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linux/net/mac80211/debugfs.c
Kan Yan 3ace10f5b5 mac80211: Implement Airtime-based Queue Limit (AQL) 
In order for the Fq_CoDel algorithm integrated in mac80211 layer to operate
effectively to control excessive queueing latency, the CoDel algorithm
requires an accurate measure of how long packets stays in the queue, AKA
sojourn time. The sojourn time measured at the mac80211 layer doesn't
include queueing latency in the lower layer (firmware/hardware) and CoDel
expects lower layer to have a short queue. However, most 802.11ac chipsets
offload tasks such TX aggregation to firmware or hardware, thus have a deep
lower layer queue.

Without a mechanism to control the lower layer queue size, packets only
stay in mac80211 layer transiently before being sent to firmware queue.
As a result, the sojourn time measured by CoDel in the mac80211 layer is
almost always lower than the CoDel latency target, hence CoDel does little
to control the latency, even when the lower layer queue causes excessive
latency.

The Byte Queue Limits (BQL) mechanism is commonly used to address the
similar issue with wired network interface. However, this method cannot be
applied directly to the wireless network interface. "Bytes" is not a
suitable measure of queue depth in the wireless network, as the data rate
can vary dramatically from station to station in the same network, from a
few Mbps to over Gbps.

This patch implements an Airtime-based Queue Limit (AQL) to make CoDel work
effectively with wireless drivers that utilized firmware/hardware
offloading. AQL allows each txq to release just enough packets to the lower
layer to form 1-2 large aggregations to keep hardware fully utilized and
retains the rest of the frames in mac80211 layer to be controlled by the
CoDel algorithm.

Signed-off-by: Kan Yan <kyan@google.com>
[ Toke: Keep API to set pending airtime internal, fix nits in commit msg ]
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20191119060610.76681-4-kyan@google.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2019-11-22 13:36:25 +01:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* mac80211 debugfs for wireless PHYs
*
* Copyright 2007 Johannes Berg <johannes@sipsolutions.net>
* Copyright 2013-2014 Intel Mobile Communications GmbH
* Copyright (C) 2018 - 2019 Intel Corporation
*/
#include <linux/debugfs.h>
#include <linux/rtnetlink.h>
#include <linux/vmalloc.h>
#include "ieee80211_i.h"
#include "driver-ops.h"
#include "rate.h"
#include "debugfs.h"
#define DEBUGFS_FORMAT_BUFFER_SIZE 100
int mac80211_format_buffer(char __user *userbuf, size_t count,
loff_t *ppos, char *fmt, ...)
{
va_list args;
char buf[DEBUGFS_FORMAT_BUFFER_SIZE];
int res;
va_start(args, fmt);
res = vscnprintf(buf, sizeof(buf), fmt, args);
va_end(args);
return simple_read_from_buffer(userbuf, count, ppos, buf, res);
}
#define DEBUGFS_READONLY_FILE_FN(name, fmt, value...) \
static ssize_t name## _read(struct file *file, char __user *userbuf, \
size_t count, loff_t *ppos) \
{ \
struct ieee80211_local *local = file->private_data; \
\
return mac80211_format_buffer(userbuf, count, ppos, \
fmt "\n", ##value); \
}
#define DEBUGFS_READONLY_FILE_OPS(name) \
static const struct file_operations name## _ops = { \
.read = name## _read, \
.open = simple_open, \
.llseek = generic_file_llseek, \
};
#define DEBUGFS_READONLY_FILE(name, fmt, value...) \
DEBUGFS_READONLY_FILE_FN(name, fmt, value) \
DEBUGFS_READONLY_FILE_OPS(name)
#define DEBUGFS_ADD(name) \
debugfs_create_file(#name, 0400, phyd, local, &name## _ops);
#define DEBUGFS_ADD_MODE(name, mode) \
debugfs_create_file(#name, mode, phyd, local, &name## _ops);
DEBUGFS_READONLY_FILE(hw_conf, "%x",
local->hw.conf.flags);
DEBUGFS_READONLY_FILE(user_power, "%d",
local->user_power_level);
DEBUGFS_READONLY_FILE(power, "%d",
local->hw.conf.power_level);
DEBUGFS_READONLY_FILE(total_ps_buffered, "%d",
local->total_ps_buffered);
DEBUGFS_READONLY_FILE(wep_iv, "%#08x",
local->wep_iv & 0xffffff);
DEBUGFS_READONLY_FILE(rate_ctrl_alg, "%s",
local->rate_ctrl ? local->rate_ctrl->ops->name : "hw/driver");
static ssize_t aqm_read(struct file *file,
char __user *user_buf,
size_t count,
loff_t *ppos)
{
struct ieee80211_local *local = file->private_data;
struct fq *fq = &local->fq;
char buf[200];
int len = 0;
spin_lock_bh(&local->fq.lock);
rcu_read_lock();
len = scnprintf(buf, sizeof(buf),
"access name value\n"
"R fq_flows_cnt %u\n"
"R fq_backlog %u\n"
"R fq_overlimit %u\n"
"R fq_overmemory %u\n"
"R fq_collisions %u\n"
"R fq_memory_usage %u\n"
"RW fq_memory_limit %u\n"
"RW fq_limit %u\n"
"RW fq_quantum %u\n",
fq->flows_cnt,
fq->backlog,
fq->overmemory,
fq->overlimit,
fq->collisions,
fq->memory_usage,
fq->memory_limit,
fq->limit,
fq->quantum);
rcu_read_unlock();
spin_unlock_bh(&local->fq.lock);
return simple_read_from_buffer(user_buf, count, ppos,
buf, len);
}
static ssize_t aqm_write(struct file *file,
const char __user *user_buf,
size_t count,
loff_t *ppos)
{
struct ieee80211_local *local = file->private_data;
char buf[100];
size_t len;
if (count > sizeof(buf))
return -EINVAL;
if (copy_from_user(buf, user_buf, count))
return -EFAULT;
buf[sizeof(buf) - 1] = '\0';
len = strlen(buf);
if (len > 0 && buf[len-1] == '\n')
buf[len-1] = 0;
if (sscanf(buf, "fq_limit %u", &local->fq.limit) == 1)
return count;
else if (sscanf(buf, "fq_memory_limit %u", &local->fq.memory_limit) == 1)
return count;
else if (sscanf(buf, "fq_quantum %u", &local->fq.quantum) == 1)
return count;
return -EINVAL;
}
static const struct file_operations aqm_ops = {
.write = aqm_write,
.read = aqm_read,
.open = simple_open,
.llseek = default_llseek,
};
static ssize_t aql_txq_limit_read(struct file *file,
char __user *user_buf,
size_t count,
loff_t *ppos)
{
struct ieee80211_local *local = file->private_data;
char buf[400];
int len = 0;
len = scnprintf(buf, sizeof(buf),
"AC AQL limit low AQL limit high\n"
"VO %u %u\n"
"VI %u %u\n"
"BE %u %u\n"
"BK %u %u\n",
local->aql_txq_limit_low[IEEE80211_AC_VO],
local->aql_txq_limit_high[IEEE80211_AC_VO],
local->aql_txq_limit_low[IEEE80211_AC_VI],
local->aql_txq_limit_high[IEEE80211_AC_VI],
local->aql_txq_limit_low[IEEE80211_AC_BE],
local->aql_txq_limit_high[IEEE80211_AC_BE],
local->aql_txq_limit_low[IEEE80211_AC_BK],
local->aql_txq_limit_high[IEEE80211_AC_BK]);
return simple_read_from_buffer(user_buf, count, ppos,
buf, len);
}
static ssize_t aql_txq_limit_write(struct file *file,
const char __user *user_buf,
size_t count,
loff_t *ppos)
{
struct ieee80211_local *local = file->private_data;
char buf[100];
size_t len;
u32 ac, q_limit_low, q_limit_high, q_limit_low_old, q_limit_high_old;
struct sta_info *sta;
if (count > sizeof(buf))
return -EINVAL;
if (copy_from_user(buf, user_buf, count))
return -EFAULT;
buf[sizeof(buf) - 1] = 0;
len = strlen(buf);
if (len > 0 && buf[len - 1] == '\n')
buf[len - 1] = 0;
if (sscanf(buf, "%u %u %u", &ac, &q_limit_low, &q_limit_high) != 3)
return -EINVAL;
if (ac >= IEEE80211_NUM_ACS)
return -EINVAL;
q_limit_low_old = local->aql_txq_limit_low[ac];
q_limit_high_old = local->aql_txq_limit_high[ac];
local->aql_txq_limit_low[ac] = q_limit_low;
local->aql_txq_limit_high[ac] = q_limit_high;
mutex_lock(&local->sta_mtx);
list_for_each_entry(sta, &local->sta_list, list) {
/* If a sta has customized queue limits, keep it */
if (sta->airtime[ac].aql_limit_low == q_limit_low_old &&
sta->airtime[ac].aql_limit_high == q_limit_high_old) {
sta->airtime[ac].aql_limit_low = q_limit_low;
sta->airtime[ac].aql_limit_high = q_limit_high;
}
}
mutex_unlock(&local->sta_mtx);
return count;
}
static const struct file_operations aql_txq_limit_ops = {
.write = aql_txq_limit_write,
.read = aql_txq_limit_read,
.open = simple_open,
.llseek = default_llseek,
};
static ssize_t force_tx_status_read(struct file *file,
char __user *user_buf,
size_t count,
loff_t *ppos)
{
struct ieee80211_local *local = file->private_data;
char buf[3];
int len = 0;
len = scnprintf(buf, sizeof(buf), "%d\n", (int)local->force_tx_status);
return simple_read_from_buffer(user_buf, count, ppos,
buf, len);
}
static ssize_t force_tx_status_write(struct file *file,
const char __user *user_buf,
size_t count,
loff_t *ppos)
{
struct ieee80211_local *local = file->private_data;
char buf[3];
size_t len;
if (count > sizeof(buf))
return -EINVAL;
if (copy_from_user(buf, user_buf, count))
return -EFAULT;
buf[sizeof(buf) - 1] = '\0';
len = strlen(buf);
if (len > 0 && buf[len - 1] == '\n')
buf[len - 1] = 0;
if (buf[0] == '0' && buf[1] == '\0')
local->force_tx_status = 0;
else if (buf[0] == '1' && buf[1] == '\0')
local->force_tx_status = 1;
else
return -EINVAL;
return count;
}
static const struct file_operations force_tx_status_ops = {
.write = force_tx_status_write,
.read = force_tx_status_read,
.open = simple_open,
.llseek = default_llseek,
};
#ifdef CONFIG_PM
static ssize_t reset_write(struct file *file, const char __user *user_buf,
size_t count, loff_t *ppos)
{
struct ieee80211_local *local = file->private_data;
rtnl_lock();
__ieee80211_suspend(&local->hw, NULL);
__ieee80211_resume(&local->hw);
rtnl_unlock();
return count;
}
static const struct file_operations reset_ops = {
.write = reset_write,
.open = simple_open,
.llseek = noop_llseek,
};
#endif
static const char *hw_flag_names[] = {
#define FLAG(F) [IEEE80211_HW_##F] = #F
FLAG(HAS_RATE_CONTROL),
FLAG(RX_INCLUDES_FCS),
FLAG(HOST_BROADCAST_PS_BUFFERING),
FLAG(SIGNAL_UNSPEC),
FLAG(SIGNAL_DBM),
FLAG(NEED_DTIM_BEFORE_ASSOC),
FLAG(SPECTRUM_MGMT),
FLAG(AMPDU_AGGREGATION),
FLAG(SUPPORTS_PS),
FLAG(PS_NULLFUNC_STACK),
FLAG(SUPPORTS_DYNAMIC_PS),
FLAG(MFP_CAPABLE),
FLAG(WANT_MONITOR_VIF),
FLAG(NO_AUTO_VIF),
FLAG(SW_CRYPTO_CONTROL),
FLAG(SUPPORT_FAST_XMIT),
FLAG(REPORTS_TX_ACK_STATUS),
FLAG(CONNECTION_MONITOR),
FLAG(QUEUE_CONTROL),
FLAG(SUPPORTS_PER_STA_GTK),
FLAG(AP_LINK_PS),
FLAG(TX_AMPDU_SETUP_IN_HW),
FLAG(SUPPORTS_RC_TABLE),
FLAG(P2P_DEV_ADDR_FOR_INTF),
FLAG(TIMING_BEACON_ONLY),
FLAG(SUPPORTS_HT_CCK_RATES),
FLAG(CHANCTX_STA_CSA),
FLAG(SUPPORTS_CLONED_SKBS),
FLAG(SINGLE_SCAN_ON_ALL_BANDS),
FLAG(TDLS_WIDER_BW),
FLAG(SUPPORTS_AMSDU_IN_AMPDU),
FLAG(BEACON_TX_STATUS),
FLAG(NEEDS_UNIQUE_STA_ADDR),
FLAG(SUPPORTS_REORDERING_BUFFER),
FLAG(USES_RSS),
FLAG(TX_AMSDU),
FLAG(TX_FRAG_LIST),
FLAG(REPORTS_LOW_ACK),
FLAG(SUPPORTS_TX_FRAG),
FLAG(SUPPORTS_TDLS_BUFFER_STA),
FLAG(DEAUTH_NEED_MGD_TX_PREP),
FLAG(DOESNT_SUPPORT_QOS_NDP),
FLAG(BUFF_MMPDU_TXQ),
FLAG(SUPPORTS_VHT_EXT_NSS_BW),
FLAG(STA_MMPDU_TXQ),
FLAG(TX_STATUS_NO_AMPDU_LEN),
FLAG(SUPPORTS_MULTI_BSSID),
FLAG(SUPPORTS_ONLY_HE_MULTI_BSSID),
FLAG(AMPDU_KEYBORDER_SUPPORT),
#undef FLAG
};
static ssize_t hwflags_read(struct file *file, char __user *user_buf,
size_t count, loff_t *ppos)
{
struct ieee80211_local *local = file->private_data;
size_t bufsz = 30 * NUM_IEEE80211_HW_FLAGS;
char *buf = kzalloc(bufsz, GFP_KERNEL);
char *pos = buf, *end = buf + bufsz - 1;
ssize_t rv;
int i;
if (!buf)
return -ENOMEM;
/* fail compilation if somebody adds or removes
* a flag without updating the name array above
*/
BUILD_BUG_ON(ARRAY_SIZE(hw_flag_names) != NUM_IEEE80211_HW_FLAGS);
for (i = 0; i < NUM_IEEE80211_HW_FLAGS; i++) {
if (test_bit(i, local->hw.flags))
pos += scnprintf(pos, end - pos, "%s\n",
hw_flag_names[i]);
}
rv = simple_read_from_buffer(user_buf, count, ppos, buf, strlen(buf));
kfree(buf);
return rv;
}
static ssize_t misc_read(struct file *file, char __user *user_buf,
size_t count, loff_t *ppos)
{
struct ieee80211_local *local = file->private_data;
/* Max len of each line is 16 characters, plus 9 for 'pending:\n' */
size_t bufsz = IEEE80211_MAX_QUEUES * 16 + 9;
char *buf;
char *pos, *end;
ssize_t rv;
int i;
int ln;
buf = kzalloc(bufsz, GFP_KERNEL);
if (!buf)
return -ENOMEM;
pos = buf;
end = buf + bufsz - 1;
pos += scnprintf(pos, end - pos, "pending:\n");
for (i = 0; i < IEEE80211_MAX_QUEUES; i++) {
ln = skb_queue_len(&local->pending[i]);
pos += scnprintf(pos, end - pos, "[%i] %d\n",
i, ln);
}
rv = simple_read_from_buffer(user_buf, count, ppos, buf, strlen(buf));
kfree(buf);
return rv;
}
static ssize_t queues_read(struct file *file, char __user *user_buf,
size_t count, loff_t *ppos)
{
struct ieee80211_local *local = file->private_data;
unsigned long flags;
char buf[IEEE80211_MAX_QUEUES * 20];
int q, res = 0;
spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
for (q = 0; q < local->hw.queues; q++)
res += sprintf(buf + res, "%02d: %#.8lx/%d\n", q,
local->queue_stop_reasons[q],
skb_queue_len(&local->pending[q]));
spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
return simple_read_from_buffer(user_buf, count, ppos, buf, res);
}
DEBUGFS_READONLY_FILE_OPS(hwflags);
DEBUGFS_READONLY_FILE_OPS(queues);
DEBUGFS_READONLY_FILE_OPS(misc);
/* statistics stuff */
static ssize_t format_devstat_counter(struct ieee80211_local *local,
char __user *userbuf,
size_t count, loff_t *ppos,
int (*printvalue)(struct ieee80211_low_level_stats *stats, char *buf,
int buflen))
{
struct ieee80211_low_level_stats stats;
char buf[20];
int res;
rtnl_lock();
res = drv_get_stats(local, &stats);
rtnl_unlock();
if (res)
return res;
res = printvalue(&stats, buf, sizeof(buf));
return simple_read_from_buffer(userbuf, count, ppos, buf, res);
}
#define DEBUGFS_DEVSTATS_FILE(name) \
static int print_devstats_##name(struct ieee80211_low_level_stats *stats,\
char *buf, int buflen) \
{ \
return scnprintf(buf, buflen, "%u\n", stats->name); \
} \
static ssize_t stats_ ##name## _read(struct file *file, \
char __user *userbuf, \
size_t count, loff_t *ppos) \
{ \
return format_devstat_counter(file->private_data, \
userbuf, \
count, \
ppos, \
print_devstats_##name); \
} \
\
static const struct file_operations stats_ ##name## _ops = { \
.read = stats_ ##name## _read, \
.open = simple_open, \
.llseek = generic_file_llseek, \
};
#define DEBUGFS_STATS_ADD(name) \
debugfs_create_u32(#name, 0400, statsd, &local->name);
#define DEBUGFS_DEVSTATS_ADD(name) \
debugfs_create_file(#name, 0400, statsd, local, &stats_ ##name## _ops);
DEBUGFS_DEVSTATS_FILE(dot11ACKFailureCount);
DEBUGFS_DEVSTATS_FILE(dot11RTSFailureCount);
DEBUGFS_DEVSTATS_FILE(dot11FCSErrorCount);
DEBUGFS_DEVSTATS_FILE(dot11RTSSuccessCount);
void debugfs_hw_add(struct ieee80211_local *local)
{
struct dentry *phyd = local->hw.wiphy->debugfsdir;
struct dentry *statsd;
if (!phyd)
return;
local->debugfs.keys = debugfs_create_dir("keys", phyd);
DEBUGFS_ADD(total_ps_buffered);
DEBUGFS_ADD(wep_iv);
DEBUGFS_ADD(rate_ctrl_alg);
DEBUGFS_ADD(queues);
DEBUGFS_ADD(misc);
#ifdef CONFIG_PM
DEBUGFS_ADD_MODE(reset, 0200);
#endif
DEBUGFS_ADD(hwflags);
DEBUGFS_ADD(user_power);
DEBUGFS_ADD(power);
DEBUGFS_ADD(hw_conf);
DEBUGFS_ADD_MODE(force_tx_status, 0600);
if (local->ops->wake_tx_queue)
DEBUGFS_ADD_MODE(aqm, 0600);
debugfs_create_u16("airtime_flags", 0600,
phyd, &local->airtime_flags);
DEBUGFS_ADD(aql_txq_limit);
debugfs_create_u32("aql_threshold", 0600,
phyd, &local->aql_threshold);
statsd = debugfs_create_dir("statistics", phyd);
/* if the dir failed, don't put all the other things into the root! */
if (!statsd)
return;
#ifdef CONFIG_MAC80211_DEBUG_COUNTERS
DEBUGFS_STATS_ADD(dot11TransmittedFragmentCount);
DEBUGFS_STATS_ADD(dot11MulticastTransmittedFrameCount);
DEBUGFS_STATS_ADD(dot11FailedCount);
DEBUGFS_STATS_ADD(dot11RetryCount);
DEBUGFS_STATS_ADD(dot11MultipleRetryCount);
DEBUGFS_STATS_ADD(dot11FrameDuplicateCount);
DEBUGFS_STATS_ADD(dot11ReceivedFragmentCount);
DEBUGFS_STATS_ADD(dot11MulticastReceivedFrameCount);
DEBUGFS_STATS_ADD(dot11TransmittedFrameCount);
DEBUGFS_STATS_ADD(tx_handlers_drop);
DEBUGFS_STATS_ADD(tx_handlers_queued);
DEBUGFS_STATS_ADD(tx_handlers_drop_wep);
DEBUGFS_STATS_ADD(tx_handlers_drop_not_assoc);
DEBUGFS_STATS_ADD(tx_handlers_drop_unauth_port);
DEBUGFS_STATS_ADD(rx_handlers_drop);
DEBUGFS_STATS_ADD(rx_handlers_queued);
DEBUGFS_STATS_ADD(rx_handlers_drop_nullfunc);
DEBUGFS_STATS_ADD(rx_handlers_drop_defrag);
DEBUGFS_STATS_ADD(tx_expand_skb_head);
DEBUGFS_STATS_ADD(tx_expand_skb_head_cloned);
DEBUGFS_STATS_ADD(rx_expand_skb_head_defrag);
DEBUGFS_STATS_ADD(rx_handlers_fragments);
DEBUGFS_STATS_ADD(tx_status_drop);
#endif
DEBUGFS_DEVSTATS_ADD(dot11ACKFailureCount);
DEBUGFS_DEVSTATS_ADD(dot11RTSFailureCount);
DEBUGFS_DEVSTATS_ADD(dot11FCSErrorCount);
DEBUGFS_DEVSTATS_ADD(dot11RTSSuccessCount);
}
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