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sch_fq.c
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* net/sched/sch_fq.c Fair Queue Packet Scheduler (per flow pacing)
*
* Copyright (C) 2013-2023 Eric Dumazet <edumazet@google.com>
*
* 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>
struct fq_skb_cb {
u64 time_to_send;
u8 band;
};
static inline struct fq_skb_cb *fq_skb_cb(struct sk_buff *skb)
{
qdisc_cb_private_validate(skb, sizeof(struct fq_skb_cb));
return (struct fq_skb_cb *)qdisc_skb_cb(skb)->data;
}
/*
* Per flow structure, dynamically allocated.
* If packets have monotically increasing time_to_send, they are placed in O(1)
* in linear list (head,tail), otherwise are placed in a rbtree (t_root).
*/
struct fq_flow {
/* First cache line : used in fq_gc(), fq_enqueue(), fq_dequeue() */
struct rb_root t_root;
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 | 1UL) when flow was emptied, for gc */
};
union {
struct rb_node fq_node; /* anchor in fq_root[] trees */
/* Following field is only used for q->internal,
* because q->internal is not hashed in fq_root[]
*/
u64 stat_fastpath_packets;
};
struct sock *sk;
u32 socket_hash; /* sk_hash */
int qlen; /* number of packets in flow queue */
/* Second cache line */
int credit;
int band;
struct fq_flow *next; /* next pointer in RR lists */
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_perband_flows {
struct fq_flow_head new_flows;
struct fq_flow_head old_flows;
int credit;
int quantum; /* based on band nr : 576KB, 192KB, 64KB */
};
#define FQ_PRIO2BAND_CRUMB_SIZE ((TC_PRIO_MAX + 1) >> 2)
struct fq_sched_data {
/* Read mostly cache line */
u32 quantum;
u32 initial_quantum;
u32 flow_refill_delay;
u32 flow_plimit; /* max packets per flow */
unsigned long flow_max_rate; /* optional max rate per flow */
u64 ce_threshold;
u64 horizon; /* horizon in ns */
u32 orphan_mask; /* mask for orphaned skb */
u32 low_rate_threshold;
struct rb_root *fq_root;
u8 rate_enable;
u8 fq_trees_log;
u8 horizon_drop;
u8 prio2band[FQ_PRIO2BAND_CRUMB_SIZE];
u32 timer_slack; /* hrtimer slack in ns */
/* Read/Write fields. */
unsigned int band_nr; /* band being serviced in fq_dequeue() */
struct fq_perband_flows band_flows[FQ_BANDS];
struct fq_flow internal; /* fastpath queue. */
struct rb_root delayed; /* for rate limited flows */
u64 time_next_delayed_flow;
unsigned long unthrottle_latency_ns;
u32 band_pkt_count[FQ_BANDS];
u32 flows;
u32 inactive_flows; /* Flows with no packet to send. */
u32 throttled_flows;
u64 stat_throttled;
struct qdisc_watchdog watchdog;
u64 stat_gc_flows;
/* Seldom used fields. */
u64 stat_band_drops[FQ_BANDS];
u64 stat_ce_mark;
u64 stat_horizon_drops;
u64 stat_horizon_caps;
u64 stat_flows_plimit;
u64 stat_pkts_too_long;
u64 stat_allocation_errors;
};
/* return the i-th 2-bit value ("crumb") */
static u8 fq_prio2band(const u8 *prio2band, unsigned int prio)
{
return (READ_ONCE(prio2band[prio / 4]) >> (2 * (prio & 0x3))) & 0x3;
}
/*
* f->tail and f->age share the same location.
* We can use the low order bit to differentiate if this location points
* to a sk_buff or contains a jiffies value, if we force this value to be odd.
* This assumes f->tail low order bit must be 0 since alignof(struct sk_buff) >= 2
*/
static void fq_flow_set_detached(struct fq_flow *f)
{
f->age = jiffies | 1UL;
}
static bool fq_flow_is_detached(const struct fq_flow *f)
{
return !!(f->age & 1UL);
}
/* special value to mark a throttled flow (not on old/new list) */
static struct fq_flow throttled;
static bool fq_flow_is_throttled(const struct fq_flow *f)
{
return f->next == &throttled;
}
enum new_flow {
NEW_FLOW,
OLD_FLOW
};
static void fq_flow_add_tail(struct fq_sched_data *q, struct fq_flow *flow,
enum new_flow list_sel)
{
struct fq_perband_flows *pband = &q->band_flows[flow->band];
struct fq_flow_head *head = (list_sel == NEW_FLOW) ?
&pband->new_flows :
&pband->old_flows;
if (head->first)
head->last->next = flow;
else
head->first = flow;
head->last = flow;
flow->next = NULL;
}
static void fq_flow_unset_throttled(struct fq_sched_data *q, struct fq_flow *f)
{
rb_erase(&f->rate_node, &q->delayed);
q->throttled_flows--;
fq_flow_add_tail(q, f, OLD_FLOW);
}
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 = rb_entry(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;
/* 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 rb_node **p, *parent;
void *tofree[FQ_GC_MAX];
struct fq_flow *f;
int i, fcnt = 0;
p = &root->rb_node;
parent = NULL;
while (*p) {
parent = *p;
f = rb_entry(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;
}
if (!fcnt)
return;
for (i = fcnt; i > 0; ) {
f = tofree[--i];
rb_erase(&f->fq_node, root);
}
q->flows -= fcnt;
q->inactive_flows -= fcnt;
q->stat_gc_flows += fcnt;
kmem_cache_free_bulk(fq_flow_cachep, fcnt, tofree);
}
/* Fast path can be used if :
* 1) Packet tstamp is in the past.
* 2) FQ qlen == 0 OR
* (no flow is currently eligible for transmit,
* AND fast path queue has less than 8 packets)
* 3) No SO_MAX_PACING_RATE on the socket (if any).
* 4) No @maxrate attribute on this qdisc,
*
* FQ can not use generic TCQ_F_CAN_BYPASS infrastructure.
*/
static bool fq_fastpath_check(const struct Qdisc *sch, struct sk_buff *skb,
u64 now)
{
const struct fq_sched_data *q = qdisc_priv(sch);
const struct sock *sk;
if (fq_skb_cb(skb)->time_to_send > now)
return false;
if (sch->q.qlen != 0) {
/* Even if some packets are stored in this qdisc,
* we can still enable fast path if all of them are
* scheduled in the future (ie no flows are eligible)
* or in the fast path queue.
*/
if (q->flows != q->inactive_flows + q->throttled_flows)
return false;
/* Do not allow fast path queue to explode, we want Fair Queue mode
* under pressure.
*/
if (q->internal.qlen >= 8)
return false;
/* Ordering invariants fall apart if some delayed flows
* are ready but we haven't serviced them, yet.
*/
if (q->time_next_delayed_flow <= now)
return false;
}
sk = skb->sk;
if (sk && sk_fullsock(sk) && !sk_is_tcp(sk) &&
sk->sk_max_pacing_rate != ~0UL)
return false;
if (q->flow_max_rate != ~0UL)
return false;
return true;
}
static struct fq_flow *fq_classify(struct Qdisc *sch, struct sk_buff *skb,
u64 now)
{
struct fq_sched_data *q = qdisc_priv(sch);
struct rb_node **p, *parent;
struct sock *sk = skb->sk;
struct rb_root *root;
struct fq_flow *f;
/* 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);
} else if (sk->sk_state == TCP_CLOSE) {
unsigned long hash = skb_get_hash(skb) & q->orphan_mask;
/*
* Sockets in TCP_CLOSE are non connected.
* Typical use case is UDP sockets, they can send packets
* with sendto() to many different destinations.
* We probably could use a generic bit advertising
* non connected sockets, instead of sk_state == TCP_CLOSE,
* if we care enough.
*/
sk = (struct sock *)((hash << 1) | 1UL);
}
if (fq_fastpath_check(sch, skb, now)) {
q->internal.stat_fastpath_packets++;
if (skb->sk == sk && q->rate_enable &&
READ_ONCE(sk->sk_pacing_status) != SK_PACING_FQ)
smp_store_release(&sk->sk_pacing_status,
SK_PACING_FQ);
return &q->internal;
}
root = &q->fq_root[hash_ptr(sk, q->fq_trees_log)];
fq_gc(q, root, sk);
p = &root->rb_node;
parent = NULL;
while (*p) {
parent = *p;
f = rb_entry(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 == sk &&
f->socket_hash != sk->sk_hash)) {
f->credit = q->initial_quantum;
f->socket_hash = sk->sk_hash;
if (q->rate_enable)
smp_store_release(&sk->sk_pacing_status,
SK_PACING_FQ);
if (fq_flow_is_throttled(f))
fq_flow_unset_throttled(q, f);
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;
}
/* f->t_root is already zeroed after kmem_cache_zalloc() */
fq_flow_set_detached(f);
f->sk = sk;
if (skb->sk == sk) {
f->socket_hash = sk->sk_hash;
if (q->rate_enable)
smp_store_release(&sk->sk_pacing_status,
SK_PACING_FQ);
}
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;
}
static struct sk_buff *fq_peek(struct fq_flow *flow)
{
struct sk_buff *skb = skb_rb_first(&flow->t_root);
struct sk_buff *head = flow->head;
if (!skb)
return head;
if (!head)
return skb;
if (fq_skb_cb(skb)->time_to_send < fq_skb_cb(head)->time_to_send)
return skb;
return head;
}
static void fq_erase_head(struct Qdisc *sch, struct fq_flow *flow,
struct sk_buff *skb)
{
if (skb == flow->head) {
flow->head = skb->next;
} else {
rb_erase(&skb->rbnode, &flow->t_root);
skb->dev = qdisc_dev(sch);
}
}
/* Remove one skb from flow queue.
* This skb must be the return value of prior fq_peek().
*/
static void fq_dequeue_skb(struct Qdisc *sch, struct fq_flow *flow,
struct sk_buff *skb)
{
fq_erase_head(sch, flow, skb);
skb_mark_not_on_list(skb);
qdisc_qstats_backlog_dec(sch, skb);
sch->q.qlen--;
}
static void flow_queue_add(struct fq_flow *flow, struct sk_buff *skb)
{
struct rb_node **p, *parent;
struct sk_buff *head, *aux;
head = flow->head;
if (!head ||
fq_skb_cb(skb)->time_to_send >= fq_skb_cb(flow->tail)->time_to_send) {
if (!head)
flow->head = skb;
else
flow->tail->next = skb;
flow->tail = skb;
skb->next = NULL;
return;
}
p = &flow->t_root.rb_node;
parent = NULL;
while (*p) {
parent = *p;
aux = rb_to_skb(parent);
if (fq_skb_cb(skb)->time_to_send >= fq_skb_cb(aux)->time_to_send)
p = &parent->rb_right;
else
p = &parent->rb_left;
}
rb_link_node(&skb->rbnode, parent, p);
rb_insert_color(&skb->rbnode, &flow->t_root);
}
static bool fq_packet_beyond_horizon(const struct sk_buff *skb,
const struct fq_sched_data *q, u64 now)
{
return unlikely((s64)skb->tstamp > (s64)(now + q->horizon));
}
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;
u64 now;
u8 band;
band = fq_prio2band(q->prio2band, skb->priority & TC_PRIO_MAX);
if (unlikely(q->band_pkt_count[band] >= sch->limit)) {
q->stat_band_drops[band]++;
return qdisc_drop(skb, sch, to_free);
}
now = ktime_get_ns();
if (!skb->tstamp) {
fq_skb_cb(skb)->time_to_send = now;
} else {
/* Check if packet timestamp is too far in the future. */
if (fq_packet_beyond_horizon(skb, q, now)) {
if (q->horizon_drop) {
q->stat_horizon_drops++;
return qdisc_drop(skb, sch, to_free);
}
q->stat_horizon_caps++;
skb->tstamp = now + q->horizon;
}
fq_skb_cb(skb)->time_to_send = skb->tstamp;
}
f = fq_classify(sch, skb, now);
if (f != &q->internal) {
if (unlikely(f->qlen >= q->flow_plimit)) {
q->stat_flows_plimit++;
return qdisc_drop(skb, sch, to_free);
}
if (fq_flow_is_detached(f)) {
fq_flow_add_tail(q, f, NEW_FLOW);
if (time_after(jiffies, f->age + q->flow_refill_delay))
f->credit = max_t(u32, f->credit, q->quantum);
}
f->band = band;
q->band_pkt_count[band]++;
fq_skb_cb(skb)->band = band;
if (f->qlen == 0)
q->inactive_flows--;
}
f->qlen++;
/* Note: this overwrites f->age */
flow_queue_add(f, skb);
qdisc_qstats_backlog_inc(sch, skb);
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 = rb_entry(p, struct fq_flow, rate_node);
if (f->time_next_packet > now) {
q->time_next_delayed_flow = f->time_next_packet;
break;
}
fq_flow_unset_throttled(q, f);
}
}
static struct fq_flow_head *fq_pband_head_select(struct fq_perband_flows *pband)
{
if (pband->credit <= 0)
return NULL;
if (pband->new_flows.first)
return &pband->new_flows;
return pband->old_flows.first ? &pband->old_flows : NULL;
}
static struct sk_buff *fq_dequeue(struct Qdisc *sch)
{
struct fq_sched_data *q = qdisc_priv(sch);
struct fq_perband_flows *pband;
struct fq_flow_head *head;
struct sk_buff *skb;
struct fq_flow *f;
unsigned long rate;
int retry;
u32 plen;
u64 now;
if (!sch->q.qlen)
return NULL;
skb = fq_peek(&q->internal);
if (unlikely(skb)) {
q->internal.qlen--;
fq_dequeue_skb(sch, &q->internal, skb);
goto out;
}
now = ktime_get_ns();
fq_check_throttled(q, now);
retry = 0;
pband = &q->band_flows[q->band_nr];
begin:
head = fq_pband_head_select(pband);
if (!head) {
while (++retry <= FQ_BANDS) {
if (++q->band_nr == FQ_BANDS)
q->band_nr = 0;
pband = &q->band_flows[q->band_nr];
pband->credit = min(pband->credit + pband->quantum,
pband->quantum);
if (pband->credit > 0)
goto begin;
retry = 0;
}
if (q->time_next_delayed_flow != ~0ULL)
qdisc_watchdog_schedule_range_ns(&q->watchdog,
q->time_next_delayed_flow,
q->timer_slack);
return NULL;
}
f = head->first;
retry = 0;
if (f->credit <= 0) {
f->credit += q->quantum;
head->first = f->next;
fq_flow_add_tail(q, f, OLD_FLOW);
goto begin;
}
skb = fq_peek(f);
if (skb) {
u64 time_next_packet = max_t(u64, fq_skb_cb(skb)->time_to_send,
f->time_next_packet);
if (now < time_next_packet) {
head->first = f->next;
f->time_next_packet = time_next_packet;
fq_flow_set_throttled(q, f);
goto begin;
}
prefetch(&skb->end);
if ((s64)(now - time_next_packet - q->ce_threshold) > 0) {
INET_ECN_set_ce(skb);
q->stat_ce_mark++;
}
if (--f->qlen == 0)
q->inactive_flows++;
q->band_pkt_count[fq_skb_cb(skb)->band]--;
fq_dequeue_skb(sch, f, skb);
} else {
head->first = f->next;
/* force a pass through old_flows to prevent starvation */
if (head == &pband->new_flows) {
fq_flow_add_tail(q, f, OLD_FLOW);
} else {
fq_flow_set_detached(f);
}
goto begin;
}
plen = qdisc_pkt_len(skb);
f->credit -= plen;
pband->credit -= plen;
if (!q->rate_enable)
goto out;
rate = q->flow_max_rate;
/* If EDT time was provided for this skb, we need to
* update f->time_next_packet only if this qdisc enforces
* a flow max rate.
*/
if (!skb->tstamp) {
if (skb->sk)
rate = min(READ_ONCE(skb->sk->sk_pacing_rate), rate);
if (rate <= q->low_rate_threshold) {
f->credit = 0;
} else {
plen = max(plen, q->quantum);
if (f->credit > 0)
goto out;
}
}
if (rate != ~0UL) {
u64 len = (u64)plen * NSEC_PER_SEC;
if (likely(rate))
len = div64_ul(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)
{
struct rb_node *p = rb_first(&flow->t_root);
while (p) {
struct sk_buff *skb = rb_to_skb(p);
p = rb_next(p);
rb_erase(&skb->rbnode, &flow->t_root);
rtnl_kfree_skbs(skb, skb);
}
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 = rb_entry(p, struct fq_flow, fq_node);
rb_erase(p, root);
fq_flow_purge(f);
kmem_cache_free(fq_flow_cachep, f);
}
}
for (idx = 0; idx < FQ_BANDS; idx++) {
q->band_flows[idx].new_flows.first = NULL;
q->band_flows[idx].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 = rb_entry(op, struct fq_flow, fq_node);
if (fq_gc_candidate(of)) {
fcnt++;
kmem_cache_free(fq_flow_cachep, of);
continue;
}
nroot = &new_array[hash_ptr(of->sk, new_log)];
np = &nroot->rb_node;
parent = NULL;
while (*np) {
parent = *np;
nf = rb_entry(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_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 = kvmalloc_node(sizeof(struct rb_root) << log, GFP_KERNEL | __GFP_RETRY_MAYFAIL,
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;
WRITE_ONCE(q->fq_trees_log, log);
sch_tree_unlock(sch);
fq_free(old_fq_root);
return 0;
}
static const struct netlink_range_validation iq_range = {
.max = INT_MAX,
};
static const struct nla_policy fq_policy[TCA_FQ_MAX + 1] = {
[TCA_FQ_UNSPEC] = { .strict_start_type = TCA_FQ_TIMER_SLACK },
[TCA_FQ_PLIMIT] = { .type = NLA_U32 },
[TCA_FQ_FLOW_PLIMIT] = { .type = NLA_U32 },
[TCA_FQ_QUANTUM] = { .type = NLA_U32 },
[TCA_FQ_INITIAL_QUANTUM] = NLA_POLICY_FULL_RANGE(NLA_U32, &iq_range),
[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_ORPHAN_MASK] = { .type = NLA_U32 },
[TCA_FQ_LOW_RATE_THRESHOLD] = { .type = NLA_U32 },
[TCA_FQ_CE_THRESHOLD] = { .type = NLA_U32 },
[TCA_FQ_TIMER_SLACK] = { .type = NLA_U32 },
[TCA_FQ_HORIZON] = { .type = NLA_U32 },
[TCA_FQ_HORIZON_DROP] = { .type = NLA_U8 },
[TCA_FQ_PRIOMAP] = NLA_POLICY_EXACT_LEN(sizeof(struct tc_prio_qopt)),
[TCA_FQ_WEIGHTS] = NLA_POLICY_EXACT_LEN(FQ_BANDS * sizeof(s32)),
};
/* compress a u8 array with all elems <= 3 to an array of 2-bit fields */
static void fq_prio2band_compress_crumb(const u8 *in, u8 *out)
{
const int num_elems = TC_PRIO_MAX + 1;
u8 tmp[FQ_PRIO2BAND_CRUMB_SIZE];
int i;
memset(tmp, 0, sizeof(tmp));
for (i = 0; i < num_elems; i++)
tmp[i / 4] |= in[i] << (2 * (i & 0x3));
for (i = 0; i < FQ_PRIO2BAND_CRUMB_SIZE; i++)
WRITE_ONCE(out[i], tmp[i]);
}
static void fq_prio2band_decompress_crumb(const u8 *in, u8 *out)
{
const int num_elems = TC_PRIO_MAX + 1;
int i;
for (i = 0; i < num_elems; i++)
out[i] = fq_prio2band(in, i);
}
static int fq_load_weights(struct fq_sched_data *q,
const struct nlattr *attr,
struct netlink_ext_ack *extack)
{
s32 *weights = nla_data(attr);
int i;
for (i = 0; i < FQ_BANDS; i++) {
if (weights[i] < FQ_MIN_WEIGHT) {
NL_SET_ERR_MSG_FMT_MOD(extack, "Weight %d less that minimum allowed %d",
weights[i], FQ_MIN_WEIGHT);
return -EINVAL;
}
}
for (i = 0; i < FQ_BANDS; i++)
WRITE_ONCE(q->band_flows[i].quantum, weights[i]);
return 0;
}
static int fq_load_priomap(struct fq_sched_data *q,
const struct nlattr *attr,
struct netlink_ext_ack *extack)
{
const struct tc_prio_qopt *map = nla_data(attr);
int i;
if (map->bands != FQ_BANDS) {
NL_SET_ERR_MSG_MOD(extack, "FQ only supports 3 bands");
return -EINVAL;
}
for (i = 0; i < TC_PRIO_MAX + 1; i++) {
if (map->priomap[i] >= FQ_BANDS) {
NL_SET_ERR_MSG_FMT_MOD(extack, "FQ priomap field %d maps to a too high band %d",
i, map->priomap[i]);
return -EINVAL;
}
}
fq_prio2band_compress_crumb(map->priomap, q->prio2band);
return 0;
}