Commit 4ea7e386 authored by Neil Horman's avatar Neil Horman Committed by David S. Miller

dropmon: add ability to detect when hardware dropsrxpackets

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: default avatarNeil 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: default avatarDavid S. Miller <davem@davemloft.net>
parent d95ed927
...@@ -2,12 +2,20 @@ ...@@ -2,12 +2,20 @@
#define __NET_DROPMON_H #define __NET_DROPMON_H
#include <linux/netlink.h> #include <linux/netlink.h>
#include <linux/types.h>
struct net_dm_drop_point { struct net_dm_drop_point {
__u8 pc[8]; __u8 pc[8];
__u32 count; __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_VERSION 0
#define NET_DM_CFG_ALERT_COUNT 1 #define NET_DM_CFG_ALERT_COUNT 1
#define NET_DM_CFG_ALERT_DELAY 2 #define NET_DM_CFG_ALERT_DELAY 2
......
#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
...@@ -126,6 +126,7 @@ ...@@ -126,6 +126,7 @@
#include <linux/in.h> #include <linux/in.h>
#include <linux/jhash.h> #include <linux/jhash.h>
#include <linux/random.h> #include <linux/random.h>
#include <trace/napi.h>
#include "net-sysfs.h" #include "net-sysfs.h"
...@@ -2771,8 +2772,10 @@ static void net_rx_action(struct softirq_action *h) ...@@ -2771,8 +2772,10 @@ static void net_rx_action(struct softirq_action *h)
* accidently calling ->poll() when NAPI is not scheduled. * accidently calling ->poll() when NAPI is not scheduled.
*/ */
work = 0; work = 0;
if (test_bit(NAPI_STATE_SCHED, &n->state)) if (test_bit(NAPI_STATE_SCHED, &n->state)) {
work = n->poll(n, weight); work = n->poll(n, weight);
trace_napi_poll(n);
}
WARN_ON_ONCE(work > weight); WARN_ON_ONCE(work > weight);
......
...@@ -22,8 +22,10 @@ ...@@ -22,8 +22,10 @@
#include <linux/timer.h> #include <linux/timer.h>
#include <linux/bitops.h> #include <linux/bitops.h>
#include <net/genetlink.h> #include <net/genetlink.h>
#include <net/netevent.h>
#include <trace/skb.h> #include <trace/skb.h>
#include <trace/napi.h>
#include <asm/unaligned.h> #include <asm/unaligned.h>
...@@ -38,7 +40,8 @@ static void send_dm_alert(struct work_struct *unused); ...@@ -38,7 +40,8 @@ static void send_dm_alert(struct work_struct *unused);
* and the work handle that will send up * and the work handle that will send up
* netlink alerts * 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 per_cpu_dm_data {
struct work_struct dm_alert_work; struct work_struct dm_alert_work;
...@@ -47,6 +50,13 @@ struct per_cpu_dm_data { ...@@ -47,6 +50,13 @@ struct per_cpu_dm_data {
struct timer_list send_timer; 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 = { static struct genl_family net_drop_monitor_family = {
.id = GENL_ID_GENERATE, .id = GENL_ID_GENERATE,
.hdrsize = 0, .hdrsize = 0,
...@@ -59,7 +69,8 @@ static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data); ...@@ -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_hit_limit = 64;
static int dm_delay = 1; 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) static void reset_per_cpu_data(struct per_cpu_dm_data *data)
{ {
...@@ -115,7 +126,7 @@ static void sched_send_work(unsigned long unused) ...@@ -115,7 +126,7 @@ static void sched_send_work(unsigned long unused)
schedule_work(&data->dm_alert_work); 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 net_dm_alert_msg *msg;
struct nlmsghdr *nlh; struct nlmsghdr *nlh;
...@@ -159,24 +170,80 @@ static void trace_kfree_skb_hit(struct sk_buff *skb, void *location) ...@@ -159,24 +170,80 @@ static void trace_kfree_skb_hit(struct sk_buff *skb, void *location)
return; 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) static int set_all_monitor_traces(int state)
{ {
int rc = 0; int rc = 0;
struct dm_hw_stat_delta *new_stat = NULL;
struct dm_hw_stat_delta *temp;
spin_lock(&trace_state_lock);
switch (state) { switch (state) {
case TRACE_ON: case TRACE_ON:
rc |= register_trace_kfree_skb(trace_kfree_skb_hit); rc |= register_trace_kfree_skb(trace_kfree_skb_hit);
rc |= register_trace_napi_poll(trace_napi_poll_hit);
break; break;
case TRACE_OFF: case TRACE_OFF:
rc |= unregister_trace_kfree_skb(trace_kfree_skb_hit); rc |= unregister_trace_kfree_skb(trace_kfree_skb_hit);
rc |= unregister_trace_napi_poll(trace_napi_poll_hit);
tracepoint_synchronize_unregister(); 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; break;
default: default:
rc = 1; rc = 1;
break; break;
} }
if (!rc)
trace_state = state;
spin_unlock(&trace_state_lock);
if (rc) if (rc)
return -EINPROGRESS; return -EINPROGRESS;
return rc; return rc;
...@@ -204,6 +271,44 @@ static int net_dm_cmd_trace(struct sk_buff *skb, ...@@ -204,6 +271,44 @@ static int net_dm_cmd_trace(struct sk_buff *skb,
return -ENOTSUPP; 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[] = { static struct genl_ops dropmon_ops[] = {
{ {
...@@ -220,6 +325,10 @@ 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) static int __init init_net_drop_monitor(void)
{ {
int cpu; int cpu;
...@@ -243,12 +352,18 @@ static int __init init_net_drop_monitor(void) ...@@ -243,12 +352,18 @@ static int __init init_net_drop_monitor(void)
ret = genl_register_ops(&net_drop_monitor_family, ret = genl_register_ops(&net_drop_monitor_family,
&dropmon_ops[i]); &dropmon_ops[i]);
if (ret) { if (ret) {
printk(KERN_CRIT "failed to register operation %d\n", printk(KERN_CRIT "Failed to register operation %d\n",
dropmon_ops[i].cmd); dropmon_ops[i].cmd);
goto out_unreg; 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; rc = 0;
for_each_present_cpu(cpu) { for_each_present_cpu(cpu) {
...@@ -259,6 +374,7 @@ static int __init init_net_drop_monitor(void) ...@@ -259,6 +374,7 @@ static int __init init_net_drop_monitor(void)
data->send_timer.data = cpu; data->send_timer.data = cpu;
data->send_timer.function = sched_send_work; data->send_timer.function = sched_send_work;
} }
goto out; goto out;
out_unreg: out_unreg:
......
...@@ -20,6 +20,7 @@ ...@@ -20,6 +20,7 @@
#include <linux/netlink.h> #include <linux/netlink.h>
#include <linux/net_dropmon.h> #include <linux/net_dropmon.h>
#include <trace/skb.h> #include <trace/skb.h>
#include <trace/napi.h>
#include <asm/unaligned.h> #include <asm/unaligned.h>
#include <asm/bitops.h> #include <asm/bitops.h>
...@@ -27,3 +28,6 @@ ...@@ -27,3 +28,6 @@
DEFINE_TRACE(kfree_skb); DEFINE_TRACE(kfree_skb);
EXPORT_TRACEPOINT_SYMBOL_GPL(kfree_skb); EXPORT_TRACEPOINT_SYMBOL_GPL(kfree_skb);
DEFINE_TRACE(napi_poll);
EXPORT_TRACEPOINT_SYMBOL_GPL(napi_poll);
...@@ -24,6 +24,7 @@ ...@@ -24,6 +24,7 @@
#include <net/tcp.h> #include <net/tcp.h>
#include <net/udp.h> #include <net/udp.h>
#include <asm/unaligned.h> #include <asm/unaligned.h>
#include <trace/napi.h>
/* /*
* We maintain a small pool of fully-sized skbs, to make sure the * 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, ...@@ -137,6 +138,7 @@ static int poll_one_napi(struct netpoll_info *npinfo,
set_bit(NAPI_STATE_NPSVC, &napi->state); set_bit(NAPI_STATE_NPSVC, &napi->state);
work = napi->poll(napi, budget); work = napi->poll(napi, budget);
trace_napi_poll(napi->dev);
clear_bit(NAPI_STATE_NPSVC, &napi->state); clear_bit(NAPI_STATE_NPSVC, &napi->state);
atomic_dec(&trapped); atomic_dec(&trapped);
......
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