linux-stable/net/sched/sch_fq.c
Eric Dumazet fefa569a9d net_sched: sch_fq: account for schedule/timers drifts
It looks like the following patch can make FQ very precise, even in VM
or stressed hosts. It matters at high pacing rates.

We take into account the difference between the time that was programmed
when last packet was sent, and current time (a drift of tens of usecs is
often observed)

Add an EWMA of the unthrottle latency to help diagnostics.

This latency is the difference between current time and oldest packet in
delayed RB-tree. This accounts for the high resolution timer latency,
but can be different under stress, as fq_check_throttled() can be
opportunistically be called from a dequeue() called after an enqueue()
for a different flow.

Tested:
// Start a 10Gbit flow
$ netperf --google-pacing-rate 1250000000 -H lpaa24 -l 10000 -- -K bbr &

Before patch :
$ sar -n DEV 10 5 | grep eth0 | grep Average
Average:         eth0  17106.04 756876.84   1102.75 1119049.02      0.00      0.00      0.52

After patch :
$ sar -n DEV 10 5 | grep eth0 | grep Average
Average:         eth0  17867.00 800245.90   1151.77 1183172.12      0.00      0.00      0.52

A new iproute2 tc can output the 'unthrottle latency' :

$ tc -s qd sh dev eth0 | grep latency
  0 gc, 0 highprio, 32490767 throttled, 2382 ns latency

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-23 07:19:06 -04:00

920 lines
22 KiB
C

/*
* net/sched/sch_fq.c Fair Queue Packet Scheduler (per flow pacing)
*
* Copyright (C) 2013-2015 Eric Dumazet <edumazet@google.com>
*
* 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 locally 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 <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/string.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/rbtree.h>
#include <linux/hash.h>
#include <linux/prefetch.h>
#include <linux/vmalloc.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/tcp.h>
/*
* 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;
unsigned long unthrottle_latency_ns;
struct fq_flow internal; /* for non classified or high prio packets */
u32 quantum;
u32 initial_quantum;
u32 flow_refill_delay;
u32 flow_max_rate; /* optional max rate per flow */
u32 flow_plimit; /* max packets per flow */
u32 orphan_mask; /* mask for orphaned skb */
u32 low_rate_threshold;
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;
f->age = jiffies;
}
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 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;
/* warning: no starvation prevention... */
if (unlikely((skb->priority & TC_PRIO_MAX) == TC_PRIO_CONTROL))
return &q->internal;
/* SYNACK messages are attached to a TCP_NEW_SYN_RECV request socket
* or a listener (SYNCOOKIE mode)
* 1) request sockets are not full blown,
* they do not contain sk_pacing_rate
* 2) They are not part of a 'flow' yet
* 3) We do not want to rate limit them (eg SYNFLOOD attack),
* especially if the listener set SO_MAX_PACING_RATE
* 4) We pretend they are orphaned
*/
if (!sk || sk_listener(sk)) {
unsigned long hash = skb_get_hash(skb) & q->orphan_mask;
/* 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 *)((hash << 1) | 1UL);
skb_orphan(skb);
}
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;
f->time_next_packet = 0ULL;
}
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 Qdisc *sch, struct fq_flow *flow)
{
struct sk_buff *skb = flow->head;
if (skb) {
flow->head = skb->next;
skb->next = NULL;
flow->qlen--;
qdisc_qstats_backlog_dec(sch, skb);
sch->q.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 sk_buff **to_free)
{
struct fq_sched_data *q = qdisc_priv(sch);
struct fq_flow *f;
if (unlikely(sch->q.qlen >= sch->limit))
return qdisc_drop(skb, sch, to_free);
f = fq_classify(skb, q);
if (unlikely(f->qlen >= q->flow_plimit && f != &q->internal)) {
q->stat_flows_plimit++;
return qdisc_drop(skb, sch, to_free);
}
f->qlen++;
if (skb_is_retransmit(skb))
q->stat_tcp_retrans++;
qdisc_qstats_backlog_inc(sch, skb);
if (fq_flow_is_detached(f)) {
fq_flow_add_tail(&q->new_flows, f);
if (time_after(jiffies, f->age + q->flow_refill_delay))
f->credit = max_t(u32, f->credit, q->quantum);
q->inactive_flows--;
}
/* Note: this overwrites f->age */
flow_queue_add(f, skb);
if (unlikely(f == &q->internal)) {
q->stat_internal_packets++;
}
sch->q.qlen++;
return NET_XMIT_SUCCESS;
}
static void fq_check_throttled(struct fq_sched_data *q, u64 now)
{
unsigned long sample;
struct rb_node *p;
if (q->time_next_delayed_flow > now)
return;
/* Update unthrottle latency EWMA.
* This is cheap and can help diagnosing timer/latency problems.
*/
sample = (unsigned long)(now - q->time_next_delayed_flow);
q->unthrottle_latency_ns -= q->unthrottle_latency_ns >> 3;
q->unthrottle_latency_ns += sample >> 3;
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_get_ns();
struct fq_flow_head *head;
struct sk_buff *skb;
struct fq_flow *f;
u32 rate, plen;
skb = fq_dequeue_head(sch, &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;
}
skb = f->head;
if (unlikely(skb && now < f->time_next_packet &&
!skb_is_tcp_pure_ack(skb))) {
head->first = f->next;
fq_flow_set_throttled(q, f);
goto begin;
}
skb = fq_dequeue_head(sch, 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);
q->inactive_flows++;
}
goto begin;
}
prefetch(&skb->end);
f->credit -= qdisc_pkt_len(skb);
if (!q->rate_enable)
goto out;
/* Do not pace locally generated ack packets */
if (skb_is_tcp_pure_ack(skb))
goto out;
rate = q->flow_max_rate;
if (skb->sk)
rate = min(skb->sk->sk_pacing_rate, rate);
if (rate <= q->low_rate_threshold) {
f->credit = 0;
plen = qdisc_pkt_len(skb);
} else {
plen = max(qdisc_pkt_len(skb), q->quantum);
if (f->credit > 0)
goto out;
}
if (rate != ~0U) {
u64 len = (u64)plen * NSEC_PER_SEC;
if (likely(rate))
do_div(len, rate);
/* Since socket rate can change later,
* clamp the delay to 1 second.
* Really, providers of too big packets should be fixed !
*/
if (unlikely(len > NSEC_PER_SEC)) {
len = NSEC_PER_SEC;
q->stat_pkts_too_long++;
}
/* Account for schedule/timers drifts.
* f->time_next_packet was set when prior packet was sent,
* and current time (@now) can be too late by tens of us.
*/
if (f->time_next_packet)
len -= min(len/2, now - f->time_next_packet);
f->time_next_packet = now + len;
}
out:
qdisc_bstats_update(sch, skb);
return skb;
}
static void fq_flow_purge(struct fq_flow *flow)
{
rtnl_kfree_skbs(flow->head, flow->tail);
flow->head = NULL;
flow->qlen = 0;
}
static void fq_reset(struct Qdisc *sch)
{
struct fq_sched_data *q = qdisc_priv(sch);
struct rb_root *root;
struct rb_node *p;
struct fq_flow *f;
unsigned int idx;
sch->q.qlen = 0;
sch->qstats.backlog = 0;
fq_flow_purge(&q->internal);
if (!q->fq_root)
return;
for (idx = 0; idx < (1U << q->fq_trees_log); idx++) {
root = &q->fq_root[idx];
while ((p = rb_first(root)) != NULL) {
f = container_of(p, struct fq_flow, fq_node);
rb_erase(p, root);
fq_flow_purge(f);
kmem_cache_free(fq_flow_cachep, f);
}
}
q->new_flows.first = NULL;
q->old_flows.first = NULL;
q->delayed = RB_ROOT;
q->flows = 0;
q->inactive_flows = 0;
q->throttled_flows = 0;
}
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 void *fq_alloc_node(size_t sz, int node)
{
void *ptr;
ptr = kmalloc_node(sz, GFP_KERNEL | __GFP_REPEAT | __GFP_NOWARN, node);
if (!ptr)
ptr = vmalloc_node(sz, node);
return ptr;
}
static void fq_free(void *addr)
{
kvfree(addr);
}
static int fq_resize(struct Qdisc *sch, u32 log)
{
struct fq_sched_data *q = qdisc_priv(sch);
struct rb_root *array;
void *old_fq_root;
u32 idx;
if (q->fq_root && log == q->fq_trees_log)
return 0;
/* If XPS was setup, we can allocate memory on right NUMA node */
array = fq_alloc_node(sizeof(struct rb_root) << log,
netdev_queue_numa_node_read(sch->dev_queue));
if (!array)
return -ENOMEM;
for (idx = 0; idx < (1U << log); idx++)
array[idx] = RB_ROOT;
sch_tree_lock(sch);
old_fq_root = q->fq_root;
if (old_fq_root)
fq_rehash(q, old_fq_root, q->fq_trees_log, array, log);
q->fq_root = array;
q->fq_trees_log = log;
sch_tree_unlock(sch);
fq_free(old_fq_root);
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 },
[TCA_FQ_FLOW_REFILL_DELAY] = { .type = NLA_U32 },
[TCA_FQ_LOW_RATE_THRESHOLD] = { .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;
unsigned drop_len = 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]) {
u32 quantum = nla_get_u32(tb[TCA_FQ_QUANTUM]);
if (quantum > 0)
q->quantum = quantum;
else
err = -EINVAL;
}
if (tb[TCA_FQ_INITIAL_QUANTUM])
q->initial_quantum = nla_get_u32(tb[TCA_FQ_INITIAL_QUANTUM]);
if (tb[TCA_FQ_FLOW_DEFAULT_RATE])
pr_warn_ratelimited("sch_fq: defrate %u ignored.\n",
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_LOW_RATE_THRESHOLD])
q->low_rate_threshold =
nla_get_u32(tb[TCA_FQ_LOW_RATE_THRESHOLD]);
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 (tb[TCA_FQ_FLOW_REFILL_DELAY]) {
u32 usecs_delay = nla_get_u32(tb[TCA_FQ_FLOW_REFILL_DELAY]) ;
q->flow_refill_delay = usecs_to_jiffies(usecs_delay);
}
if (tb[TCA_FQ_ORPHAN_MASK])
q->orphan_mask = nla_get_u32(tb[TCA_FQ_ORPHAN_MASK]);
if (!err) {
sch_tree_unlock(sch);
err = fq_resize(sch, fq_log);
sch_tree_lock(sch);
}
while (sch->q.qlen > sch->limit) {
struct sk_buff *skb = fq_dequeue(sch);
if (!skb)
break;
drop_len += qdisc_pkt_len(skb);
rtnl_kfree_skbs(skb, skb);
drop_count++;
}
qdisc_tree_reduce_backlog(sch, drop_count, drop_len);
sch_tree_unlock(sch);
return err;
}
static void fq_destroy(struct Qdisc *sch)
{
struct fq_sched_data *q = qdisc_priv(sch);
fq_reset(sch);
fq_free(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_refill_delay = msecs_to_jiffies(40);
q->flow_max_rate = ~0U;
q->time_next_delayed_flow = ~0ULL;
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);
q->orphan_mask = 1024 - 1;
q->low_rate_threshold = 550000 / 8;
qdisc_watchdog_init(&q->watchdog, sch);
if (opt)
err = fq_change(sch, opt);
else
err = fq_resize(sch, 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;
/* TCA_FQ_FLOW_DEFAULT_RATE is not used anymore */
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_MAX_RATE, q->flow_max_rate) ||
nla_put_u32(skb, TCA_FQ_FLOW_REFILL_DELAY,
jiffies_to_usecs(q->flow_refill_delay)) ||
nla_put_u32(skb, TCA_FQ_ORPHAN_MASK, q->orphan_mask) ||
nla_put_u32(skb, TCA_FQ_LOW_RATE_THRESHOLD,
q->low_rate_threshold) ||
nla_put_u32(skb, TCA_FQ_BUCKETS_LOG, q->fq_trees_log))
goto nla_put_failure;
return nla_nest_end(skb, opts);
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);
struct tc_fq_qd_stats st;
sch_tree_lock(sch);
st.gc_flows = q->stat_gc_flows;
st.highprio_packets = q->stat_internal_packets;
st.tcp_retrans = q->stat_tcp_retrans;
st.throttled = q->stat_throttled;
st.flows_plimit = q->stat_flows_plimit;
st.pkts_too_long = q->stat_pkts_too_long;
st.allocation_errors = q->stat_allocation_errors;
st.time_next_delayed_flow = q->time_next_delayed_flow - ktime_get_ns();
st.flows = q->flows;
st.inactive_flows = q->inactive_flows;
st.throttled_flows = q->throttled_flows;
st.unthrottle_latency_ns = min_t(unsigned long,
q->unthrottle_latency_ns, ~0U);
sch_tree_unlock(sch);
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");