linux/net/core/net-procfs.c
Eric Dumazet a7ae7b0b2e net: make softnet_data.dropped an atomic_t
If under extreme cpu backlog pressure enqueue_to_backlog() has
to drop a packet, it could do this without dirtying a cache line
and potentially slowing down the target cpu.

Move sd->dropped into a separate cache line, and make it atomic.

In non pressure mode, this field is not touched, no need to consume
valuable space in a hot cache line.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2024-04-01 11:28:32 +01:00

384 lines
8.8 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/netdevice.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <net/wext.h>
#include <net/hotdata.h>
#include "dev.h"
static void *dev_seq_from_index(struct seq_file *seq, loff_t *pos)
{
unsigned long ifindex = *pos;
struct net_device *dev;
for_each_netdev_dump(seq_file_net(seq), dev, ifindex) {
*pos = dev->ifindex;
return dev;
}
return NULL;
}
static void *dev_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(RCU)
{
rcu_read_lock();
if (!*pos)
return SEQ_START_TOKEN;
return dev_seq_from_index(seq, pos);
}
static void *dev_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
++*pos;
return dev_seq_from_index(seq, pos);
}
static void dev_seq_stop(struct seq_file *seq, void *v)
__releases(RCU)
{
rcu_read_unlock();
}
static void dev_seq_printf_stats(struct seq_file *seq, struct net_device *dev)
{
struct rtnl_link_stats64 temp;
const struct rtnl_link_stats64 *stats = dev_get_stats(dev, &temp);
seq_printf(seq, "%6s: %7llu %7llu %4llu %4llu %4llu %5llu %10llu %9llu "
"%8llu %7llu %4llu %4llu %4llu %5llu %7llu %10llu\n",
dev->name, stats->rx_bytes, stats->rx_packets,
stats->rx_errors,
stats->rx_dropped + stats->rx_missed_errors,
stats->rx_fifo_errors,
stats->rx_length_errors + stats->rx_over_errors +
stats->rx_crc_errors + stats->rx_frame_errors,
stats->rx_compressed, stats->multicast,
stats->tx_bytes, stats->tx_packets,
stats->tx_errors, stats->tx_dropped,
stats->tx_fifo_errors, stats->collisions,
stats->tx_carrier_errors +
stats->tx_aborted_errors +
stats->tx_window_errors +
stats->tx_heartbeat_errors,
stats->tx_compressed);
}
/*
* Called from the PROCfs module. This now uses the new arbitrary sized
* /proc/net interface to create /proc/net/dev
*/
static int dev_seq_show(struct seq_file *seq, void *v)
{
if (v == SEQ_START_TOKEN)
seq_puts(seq, "Inter-| Receive "
" | Transmit\n"
" face |bytes packets errs drop fifo frame "
"compressed multicast|bytes packets errs "
"drop fifo colls carrier compressed\n");
else
dev_seq_printf_stats(seq, v);
return 0;
}
static u32 softnet_input_pkt_queue_len(struct softnet_data *sd)
{
return skb_queue_len_lockless(&sd->input_pkt_queue);
}
static u32 softnet_process_queue_len(struct softnet_data *sd)
{
return skb_queue_len_lockless(&sd->process_queue);
}
static struct softnet_data *softnet_get_online(loff_t *pos)
{
struct softnet_data *sd = NULL;
while (*pos < nr_cpu_ids)
if (cpu_online(*pos)) {
sd = &per_cpu(softnet_data, *pos);
break;
} else
++*pos;
return sd;
}
static void *softnet_seq_start(struct seq_file *seq, loff_t *pos)
{
return softnet_get_online(pos);
}
static void *softnet_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
++*pos;
return softnet_get_online(pos);
}
static void softnet_seq_stop(struct seq_file *seq, void *v)
{
}
static int softnet_seq_show(struct seq_file *seq, void *v)
{
struct softnet_data *sd = v;
u32 input_qlen = softnet_input_pkt_queue_len(sd);
u32 process_qlen = softnet_process_queue_len(sd);
unsigned int flow_limit_count = 0;
#ifdef CONFIG_NET_FLOW_LIMIT
struct sd_flow_limit *fl;
rcu_read_lock();
fl = rcu_dereference(sd->flow_limit);
if (fl)
flow_limit_count = fl->count;
rcu_read_unlock();
#endif
/* the index is the CPU id owing this sd. Since offline CPUs are not
* displayed, it would be othrwise not trivial for the user-space
* mapping the data a specific CPU
*/
seq_printf(seq,
"%08x %08x %08x %08x %08x %08x %08x %08x %08x %08x %08x %08x %08x "
"%08x %08x\n",
sd->processed, atomic_read(&sd->dropped),
sd->time_squeeze, 0,
0, 0, 0, 0, /* was fastroute */
0, /* was cpu_collision */
sd->received_rps, flow_limit_count,
input_qlen + process_qlen, (int)seq->index,
input_qlen, process_qlen);
return 0;
}
static const struct seq_operations dev_seq_ops = {
.start = dev_seq_start,
.next = dev_seq_next,
.stop = dev_seq_stop,
.show = dev_seq_show,
};
static const struct seq_operations softnet_seq_ops = {
.start = softnet_seq_start,
.next = softnet_seq_next,
.stop = softnet_seq_stop,
.show = softnet_seq_show,
};
static void *ptype_get_idx(struct seq_file *seq, loff_t pos)
{
struct list_head *ptype_list = NULL;
struct packet_type *pt = NULL;
struct net_device *dev;
loff_t i = 0;
int t;
for_each_netdev_rcu(seq_file_net(seq), dev) {
ptype_list = &dev->ptype_all;
list_for_each_entry_rcu(pt, ptype_list, list) {
if (i == pos)
return pt;
++i;
}
}
list_for_each_entry_rcu(pt, &net_hotdata.ptype_all, list) {
if (i == pos)
return pt;
++i;
}
for (t = 0; t < PTYPE_HASH_SIZE; t++) {
list_for_each_entry_rcu(pt, &ptype_base[t], list) {
if (i == pos)
return pt;
++i;
}
}
return NULL;
}
static void *ptype_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(RCU)
{
rcu_read_lock();
return *pos ? ptype_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
}
static void *ptype_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct net_device *dev;
struct packet_type *pt;
struct list_head *nxt;
int hash;
++*pos;
if (v == SEQ_START_TOKEN)
return ptype_get_idx(seq, 0);
pt = v;
nxt = pt->list.next;
if (pt->dev) {
if (nxt != &pt->dev->ptype_all)
goto found;
dev = pt->dev;
for_each_netdev_continue_rcu(seq_file_net(seq), dev) {
if (!list_empty(&dev->ptype_all)) {
nxt = dev->ptype_all.next;
goto found;
}
}
nxt = net_hotdata.ptype_all.next;
goto ptype_all;
}
if (pt->type == htons(ETH_P_ALL)) {
ptype_all:
if (nxt != &net_hotdata.ptype_all)
goto found;
hash = 0;
nxt = ptype_base[0].next;
} else
hash = ntohs(pt->type) & PTYPE_HASH_MASK;
while (nxt == &ptype_base[hash]) {
if (++hash >= PTYPE_HASH_SIZE)
return NULL;
nxt = ptype_base[hash].next;
}
found:
return list_entry(nxt, struct packet_type, list);
}
static void ptype_seq_stop(struct seq_file *seq, void *v)
__releases(RCU)
{
rcu_read_unlock();
}
static int ptype_seq_show(struct seq_file *seq, void *v)
{
struct packet_type *pt = v;
if (v == SEQ_START_TOKEN)
seq_puts(seq, "Type Device Function\n");
else if ((!pt->af_packet_net || net_eq(pt->af_packet_net, seq_file_net(seq))) &&
(!pt->dev || net_eq(dev_net(pt->dev), seq_file_net(seq)))) {
if (pt->type == htons(ETH_P_ALL))
seq_puts(seq, "ALL ");
else
seq_printf(seq, "%04x", ntohs(pt->type));
seq_printf(seq, " %-8s %ps\n",
pt->dev ? pt->dev->name : "", pt->func);
}
return 0;
}
static const struct seq_operations ptype_seq_ops = {
.start = ptype_seq_start,
.next = ptype_seq_next,
.stop = ptype_seq_stop,
.show = ptype_seq_show,
};
static int __net_init dev_proc_net_init(struct net *net)
{
int rc = -ENOMEM;
if (!proc_create_net("dev", 0444, net->proc_net, &dev_seq_ops,
sizeof(struct seq_net_private)))
goto out;
if (!proc_create_seq("softnet_stat", 0444, net->proc_net,
&softnet_seq_ops))
goto out_dev;
if (!proc_create_net("ptype", 0444, net->proc_net, &ptype_seq_ops,
sizeof(struct seq_net_private)))
goto out_softnet;
if (wext_proc_init(net))
goto out_ptype;
rc = 0;
out:
return rc;
out_ptype:
remove_proc_entry("ptype", net->proc_net);
out_softnet:
remove_proc_entry("softnet_stat", net->proc_net);
out_dev:
remove_proc_entry("dev", net->proc_net);
goto out;
}
static void __net_exit dev_proc_net_exit(struct net *net)
{
wext_proc_exit(net);
remove_proc_entry("ptype", net->proc_net);
remove_proc_entry("softnet_stat", net->proc_net);
remove_proc_entry("dev", net->proc_net);
}
static struct pernet_operations __net_initdata dev_proc_ops = {
.init = dev_proc_net_init,
.exit = dev_proc_net_exit,
};
static int dev_mc_seq_show(struct seq_file *seq, void *v)
{
struct netdev_hw_addr *ha;
struct net_device *dev = v;
if (v == SEQ_START_TOKEN)
return 0;
netif_addr_lock_bh(dev);
netdev_for_each_mc_addr(ha, dev) {
seq_printf(seq, "%-4d %-15s %-5d %-5d %*phN\n",
dev->ifindex, dev->name,
ha->refcount, ha->global_use,
(int)dev->addr_len, ha->addr);
}
netif_addr_unlock_bh(dev);
return 0;
}
static const struct seq_operations dev_mc_seq_ops = {
.start = dev_seq_start,
.next = dev_seq_next,
.stop = dev_seq_stop,
.show = dev_mc_seq_show,
};
static int __net_init dev_mc_net_init(struct net *net)
{
if (!proc_create_net("dev_mcast", 0, net->proc_net, &dev_mc_seq_ops,
sizeof(struct seq_net_private)))
return -ENOMEM;
return 0;
}
static void __net_exit dev_mc_net_exit(struct net *net)
{
remove_proc_entry("dev_mcast", net->proc_net);
}
static struct pernet_operations __net_initdata dev_mc_net_ops = {
.init = dev_mc_net_init,
.exit = dev_mc_net_exit,
};
int __init dev_proc_init(void)
{
int ret = register_pernet_subsys(&dev_proc_ops);
if (!ret)
return register_pernet_subsys(&dev_mc_net_ops);
return ret;
}