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authorNeil Horman <nhorman@tuxdriver.com>2009-05-21 07:36:08 +0000
committerDavid S. Miller <davem@davemloft.net>2009-05-21 16:50:21 -0700
commit4ea7e38696c7e798c47ebbecadfd392f23f814f9 (patch)
tree1e144d0c79fb667860ff7fa0ed203984e888ddab
parentd95ed9275edcb8995bda31005bb3f55e087626d7 (diff)
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: 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>
-rw-r--r--include/linux/net_dropmon.h8
-rw-r--r--include/trace/napi.h11
-rw-r--r--net/core/dev.c5
-rw-r--r--net/core/drop_monitor.c124
-rw-r--r--net/core/net-traces.c4
-rw-r--r--net/core/netpoll.c2
6 files changed, 149 insertions, 5 deletions
diff --git a/include/linux/net_dropmon.h b/include/linux/net_dropmon.h
index 0217fb81a630..e8a8b5c50ed0 100644
--- a/include/linux/net_dropmon.h
+++ b/include/linux/net_dropmon.h
@@ -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
diff --git a/include/trace/napi.h b/include/trace/napi.h
new file mode 100644
index 000000000000..a8989c4547e7
--- /dev/null
+++ b/include/trace/napi.h
@@ -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
diff --git a/net/core/dev.c b/net/core/dev.c
index 92ebeca29901..3942266d1f6c 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -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);
diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index 2797b711a978..a6c2ac2828fb 100644
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -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:
diff --git a/net/core/net-traces.c b/net/core/net-traces.c
index c8fb45665e4f..b07b25bd2cde 100644
--- a/net/core/net-traces.c
+++ b/net/core/net-traces.c
@@ -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);
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 64f51eec6576..00b14e2c50ed 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -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);