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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (c) 2016 Qualcomm Atheros, Inc
*
* Based on net/sched/sch_fq_codel.c
*/
#ifndef __NET_SCHED_FQ_IMPL_H
#define __NET_SCHED_FQ_IMPL_H
#include <net/fq.h>
/* functions that are embedded into includer */
static void
__fq_adjust_removal(struct fq *fq, struct fq_flow *flow, unsigned int packets,
unsigned int bytes, unsigned int truesize)
{
struct fq_tin *tin = flow->tin;
int idx;
tin->backlog_bytes -= bytes;
tin->backlog_packets -= packets;
flow->backlog -= bytes;
fq->backlog -= packets;
fq->memory_usage -= truesize;
if (flow->backlog)
return;
if (flow == &tin->default_flow) {
list_del_init(&tin->tin_list);
return;
}
idx = flow - fq->flows;
__clear_bit(idx, fq->flows_bitmap);
}
static void fq_adjust_removal(struct fq *fq,
struct fq_flow *flow,
struct sk_buff *skb)
{
__fq_adjust_removal(fq, flow, 1, skb->len, skb->truesize);
}
static struct sk_buff *fq_flow_dequeue(struct fq *fq,
struct fq_flow *flow)
{
struct sk_buff *skb;
lockdep_assert_held(&fq->lock);
skb = __skb_dequeue(&flow->queue);
if (!skb)
return NULL;
fq_adjust_removal(fq, flow, skb);
return skb;
}
static int fq_flow_drop(struct fq *fq, struct fq_flow *flow,
fq_skb_free_t free_func)
{
unsigned int packets = 0, bytes = 0, truesize = 0;
struct fq_tin *tin = flow->tin;
struct sk_buff *skb;
int pending;
lockdep_assert_held(&fq->lock);
pending = min_t(int, 32, skb_queue_len(&flow->queue) / 2);
do {
skb = __skb_dequeue(&flow->queue);
if (!skb)
break;
packets++;
bytes += skb->len;
truesize += skb->truesize;
free_func(fq, tin, flow, skb);
} while (packets < pending);
__fq_adjust_removal(fq, flow, packets, bytes, truesize);
return packets;
}
static struct sk_buff *fq_tin_dequeue(struct fq *fq,
struct fq_tin *tin,
fq_tin_dequeue_t dequeue_func)
{
struct fq_flow *flow;
struct list_head *head;
struct sk_buff *skb;
lockdep_assert_held(&fq->lock);
begin:
head = &tin->new_flows;
if (list_empty(head)) {
head = &tin->old_flows;
if (list_empty(head))
return NULL;
}
flow = list_first_entry(head, struct fq_flow, flowchain);
if (flow->deficit <= 0) {
flow->deficit += fq->quantum;
list_move_tail(&flow->flowchain,
&tin->old_flows);
goto begin;
}
skb = dequeue_func(fq, tin, flow);
if (!skb) {
/* force a pass through old_flows to prevent starvation */
if ((head == &tin->new_flows) &&
!list_empty(&tin->old_flows)) {
list_move_tail(&flow->flowchain, &tin->old_flows);
} else {
list_del_init(&flow->flowchain);
flow->tin = NULL;
}
goto begin;
}
flow->deficit -= skb->len;
tin->tx_bytes += skb->len;
tin->tx_packets++;
return skb;
}
static u32 fq_flow_idx(struct fq *fq, struct sk_buff *skb)
{
u32 hash = skb_get_hash(skb);
return reciprocal_scale(hash, fq->flows_cnt);
}
static struct fq_flow *fq_flow_classify(struct fq *fq,
struct fq_tin *tin, u32 idx,
struct sk_buff *skb)
{
struct fq_flow *flow;
lockdep_assert_held(&fq->lock);
flow = &fq->flows[idx];
if (flow->tin && flow->tin != tin) {
flow = &tin->default_flow;
tin->collisions++;
fq->collisions++;
}
if (!flow->tin)
tin->flows++;
return flow;
}
static struct fq_flow *fq_find_fattest_flow(struct fq *fq)
{
struct fq_tin *tin;
struct fq_flow *flow = NULL;
u32 len = 0;
int i;
for_each_set_bit(i, fq->flows_bitmap, fq->flows_cnt) {
struct fq_flow *cur = &fq->flows[i];
unsigned int cur_len;
cur_len = cur->backlog;
if (cur_len <= len)
continue;
flow = cur;
len = cur_len;
}
list_for_each_entry(tin, &fq->tin_backlog, tin_list) {
unsigned int cur_len = tin->default_flow.backlog;
if (cur_len <= len)
continue;
flow = &tin->default_flow;
len = cur_len;
}
return flow;
}
static void fq_tin_enqueue(struct fq *fq,
struct fq_tin *tin, u32 idx,
struct sk_buff *skb,
fq_skb_free_t free_func)
{
struct fq_flow *flow;
struct sk_buff *next;
bool oom;
lockdep_assert_held(&fq->lock);
flow = fq_flow_classify(fq, tin, idx, skb);
if (!flow->backlog) {
if (flow != &tin->default_flow)
__set_bit(idx, fq->flows_bitmap);
else if (list_empty(&tin->tin_list))
list_add(&tin->tin_list, &fq->tin_backlog);
}
flow->tin = tin;
skb_list_walk_safe(skb, skb, next) {
skb_mark_not_on_list(skb);
flow->backlog += skb->len;
tin->backlog_bytes += skb->len;
tin->backlog_packets++;
fq->memory_usage += skb->truesize;
fq->backlog++;
__skb_queue_tail(&flow->queue, skb);
}
if (list_empty(&flow->flowchain)) {
flow->deficit = fq->quantum;
list_add_tail(&flow->flowchain,
&tin->new_flows);
}
oom = (fq->memory_usage > fq->memory_limit);
while (fq->backlog > fq->limit || oom) {
flow = fq_find_fattest_flow(fq);
if (!flow)
return;
if (!fq_flow_drop(fq, flow, free_func))
return;
flow->tin->overlimit++;
fq->overlimit++;
if (oom) {
fq->overmemory++;
oom = (fq->memory_usage > fq->memory_limit);
}
}
}
static void fq_flow_filter(struct fq *fq,
struct fq_flow *flow,
fq_skb_filter_t filter_func,
void *filter_data,
fq_skb_free_t free_func)
{
struct fq_tin *tin = flow->tin;
struct sk_buff *skb, *tmp;
lockdep_assert_held(&fq->lock);
skb_queue_walk_safe(&flow->queue, skb, tmp) {
if (!filter_func(fq, tin, flow, skb, filter_data))
continue;
__skb_unlink(skb, &flow->queue);
fq_adjust_removal(fq, flow, skb);
free_func(fq, tin, flow, skb);
}
}
static void fq_tin_filter(struct fq *fq,
struct fq_tin *tin,
fq_skb_filter_t filter_func,
void *filter_data,
fq_skb_free_t free_func)
{
struct fq_flow *flow;
lockdep_assert_held(&fq->lock);
list_for_each_entry(flow, &tin->new_flows, flowchain)
fq_flow_filter(fq, flow, filter_func, filter_data, free_func);
list_for_each_entry(flow, &tin->old_flows, flowchain)
fq_flow_filter(fq, flow, filter_func, filter_data, free_func);
}
static void fq_flow_reset(struct fq *fq,
struct fq_flow *flow,
fq_skb_free_t free_func)
{
struct fq_tin *tin = flow->tin;
struct sk_buff *skb;
while ((skb = fq_flow_dequeue(fq, flow)))
free_func(fq, tin, flow, skb);
if (!list_empty(&flow->flowchain)) {
list_del_init(&flow->flowchain);
if (list_empty(&tin->new_flows) &&
list_empty(&tin->old_flows))
list_del_init(&tin->tin_list);
}
flow->tin = NULL;
WARN_ON_ONCE(flow->backlog);
}
static void fq_tin_reset(struct fq *fq,
struct fq_tin *tin,
fq_skb_free_t free_func)
{
struct list_head *head;
struct fq_flow *flow;
for (;;) {
head = &tin->new_flows;
if (list_empty(head)) {
head = &tin->old_flows;
if (list_empty(head))
break;
}
flow = list_first_entry(head, struct fq_flow, flowchain);
fq_flow_reset(fq, flow, free_func);
}
WARN_ON_ONCE(!list_empty(&tin->tin_list));
WARN_ON_ONCE(tin->backlog_bytes);
WARN_ON_ONCE(tin->backlog_packets);
}
static void fq_flow_init(struct fq_flow *flow)
{
INIT_LIST_HEAD(&flow->flowchain);
__skb_queue_head_init(&flow->queue);
}
static void fq_tin_init(struct fq_tin *tin)
{
INIT_LIST_HEAD(&tin->new_flows);
INIT_LIST_HEAD(&tin->old_flows);
INIT_LIST_HEAD(&tin->tin_list);
fq_flow_init(&tin->default_flow);
}
static int fq_init(struct fq *fq, int flows_cnt)
{
int i;
memset(fq, 0, sizeof(fq[0]));
spin_lock_init(&fq->lock);
INIT_LIST_HEAD(&fq->tin_backlog);
fq->flows_cnt = max_t(u32, flows_cnt, 1);
fq->quantum = 300;
fq->limit = 8192;
fq->memory_limit = 16 << 20; /* 16 MBytes */
fq->flows = kvcalloc(fq->flows_cnt, sizeof(fq->flows[0]), GFP_KERNEL);
if (!fq->flows)
return -ENOMEM;
fq->flows_bitmap = bitmap_zalloc(fq->flows_cnt, GFP_KERNEL);
if (!fq->flows_bitmap) {
kvfree(fq->flows);
fq->flows = NULL;
return -ENOMEM;
}
for (i = 0; i < fq->flows_cnt; i++)
fq_flow_init(&fq->flows[i]);
return 0;
}
static void fq_reset(struct fq *fq,
fq_skb_free_t free_func)
{
int i;
for (i = 0; i < fq->flows_cnt; i++)
fq_flow_reset(fq, &fq->flows[i], free_func);
kvfree(fq->flows);
fq->flows = NULL;
bitmap_free(fq->flows_bitmap);
fq->flows_bitmap = NULL;
}
#endif
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