[3/3] net: Add ftracer to help optimize process scheduling based on incomming frame allocations (v2)

diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 844164d..ee5e5b1 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -49,6 +49,7 @@  obj-$(CONFIG_BLK_DEV_IO_TRACE) += blktrace.o
 ifeq ($(CONFIG_BLOCK),y)
 obj-$(CONFIG_EVENT_TRACING) += blktrace.o
 endif
+obj-$(CONFIG_SKB_SOURCES_TRACER) += trace_skb_sources.o
 obj-$(CONFIG_EVENT_TRACING) += trace_events.o
 obj-$(CONFIG_EVENT_TRACING) += trace_export.o
 obj-$(CONFIG_FTRACE_SYSCALLS) += trace_syscalls.o
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 3548ae5..8c1d458 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -11,6 +11,7 @@ 
 #include <trace/boot.h>
 #include <linux/kmemtrace.h>
 #include <trace/power.h>
+#include <trace/events/skb.h>
 
 #include <linux/trace_seq.h>
 #include <linux/ftrace_event.h>
@@ -40,6 +41,7 @@  enum trace_type {
 	TRACE_KMEM_FREE,
 	TRACE_POWER,
 	TRACE_BLK,
+	TRACE_SKB_SOURCE,
 
 	__TRACE_LAST_TYPE,
 };
@@ -171,6 +173,21 @@  struct trace_power {
 	struct power_trace	state_data;
 };
 
+struct skb_record {
+	pid_t pid;		/* pid of the copying process */
+	int anid;		/* node where skb was allocated */
+	int cnid;		/* node to which skb was copied in userspace */
+	char ifname[IFNAMSIZ];	/* Name of the receiving interface */
+	int rx_queue;		/* The rx queue the skb was received on */
+	int ccpu;		/* Cpu the application got this frame from */
+	int len;		/* length of the data copied */
+};
+
+struct trace_skb_event {
+	struct trace_entry	ent;
+	struct skb_record	event_data;
+};
+
 enum kmemtrace_type_id {
 	KMEMTRACE_TYPE_KMALLOC = 0,	/* kmalloc() or kfree(). */
 	KMEMTRACE_TYPE_CACHE,		/* kmem_cache_*(). */
@@ -323,6 +340,8 @@  extern void __ftrace_bad_type(void);
 			  TRACE_SYSCALL_ENTER);				\
 		IF_ASSIGN(var, ent, struct syscall_trace_exit,		\
 			  TRACE_SYSCALL_EXIT);				\
+		IF_ASSIGN(var, ent, struct trace_skb_event,		\
+			  TRACE_SKB_SOURCE);				\
 		__ftrace_bad_type();					\
 	} while (0)
 
diff --git a/kernel/trace/trace_skb_sources.c b/kernel/trace/trace_skb_sources.c
new file mode 100644
index 0000000..4ba3671
--- /dev/null
+++ b/kernel/trace/trace_skb_sources.c
@@ -0,0 +1,154 @@ 
+/*
+ * ring buffer based tracer for analyzing per-socket skb sources
+ *
+ * Neil Horman <nhorman@tuxdriver.com> 
+ * Copyright (C) 2009
+ *
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/debugfs.h>
+#include <trace/events/skb.h>
+#include <linux/kallsyms.h>
+#include <linux/module.h>
+#include <linux/hardirq.h>
+#include <linux/netdevice.h>
+#include <net/sock.h>
+
+#include "trace.h"
+#include "trace_output.h"
+
+EXPORT_TRACEPOINT_SYMBOL_GPL(skb_copy_datagram_iovec);
+
+static struct trace_array *skb_trace;
+static int __read_mostly trace_skb_source_enabled;
+
+static void probe_skb_dequeue(const struct sk_buff *skb, int len)
+{
+	struct ring_buffer_event *event;
+	struct trace_skb_event *entry;
+	struct trace_array *tr = skb_trace;
+	struct net_device *dev;
+
+	if (!trace_skb_source_enabled)
+		return;
+
+	if (in_interrupt())
+		return;
+
+	event = trace_buffer_lock_reserve(tr, TRACE_SKB_SOURCE,
+					  sizeof(*entry), 0, 0);
+	if (!event)
+		return;
+	entry = ring_buffer_event_data(event);
+
+	entry->event_data.pid = current->pid;
+	entry->event_data.anid = page_to_nid(virt_to_page(skb->data));
+	entry->event_data.cnid = cpu_to_node(smp_processor_id());
+	entry->event_data.len = len;
+	entry->event_data.rx_queue = skb->queue_mapping;
+	entry->event_data.ccpu = smp_processor_id();
+
+	dev = dev_get_by_index(sock_net(skb->sk), skb->iif);
+	if (dev) {
+		memcpy(entry->event_data.ifname, dev->name, IFNAMSIZ);
+		dev_put(dev);
+	} else {
+		strcpy(entry->event_data.ifname, "Unknown");
+	}
+
+	trace_buffer_unlock_commit(tr, event, 0, 0);
+}
+
+static int tracing_skb_source_register(void)
+{
+	int ret;
+
+	ret = register_trace_skb_copy_datagram_iovec(probe_skb_dequeue);
+	if (ret)
+		pr_info("skb source trace: Couldn't activate dequeue tracepoint");
+	
+	return ret;
+}
+
+static void start_skb_source_trace(struct trace_array *tr)
+{
+	trace_skb_source_enabled = 1;
+}
+
+static void stop_skb_source_trace(struct trace_array *tr)
+{
+	trace_skb_source_enabled = 0;
+}
+
+static void skb_source_trace_reset(struct trace_array *tr)
+{
+	trace_skb_source_enabled = 0;
+	unregister_trace_skb_copy_datagram_iovec(probe_skb_dequeue);
+}
+
+
+static int skb_source_trace_init(struct trace_array *tr)
+{
+	int cpu;
+	skb_trace = tr;
+
+	trace_skb_source_enabled = 1;
+	tracing_skb_source_register();
+
+	for_each_cpu(cpu, cpu_possible_mask)
+		tracing_reset(tr, cpu);
+	return 0;
+}
+
+static enum print_line_t skb_source_print_line(struct trace_iterator *iter)
+{
+	int ret = 0;
+	struct trace_entry *entry = iter->ent;
+	struct trace_skb_event *event;
+	struct skb_record *record;
+	struct trace_seq *s = &iter->seq;
+
+	trace_assign_type(event, entry);
+	record = &event->event_data;
+	if (entry->type != TRACE_SKB_SOURCE)
+		return TRACE_TYPE_UNHANDLED;
+
+	ret = trace_seq_printf(s, "	%d	%d	%d	%s	%d	%d	%d\n",
+			record->pid,
+			record->anid,
+			record->cnid,
+			record->ifname,
+			record->rx_queue,
+			record->ccpu,
+			record->len);
+
+	if (!ret)
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	return TRACE_TYPE_HANDLED;
+}
+
+static void skb_source_print_header(struct seq_file *s)
+{
+	seq_puts(s, "#	PID	ANID	CNID	IFC	RXQ	CCPU	LEN\n");
+	seq_puts(s, "#	 |	 |	 |	 |	 |	 |	 |\n");
+}
+
+static struct tracer skb_source_tracer __read_mostly =
+{
+	.name		= "skb_sources",
+	.init		= skb_source_trace_init,
+	.start		= start_skb_source_trace,
+	.stop		= stop_skb_source_trace,
+	.reset		= skb_source_trace_reset,
+	.print_line	= skb_source_print_line,
+	.print_header	= skb_source_print_header,
+};
+
+static int init_skb_source_trace(void)
+{
+	return register_tracer(&skb_source_tracer);
+}
+device_initcall(init_skb_source_trace);