +} + +module_init(fq_module_init) +module_exit(fq_module_exit) +MODULE_AUTHOR("Eric Dumazet"); +MODULE_LICENSE("GPL"); -- cgit v1.2.3 From 08f89b981b0e6b46058dae2957241d4099129521 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 30 Aug 2013 09:46:43 -0700 Subject: pkt_sched: fq: prefetch() fix kbuild bot reported following m68k build error : net/sched/sch_fq.c: In function 'fq_dequeue': >> net/sched/sch_fq.c:491:2: error: implicit declaration of function 'prefetch' [-Werror=implicit-function-declaration] cc1: some warnings being treated as errors While we are fixing this, move this prefetch() call a bit earlier. Reported-by: Wu Fengguang Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/sched/sch_fq.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'net/sched') diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c index 91ceca7bcb52..32ad015ee8ce 100644 --- a/net/sched/sch_fq.c +++ b/net/sched/sch_fq.c @@ -46,6 +46,7 @@ #include #include #include +#include #include #include #include @@ -461,6 +462,7 @@ begin: } goto begin; } + prefetch(&skb->end); f->time_next_packet = now; f->credit -= qdisc_pkt_len(skb); @@ -488,7 +490,6 @@ begin: } } out: - prefetch(&skb->end); sch->qstats.backlog -= qdisc_pkt_len(skb); qdisc_bstats_update(sch, skb); sch->q.qlen--; -- cgit v1.2.3 From 6da7c8fcbcbdb50ec68c61b40d554c74850fdb91 Mon Sep 17 00:00:00 2001 From: stephen hemminger Date: Tue, 27 Aug 2013 16:19:08 -0700 Subject: qdisc: allow setting default queuing discipline By default, the pfifo_fast queue discipline has been used by default for all devices. But we have better choices now. This patch allow setting the default queueing discipline with sysctl. This allows easy use of better queueing disciplines on all devices without having to use tc qdisc scripts. It is intended to allow an easy path for distributions to make fq_codel or sfq the default qdisc. This patch also makes pfifo_fast more of a first class qdisc, since it is now possible to manually override the default and explicitly use pfifo_fast. The behavior for systems who do not use the sysctl is unchanged, they still get pfifo_fast Also removes leftover random # in sysctl net core. Signed-off-by: Stephen Hemminger Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/sched/sch_api.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++ net/sched/sch_generic.c | 11 +++++----- net/sched/sch_mq.c | 2 +- net/sched/sch_mqprio.c | 2 +- 4 files changed, 66 insertions(+), 7 deletions(-) (limited to 'net/sched') diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index 51b968d3febb..812e57900591 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -131,6 +131,11 @@ static DEFINE_RWLOCK(qdisc_mod_lock); ************************************************/ +/* Qdisc to use by default */ + +const struct Qdisc_ops *default_qdisc_ops = &pfifo_fast_ops; +EXPORT_SYMBOL(default_qdisc_ops); + /* The list of all installed queueing disciplines. */ static struct Qdisc_ops *qdisc_base; @@ -200,6 +205,58 @@ int unregister_qdisc(struct Qdisc_ops *qops) } EXPORT_SYMBOL(unregister_qdisc); +/* Get default qdisc if not otherwise specified */ +void qdisc_get_default(char *name, size_t len) +{ + read_lock(&qdisc_mod_lock); + strlcpy(name, default_qdisc_ops->id, len); + read_unlock(&qdisc_mod_lock); +} + +static struct Qdisc_ops *qdisc_lookup_default(const char *name) +{ + struct Qdisc_ops *q = NULL; + + for (q = qdisc_base; q; q = q->next) { + if (!strcmp(name, q->id)) { + if (!try_module_get(q->owner)) + q = NULL; + break; + } + } + + return q; +} + +/* Set new default qdisc to use */ +int qdisc_set_default(const char *name) +{ + const struct Qdisc_ops *ops; + + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + + write_lock(&qdisc_mod_lock); + ops = qdisc_lookup_default(name); + if (!ops) { + /* Not found, drop lock and try to load module */ + write_unlock(&qdisc_mod_lock); + request_module("sch_%s", name); + write_lock(&qdisc_mod_lock); + + ops = qdisc_lookup_default(name); + } + + if (ops) { + /* Set new default */ + module_put(default_qdisc_ops->owner); + default_qdisc_ops = ops; + } + write_unlock(&qdisc_mod_lock); + + return ops ? 0 : -ENOENT; +} + /* We know handle. Find qdisc among all qdisc's attached to device (root qdisc, all its children, children of children etc.) */ @@ -1854,6 +1911,7 @@ static int __init pktsched_init(void) return err; } + register_qdisc(&pfifo_fast_ops); register_qdisc(&pfifo_qdisc_ops); register_qdisc(&bfifo_qdisc_ops); register_qdisc(&pfifo_head_drop_qdisc_ops); diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 48be3d5c0d92..5078e0c5db8d 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -530,7 +530,6 @@ struct Qdisc_ops pfifo_fast_ops __read_mostly = { .dump = pfifo_fast_dump, .owner = THIS_MODULE, }; -EXPORT_SYMBOL(pfifo_fast_ops); static struct lock_class_key qdisc_tx_busylock; @@ -583,6 +582,9 @@ struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue, { struct Qdisc *sch; + if (!try_module_get(ops->owner)) + goto errout; + sch = qdisc_alloc(dev_queue, ops); if (IS_ERR(sch)) goto errout; @@ -686,7 +688,7 @@ static void attach_one_default_qdisc(struct net_device *dev, if (dev->tx_queue_len) { qdisc = qdisc_create_dflt(dev_queue, - &pfifo_fast_ops, TC_H_ROOT); + default_qdisc_ops, TC_H_ROOT); if (!qdisc) { netdev_info(dev, "activation failed\n"); return; @@ -739,9 +741,8 @@ void dev_activate(struct net_device *dev) int need_watchdog; /* No queueing discipline is attached to device; - create default one i.e. pfifo_fast for devices, - which need queueing and noqueue_qdisc for - virtual interfaces + * create default one for devices, which need queueing + * and noqueue_qdisc for virtual interfaces */ if (dev->qdisc == &noop_qdisc) diff --git a/net/sched/sch_mq.c b/net/sched/sch_mq.c index 5da78a19ac9a..2e56185736d6 100644 --- a/net/sched/sch_mq.c +++ b/net/sched/sch_mq.c @@ -57,7 +57,7 @@ static int mq_init(struct Qdisc *sch, struct nlattr *opt) for (ntx = 0; ntx < dev->num_tx_queues; ntx++) { dev_queue = netdev_get_tx_queue(dev, ntx); - qdisc = qdisc_create_dflt(dev_queue, &pfifo_fast_ops, + qdisc = qdisc_create_dflt(dev_queue, default_qdisc_ops, TC_H_MAKE(TC_H_MAJ(sch->handle), TC_H_MIN(ntx + 1))); if (qdisc == NULL) diff --git a/net/sched/sch_mqprio.c b/net/sched/sch_mqprio.c index accec33c454c..d44c868cb537 100644 --- a/net/sched/sch_mqprio.c +++ b/net/sched/sch_mqprio.c @@ -124,7 +124,7 @@ static int mqprio_init(struct Qdisc *sch, struct nlattr *opt) for (i = 0; i < dev->num_tx_queues; i++) { dev_queue = netdev_get_tx_queue(dev, i); - qdisc = qdisc_create_dflt(dev_queue, &pfifo_fast_ops, + qdisc = qdisc_create_dflt(dev_queue, default_qdisc_ops, TC_H_MAKE(TC_H_MAJ(sch->handle), TC_H_MIN(i + 1))); if (qdisc == NULL) { -- cgit v1.2.3 From d2a7f269f91299b8e5f6c7d2a41ba46248d73d24 Mon Sep 17 00:00:00 2001 From: stephen hemminger Date: Sat, 31 Aug 2013 10:15:50 -0700 Subject: qdisc: make args to qdisc_create_default const Fixes warnings introduced by the qdisc default patch. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- net/sched/sch_generic.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'net/sched') diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 5078e0c5db8d..6b021106542c 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -534,7 +534,7 @@ struct Qdisc_ops pfifo_fast_ops __read_mostly = { static struct lock_class_key qdisc_tx_busylock; struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue, - struct Qdisc_ops *ops) + const struct Qdisc_ops *ops) { void *p; struct Qdisc *sch; @@ -578,7 +578,8 @@ errout: } struct Qdisc *qdisc_create_dflt(struct netdev_queue *dev_queue, - struct Qdisc_ops *ops, unsigned int parentid) + const struct Qdisc_ops *ops, + unsigned int parentid) { struct Qdisc *sch; -- cgit v1.2.3 From 34aedd3f3b289edba118e66450e95790ccab5091 Mon Sep 17 00:00:00 2001 From: stephen hemminger Date: Sat, 31 Aug 2013 10:15:33 -0700 Subject: qdisc: fix build with !CONFIG_NET_SCHED Multiqueue scheduler refers to default_qdisc_ops; therefore the variable definition needs to be moved to handle case where net scheduler API is not available. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- net/sched/sch_api.c | 5 ----- net/sched/sch_generic.c | 4 ++++ 2 files changed, 4 insertions(+), 5 deletions(-) (limited to 'net/sched') diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index 812e57900591..2adda7fa2d39 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -131,11 +131,6 @@ static DEFINE_RWLOCK(qdisc_mod_lock); ************************************************/ -/* Qdisc to use by default */ - -const struct Qdisc_ops *default_qdisc_ops = &pfifo_fast_ops; -EXPORT_SYMBOL(default_qdisc_ops); - /* The list of all installed queueing disciplines. */ static struct Qdisc_ops *qdisc_base; diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 6b021106542c..a74e278654aa 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -30,6 +30,10 @@ #include #include +/* Qdisc to use by default */ +const struct Qdisc_ops *default_qdisc_ops = &pfifo_fast_ops; +EXPORT_SYMBOL(default_qdisc_ops); + /* Main transmission queue. */ /* Modifications to data participating in scheduling must be protected with -- cgit v1.2.3