mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-21 16:29:59 +00:00
![Felix Fietkau](/assets/img/avatar_default.png)
A sorted flow list is only needed to drop packets in the biggest flow when hitting the overmemory condition. By scanning flows only when needed, we can avoid paying the cost of maintaining the list under normal conditions In order to avoid scanning lots of empty flows and touching too many cold cache lines, a bitmap of flows with backlog is maintained Signed-off-by: Felix Fietkau <nbd@nbd.name> Link: https://lore.kernel.org/r/20201218184718.93650-3-nbd@nbd.name Signed-off-by: Johannes Berg <johannes.berg@intel.com>
390 lines
7.9 KiB
C
390 lines
7.9 KiB
C
/* 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;
|
|
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;
|
|
flow->backlog += skb->len;
|
|
tin->backlog_bytes += skb->len;
|
|
tin->backlog_packets++;
|
|
fq->memory_usage += skb->truesize;
|
|
fq->backlog++;
|
|
|
|
if (list_empty(&flow->flowchain)) {
|
|
flow->deficit = fq->quantum;
|
|
list_add_tail(&flow->flowchain,
|
|
&tin->new_flows);
|
|
}
|
|
|
|
__skb_queue_tail(&flow->queue, skb);
|
|
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 = kcalloc(BITS_TO_LONGS(fq->flows_cnt), sizeof(long),
|
|
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;
|
|
|
|
kfree(fq->flows_bitmap);
|
|
fq->flows_bitmap = NULL;
|
|
}
|
|
|
|
#endif
|