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dropmon: add ability to detect when hardware dropsrxpackets

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Patch to add the ability to detect drops in hardware interfaces via dropwatch.
Adds a tracepoint to net_rx_action to signal everytime a napi instance is
polled.  The dropmon code then periodically checks to see if the rx_frames
counter has changed, and if so, adds a drop notification to the netlink
protocol, using the reserved all-0's vector to indicate the drop location was in
hardware, rather than somewhere in the code.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>

 include/linux/net_dropmon.h |    8 ++
 include/trace/napi.h        |   11 +++
 net/core/dev.c              |    5 +
 net/core/drop_monitor.c     |  124 ++++++++++++++++++++++++++++++++++++++++++--
 net/core/net-traces.c       |    4 +
 net/core/netpoll.c          |    2
 6 files changed, 149 insertions(+), 5 deletions(-)
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Neil Horman 2009-05-21 07:36:08 +00:00 committed by David S. Miller
parent d95ed9275e
commit 4ea7e38696
6 changed files with 149 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
include/linux/net_dropmon.h
View File

@ -2,12 +2,20 @@
#define __NET_DROPMON_H
#include <linux/netlink.h>
#include <linux/types.h>
struct net_dm_drop_point {
__u8 pc[8];
__u32 count;
};
#define is_drop_point_hw(x) do {\
int ____i, ____j;\
for (____i = 0; ____i < 8; i ____i++)\
____j |= x[____i];\
____j;\
} while (0)
#define NET_DM_CFG_VERSION 0
#define NET_DM_CFG_ALERT_COUNT 1
#define NET_DM_CFG_ALERT_DELAY 2

11
include/trace/napi.h Normal file
View File

@ -0,0 +1,11 @@
#ifndef _TRACE_NAPI_H_
#define _TRACE_NAPI_H_
#include <linux/netdevice.h>
#include <linux/tracepoint.h>
DECLARE_TRACE(napi_poll,
TP_PROTO(struct napi_struct *napi),
TP_ARGS(napi));
#endif

5
net/core/dev.c
View File

@ -126,6 +126,7 @@
#include <linux/in.h>
#include <linux/jhash.h>
#include <linux/random.h>
#include <trace/napi.h>
#include "net-sysfs.h"
@ -2771,8 +2772,10 @@ static void net_rx_action(struct softirq_action *h)
* accidently calling ->poll() when NAPI is not scheduled.
*/
work = 0;
if (test_bit(NAPI_STATE_SCHED, &n->state))
if (test_bit(NAPI_STATE_SCHED, &n->state)) {
work = n->poll(n, weight);
trace_napi_poll(n);
}
WARN_ON_ONCE(work > weight);

124
net/core/drop_monitor.c
View File

@ -22,8 +22,10 @@
#include <linux/timer.h>
#include <linux/bitops.h>
#include <net/genetlink.h>
#include <net/netevent.h>
#include <trace/skb.h>
#include <trace/napi.h>
#include <asm/unaligned.h>
@ -38,7 +40,8 @@ static void send_dm_alert(struct work_struct *unused);
* and the work handle that will send up
* netlink alerts
*/
struct sock *dm_sock;
static int trace_state = TRACE_OFF;
static spinlock_t trace_state_lock = SPIN_LOCK_UNLOCKED;
struct per_cpu_dm_data {
struct work_struct dm_alert_work;
@ -47,6 +50,13 @@ struct per_cpu_dm_data {
struct timer_list send_timer;
};
struct dm_hw_stat_delta {
struct net_device *dev;
struct list_head list;
struct rcu_head rcu;
unsigned long last_drop_val;
};
static struct genl_family net_drop_monitor_family = {
.id = GENL_ID_GENERATE,
.hdrsize = 0,
@ -59,7 +69,8 @@ static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data);
static int dm_hit_limit = 64;
static int dm_delay = 1;
static unsigned long dm_hw_check_delta = 2*HZ;
static LIST_HEAD(hw_stats_list);
static void reset_per_cpu_data(struct per_cpu_dm_data *data)
{
@ -115,7 +126,7 @@ static void sched_send_work(unsigned long unused)
schedule_work(&data->dm_alert_work);
}
static void trace_kfree_skb_hit(struct sk_buff *skb, void *location)
static void trace_drop_common(struct sk_buff *skb, void *location)
{
struct net_dm_alert_msg *msg;
struct nlmsghdr *nlh;
@ -159,24 +170,80 @@ out:
return;
}
static void trace_kfree_skb_hit(struct sk_buff *skb, void *location)
{
trace_drop_common(skb, location);
}
static void trace_napi_poll_hit(struct napi_struct *napi)
{
struct dm_hw_stat_delta *new_stat;
/*
* Ratelimit our check time to dm_hw_check_delta jiffies
*/
if (!time_after(jiffies, napi->dev->last_rx + dm_hw_check_delta))
return;
rcu_read_lock();
list_for_each_entry_rcu(new_stat, &hw_stats_list, list) {
if ((new_stat->dev == napi->dev) &&
(napi->dev->stats.rx_dropped != new_stat->last_drop_val)) {
trace_drop_common(NULL, NULL);
new_stat->last_drop_val = napi->dev->stats.rx_dropped;
break;
}
}
rcu_read_unlock();
}
static void free_dm_hw_stat(struct rcu_head *head)
{
struct dm_hw_stat_delta *n;
n = container_of(head, struct dm_hw_stat_delta, rcu);
kfree(n);
}
static int set_all_monitor_traces(int state)
{
int rc = 0;
struct dm_hw_stat_delta *new_stat = NULL;
struct dm_hw_stat_delta *temp;
spin_lock(&trace_state_lock);
switch (state) {
case TRACE_ON:
rc |= register_trace_kfree_skb(trace_kfree_skb_hit);
rc |= register_trace_napi_poll(trace_napi_poll_hit);
break;
case TRACE_OFF:
rc |= unregister_trace_kfree_skb(trace_kfree_skb_hit);
rc |= unregister_trace_napi_poll(trace_napi_poll_hit);
tracepoint_synchronize_unregister();
/*
* Clean the device list
*/
list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) {
if (new_stat->dev == NULL) {
list_del_rcu(&new_stat->list);
call_rcu(&new_stat->rcu, free_dm_hw_stat);
}
}
break;
default:
rc = 1;
break;
}
if (!rc)
trace_state = state;
spin_unlock(&trace_state_lock);
if (rc)
return -EINPROGRESS;
return rc;
@ -204,6 +271,44 @@ static int net_dm_cmd_trace(struct sk_buff *skb,
return -ENOTSUPP;
}
static int dropmon_net_event(struct notifier_block *ev_block,
unsigned long event, void *ptr)
{
struct net_device *dev = ptr;
struct dm_hw_stat_delta *new_stat = NULL;
struct dm_hw_stat_delta *tmp;
switch (event) {
case NETDEV_REGISTER:
new_stat = kzalloc(sizeof(struct dm_hw_stat_delta), GFP_KERNEL);
if (!new_stat)
goto out;
new_stat->dev = dev;
INIT_RCU_HEAD(&new_stat->rcu);
spin_lock(&trace_state_lock);
list_add_rcu(&new_stat->list, &hw_stats_list);
spin_unlock(&trace_state_lock);
break;
case NETDEV_UNREGISTER:
spin_lock(&trace_state_lock);
list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) {
if (new_stat->dev == dev) {
new_stat->dev = NULL;
if (trace_state == TRACE_OFF) {
list_del_rcu(&new_stat->list);
call_rcu(&new_stat->rcu, free_dm_hw_stat);
break;
}
}
}
spin_unlock(&trace_state_lock);
break;
}
out:
return NOTIFY_DONE;
}
static struct genl_ops dropmon_ops[] = {
{
@ -220,6 +325,10 @@ static struct genl_ops dropmon_ops[] = {
},
};
static struct notifier_block dropmon_net_notifier = {
.notifier_call = dropmon_net_event
};
static int __init init_net_drop_monitor(void)
{
int cpu;
@ -243,12 +352,18 @@ static int __init init_net_drop_monitor(void)
ret = genl_register_ops(&net_drop_monitor_family,
&dropmon_ops[i]);
if (ret) {
printk(KERN_CRIT "failed to register operation %d\n",
printk(KERN_CRIT "Failed to register operation %d\n",
dropmon_ops[i].cmd);
goto out_unreg;
}
}
rc = register_netdevice_notifier(&dropmon_net_notifier);
if (rc < 0) {
printk(KERN_CRIT "Failed to register netdevice notifier\n");
goto out_unreg;
}
rc = 0;
for_each_present_cpu(cpu) {
@ -259,6 +374,7 @@ static int __init init_net_drop_monitor(void)
data->send_timer.data = cpu;
data->send_timer.function = sched_send_work;
}
goto out;
out_unreg:

4
net/core/net-traces.c
View File

@ -20,6 +20,7 @@
#include <linux/netlink.h>
#include <linux/net_dropmon.h>
#include <trace/skb.h>
#include <trace/napi.h>
#include <asm/unaligned.h>
#include <asm/bitops.h>
@ -27,3 +28,6 @@
DEFINE_TRACE(kfree_skb);
EXPORT_TRACEPOINT_SYMBOL_GPL(kfree_skb);
DEFINE_TRACE(napi_poll);
EXPORT_TRACEPOINT_SYMBOL_GPL(napi_poll);

2
net/core/netpoll.c
View File

@ -24,6 +24,7 @@
#include <net/tcp.h>
#include <net/udp.h>
#include <asm/unaligned.h>
#include <trace/napi.h>
/*
* We maintain a small pool of fully-sized skbs, to make sure the
@ -137,6 +138,7 @@ static int poll_one_napi(struct netpoll_info *npinfo,
set_bit(NAPI_STATE_NPSVC, &napi->state);
work = napi->poll(napi, budget);
trace_napi_poll(napi->dev);
clear_bit(NAPI_STATE_NPSVC, &napi->state);
atomic_dec(&trapped);