linux-stable/net/rxrpc/proc.c
David Howells 5086d9a9df rxrpc: Move the cwnd degradation after transmitting packets
When we've gone for >1RTT without transmitting a packet, we should reduce
the ssthresh and cut the cwnd by half (as suggested in RFC2861 sec 3.1).

However, we may receive ACK packets in a batch and the first of these may
cut the cwnd, preventing further transmission, and each subsequent one cuts
the cwnd yet further, reducing it to the floor and killing performance.

Fix this by moving the cwnd reset to after doing the transmission and
resetting the base time such that we don't cut the cwnd by half again for
at least another RTT.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:43 +00:00

498 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/* /proc/net/ support for AF_RXRPC
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/module.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"
static const char *const rxrpc_conn_states[RXRPC_CONN__NR_STATES] = {
[RXRPC_CONN_UNUSED] = "Unused ",
[RXRPC_CONN_CLIENT] = "Client ",
[RXRPC_CONN_SERVICE_PREALLOC] = "SvPrealc",
[RXRPC_CONN_SERVICE_UNSECURED] = "SvUnsec ",
[RXRPC_CONN_SERVICE_CHALLENGING] = "SvChall ",
[RXRPC_CONN_SERVICE] = "SvSecure",
[RXRPC_CONN_REMOTELY_ABORTED] = "RmtAbort",
[RXRPC_CONN_LOCALLY_ABORTED] = "LocAbort",
};
/*
* generate a list of extant and dead calls in /proc/net/rxrpc_calls
*/
static void *rxrpc_call_seq_start(struct seq_file *seq, loff_t *_pos)
__acquires(rcu)
{
struct rxrpc_net *rxnet = rxrpc_net(seq_file_net(seq));
rcu_read_lock();
return seq_list_start_head_rcu(&rxnet->calls, *_pos);
}
static void *rxrpc_call_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct rxrpc_net *rxnet = rxrpc_net(seq_file_net(seq));
return seq_list_next_rcu(v, &rxnet->calls, pos);
}
static void rxrpc_call_seq_stop(struct seq_file *seq, void *v)
__releases(rcu)
{
rcu_read_unlock();
}
static int rxrpc_call_seq_show(struct seq_file *seq, void *v)
{
struct rxrpc_local *local;
struct rxrpc_call *call;
struct rxrpc_net *rxnet = rxrpc_net(seq_file_net(seq));
unsigned long timeout = 0;
rxrpc_seq_t acks_hard_ack;
char lbuff[50], rbuff[50];
u64 wtmp;
if (v == &rxnet->calls) {
seq_puts(seq,
"Proto Local "
" Remote "
" SvID ConnID CallID End Use State Abort "
" DebugId TxSeq TW RxSeq RW RxSerial CW RxTimo\n");
return 0;
}
call = list_entry(v, struct rxrpc_call, link);
local = call->local;
if (local)
sprintf(lbuff, "%pISpc", &local->srx.transport);
else
strcpy(lbuff, "no_local");
sprintf(rbuff, "%pISpc", &call->dest_srx.transport);
if (call->state != RXRPC_CALL_SERVER_PREALLOC) {
timeout = READ_ONCE(call->expect_rx_by);
timeout -= jiffies;
}
acks_hard_ack = READ_ONCE(call->acks_hard_ack);
wtmp = atomic64_read_acquire(&call->ackr_window);
seq_printf(seq,
"UDP %-47.47s %-47.47s %4x %08x %08x %s %3u"
" %-8.8s %08x %08x %08x %02x %08x %02x %08x %02x %06lx\n",
lbuff,
rbuff,
call->dest_srx.srx_service,
call->cid,
call->call_id,
rxrpc_is_service_call(call) ? "Svc" : "Clt",
refcount_read(&call->ref),
rxrpc_call_states[call->state],
call->abort_code,
call->debug_id,
acks_hard_ack, READ_ONCE(call->tx_top) - acks_hard_ack,
lower_32_bits(wtmp), upper_32_bits(wtmp) - lower_32_bits(wtmp),
call->rx_serial,
call->cong_cwnd,
timeout);
return 0;
}
const struct seq_operations rxrpc_call_seq_ops = {
.start = rxrpc_call_seq_start,
.next = rxrpc_call_seq_next,
.stop = rxrpc_call_seq_stop,
.show = rxrpc_call_seq_show,
};
/*
* generate a list of extant virtual connections in /proc/net/rxrpc_conns
*/
static void *rxrpc_connection_seq_start(struct seq_file *seq, loff_t *_pos)
__acquires(rxnet->conn_lock)
{
struct rxrpc_net *rxnet = rxrpc_net(seq_file_net(seq));
read_lock(&rxnet->conn_lock);
return seq_list_start_head(&rxnet->conn_proc_list, *_pos);
}
static void *rxrpc_connection_seq_next(struct seq_file *seq, void *v,
loff_t *pos)
{
struct rxrpc_net *rxnet = rxrpc_net(seq_file_net(seq));
return seq_list_next(v, &rxnet->conn_proc_list, pos);
}
static void rxrpc_connection_seq_stop(struct seq_file *seq, void *v)
__releases(rxnet->conn_lock)
{
struct rxrpc_net *rxnet = rxrpc_net(seq_file_net(seq));
read_unlock(&rxnet->conn_lock);
}
static int rxrpc_connection_seq_show(struct seq_file *seq, void *v)
{
struct rxrpc_connection *conn;
struct rxrpc_net *rxnet = rxrpc_net(seq_file_net(seq));
char lbuff[50], rbuff[50];
if (v == &rxnet->conn_proc_list) {
seq_puts(seq,
"Proto Local "
" Remote "
" SvID ConnID End Ref Act State Key "
" Serial ISerial CallId0 CallId1 CallId2 CallId3\n"
);
return 0;
}
conn = list_entry(v, struct rxrpc_connection, proc_link);
if (conn->state == RXRPC_CONN_SERVICE_PREALLOC) {
strcpy(lbuff, "no_local");
strcpy(rbuff, "no_connection");
goto print;
}
sprintf(lbuff, "%pISpc", &conn->local->srx.transport);
sprintf(rbuff, "%pISpc", &conn->peer->srx.transport);
print:
seq_printf(seq,
"UDP %-47.47s %-47.47s %4x %08x %s %3u %3d"
" %s %08x %08x %08x %08x %08x %08x %08x\n",
lbuff,
rbuff,
conn->service_id,
conn->proto.cid,
rxrpc_conn_is_service(conn) ? "Svc" : "Clt",
refcount_read(&conn->ref),
atomic_read(&conn->active),
rxrpc_conn_states[conn->state],
key_serial(conn->key),
atomic_read(&conn->serial),
conn->hi_serial,
conn->channels[0].call_id,
conn->channels[1].call_id,
conn->channels[2].call_id,
conn->channels[3].call_id);
return 0;
}
const struct seq_operations rxrpc_connection_seq_ops = {
.start = rxrpc_connection_seq_start,
.next = rxrpc_connection_seq_next,
.stop = rxrpc_connection_seq_stop,
.show = rxrpc_connection_seq_show,
};
/*
* generate a list of extant virtual peers in /proc/net/rxrpc/peers
*/
static int rxrpc_peer_seq_show(struct seq_file *seq, void *v)
{
struct rxrpc_peer *peer;
time64_t now;
char lbuff[50], rbuff[50];
if (v == SEQ_START_TOKEN) {
seq_puts(seq,
"Proto Local "
" Remote "
" Use SST MTU LastUse RTT RTO\n"
);
return 0;
}
peer = list_entry(v, struct rxrpc_peer, hash_link);
sprintf(lbuff, "%pISpc", &peer->local->srx.transport);
sprintf(rbuff, "%pISpc", &peer->srx.transport);
now = ktime_get_seconds();
seq_printf(seq,
"UDP %-47.47s %-47.47s %3u"
" %3u %5u %6llus %8u %8u\n",
lbuff,
rbuff,
refcount_read(&peer->ref),
peer->cong_ssthresh,
peer->mtu,
now - peer->last_tx_at,
peer->srtt_us >> 3,
jiffies_to_usecs(peer->rto_j));
return 0;
}
static void *rxrpc_peer_seq_start(struct seq_file *seq, loff_t *_pos)
__acquires(rcu)
{
struct rxrpc_net *rxnet = rxrpc_net(seq_file_net(seq));
unsigned int bucket, n;
unsigned int shift = 32 - HASH_BITS(rxnet->peer_hash);
void *p;
rcu_read_lock();
if (*_pos >= UINT_MAX)
return NULL;
n = *_pos & ((1U << shift) - 1);
bucket = *_pos >> shift;
for (;;) {
if (bucket >= HASH_SIZE(rxnet->peer_hash)) {
*_pos = UINT_MAX;
return NULL;
}
if (n == 0) {
if (bucket == 0)
return SEQ_START_TOKEN;
*_pos += 1;
n++;
}
p = seq_hlist_start_rcu(&rxnet->peer_hash[bucket], n - 1);
if (p)
return p;
bucket++;
n = 1;
*_pos = (bucket << shift) | n;
}
}
static void *rxrpc_peer_seq_next(struct seq_file *seq, void *v, loff_t *_pos)
{
struct rxrpc_net *rxnet = rxrpc_net(seq_file_net(seq));
unsigned int bucket, n;
unsigned int shift = 32 - HASH_BITS(rxnet->peer_hash);
void *p;
if (*_pos >= UINT_MAX)
return NULL;
bucket = *_pos >> shift;
p = seq_hlist_next_rcu(v, &rxnet->peer_hash[bucket], _pos);
if (p)
return p;
for (;;) {
bucket++;
n = 1;
*_pos = (bucket << shift) | n;
if (bucket >= HASH_SIZE(rxnet->peer_hash)) {
*_pos = UINT_MAX;
return NULL;
}
if (n == 0) {
*_pos += 1;
n++;
}
p = seq_hlist_start_rcu(&rxnet->peer_hash[bucket], n - 1);
if (p)
return p;
}
}
static void rxrpc_peer_seq_stop(struct seq_file *seq, void *v)
__releases(rcu)
{
rcu_read_unlock();
}
const struct seq_operations rxrpc_peer_seq_ops = {
.start = rxrpc_peer_seq_start,
.next = rxrpc_peer_seq_next,
.stop = rxrpc_peer_seq_stop,
.show = rxrpc_peer_seq_show,
};
/*
* Generate a list of extant virtual local endpoints in /proc/net/rxrpc/locals
*/
static int rxrpc_local_seq_show(struct seq_file *seq, void *v)
{
struct rxrpc_local *local;
char lbuff[50];
if (v == SEQ_START_TOKEN) {
seq_puts(seq,
"Proto Local "
" Use Act RxQ\n");
return 0;
}
local = hlist_entry(v, struct rxrpc_local, link);
sprintf(lbuff, "%pISpc", &local->srx.transport);
seq_printf(seq,
"UDP %-47.47s %3u %3u %3u\n",
lbuff,
refcount_read(&local->ref),
atomic_read(&local->active_users),
local->rx_queue.qlen);
return 0;
}
static void *rxrpc_local_seq_start(struct seq_file *seq, loff_t *_pos)
__acquires(rcu)
{
struct rxrpc_net *rxnet = rxrpc_net(seq_file_net(seq));
unsigned int n;
rcu_read_lock();
if (*_pos >= UINT_MAX)
return NULL;
n = *_pos;
if (n == 0)
return SEQ_START_TOKEN;
return seq_hlist_start_rcu(&rxnet->local_endpoints, n - 1);
}
static void *rxrpc_local_seq_next(struct seq_file *seq, void *v, loff_t *_pos)
{
struct rxrpc_net *rxnet = rxrpc_net(seq_file_net(seq));
if (*_pos >= UINT_MAX)
return NULL;
return seq_hlist_next_rcu(v, &rxnet->local_endpoints, _pos);
}
static void rxrpc_local_seq_stop(struct seq_file *seq, void *v)
__releases(rcu)
{
rcu_read_unlock();
}
const struct seq_operations rxrpc_local_seq_ops = {
.start = rxrpc_local_seq_start,
.next = rxrpc_local_seq_next,
.stop = rxrpc_local_seq_stop,
.show = rxrpc_local_seq_show,
};
/*
* Display stats in /proc/net/rxrpc/stats
*/
int rxrpc_stats_show(struct seq_file *seq, void *v)
{
struct rxrpc_net *rxnet = rxrpc_net(seq_file_single_net(seq));
seq_printf(seq,
"Data : send=%u sendf=%u fail=%u\n",
atomic_read(&rxnet->stat_tx_data_send),
atomic_read(&rxnet->stat_tx_data_send_frag),
atomic_read(&rxnet->stat_tx_data_send_fail));
seq_printf(seq,
"Data-Tx : nr=%u retrans=%u uf=%u cwr=%u\n",
atomic_read(&rxnet->stat_tx_data),
atomic_read(&rxnet->stat_tx_data_retrans),
atomic_read(&rxnet->stat_tx_data_underflow),
atomic_read(&rxnet->stat_tx_data_cwnd_reset));
seq_printf(seq,
"Data-Rx : nr=%u reqack=%u jumbo=%u\n",
atomic_read(&rxnet->stat_rx_data),
atomic_read(&rxnet->stat_rx_data_reqack),
atomic_read(&rxnet->stat_rx_data_jumbo));
seq_printf(seq,
"Ack : fill=%u send=%u skip=%u\n",
atomic_read(&rxnet->stat_tx_ack_fill),
atomic_read(&rxnet->stat_tx_ack_send),
atomic_read(&rxnet->stat_tx_ack_skip));
seq_printf(seq,
"Ack-Tx : req=%u dup=%u oos=%u exw=%u nos=%u png=%u prs=%u dly=%u idl=%u\n",
atomic_read(&rxnet->stat_tx_acks[RXRPC_ACK_REQUESTED]),
atomic_read(&rxnet->stat_tx_acks[RXRPC_ACK_DUPLICATE]),
atomic_read(&rxnet->stat_tx_acks[RXRPC_ACK_OUT_OF_SEQUENCE]),
atomic_read(&rxnet->stat_tx_acks[RXRPC_ACK_EXCEEDS_WINDOW]),
atomic_read(&rxnet->stat_tx_acks[RXRPC_ACK_NOSPACE]),
atomic_read(&rxnet->stat_tx_acks[RXRPC_ACK_PING]),
atomic_read(&rxnet->stat_tx_acks[RXRPC_ACK_PING_RESPONSE]),
atomic_read(&rxnet->stat_tx_acks[RXRPC_ACK_DELAY]),
atomic_read(&rxnet->stat_tx_acks[RXRPC_ACK_IDLE]));
seq_printf(seq,
"Ack-Rx : req=%u dup=%u oos=%u exw=%u nos=%u png=%u prs=%u dly=%u idl=%u\n",
atomic_read(&rxnet->stat_rx_acks[RXRPC_ACK_REQUESTED]),
atomic_read(&rxnet->stat_rx_acks[RXRPC_ACK_DUPLICATE]),
atomic_read(&rxnet->stat_rx_acks[RXRPC_ACK_OUT_OF_SEQUENCE]),
atomic_read(&rxnet->stat_rx_acks[RXRPC_ACK_EXCEEDS_WINDOW]),
atomic_read(&rxnet->stat_rx_acks[RXRPC_ACK_NOSPACE]),
atomic_read(&rxnet->stat_rx_acks[RXRPC_ACK_PING]),
atomic_read(&rxnet->stat_rx_acks[RXRPC_ACK_PING_RESPONSE]),
atomic_read(&rxnet->stat_rx_acks[RXRPC_ACK_DELAY]),
atomic_read(&rxnet->stat_rx_acks[RXRPC_ACK_IDLE]));
seq_printf(seq,
"Why-Req-A: acklost=%u already=%u mrtt=%u ortt=%u\n",
atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_ack_lost]),
atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_already_on]),
atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_more_rtt]),
atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_old_rtt]));
seq_printf(seq,
"Why-Req-A: nolast=%u retx=%u slows=%u smtxw=%u\n",
atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_no_srv_last]),
atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_retrans]),
atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_slow_start]),
atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_small_txwin]));
seq_printf(seq,
"Buffers : txb=%u rxb=%u\n",
atomic_read(&rxrpc_nr_txbuf),
atomic_read(&rxrpc_n_rx_skbs));
seq_printf(seq,
"IO-thread: loops=%u\n",
atomic_read(&rxnet->stat_io_loop));
return 0;
}
/*
* Clear stats if /proc/net/rxrpc/stats is written to.
*/
int rxrpc_stats_clear(struct file *file, char *buf, size_t size)
{
struct seq_file *m = file->private_data;
struct rxrpc_net *rxnet = rxrpc_net(seq_file_single_net(m));
if (size > 1 || (size == 1 && buf[0] != '\n'))
return -EINVAL;
atomic_set(&rxnet->stat_tx_data, 0);
atomic_set(&rxnet->stat_tx_data_retrans, 0);
atomic_set(&rxnet->stat_tx_data_underflow, 0);
atomic_set(&rxnet->stat_tx_data_cwnd_reset, 0);
atomic_set(&rxnet->stat_tx_data_send, 0);
atomic_set(&rxnet->stat_tx_data_send_frag, 0);
atomic_set(&rxnet->stat_tx_data_send_fail, 0);
atomic_set(&rxnet->stat_rx_data, 0);
atomic_set(&rxnet->stat_rx_data_reqack, 0);
atomic_set(&rxnet->stat_rx_data_jumbo, 0);
atomic_set(&rxnet->stat_tx_ack_fill, 0);
atomic_set(&rxnet->stat_tx_ack_send, 0);
atomic_set(&rxnet->stat_tx_ack_skip, 0);
memset(&rxnet->stat_tx_acks, 0, sizeof(rxnet->stat_tx_acks));
memset(&rxnet->stat_rx_acks, 0, sizeof(rxnet->stat_rx_acks));
memset(&rxnet->stat_why_req_ack, 0, sizeof(rxnet->stat_why_req_ack));
atomic_set(&rxnet->stat_io_loop, 0);
return size;
}