net: Temporarily backout SKB sources tracer.

Steven Rostedt has suggested that Neil work with the tracing
folks, trying to use TRACE_EVENT as the mechanism for
implementation.  And if that doesn't workout we can investigate
other solutions such as that one which was tried here.

This reverts the following 2 commits:

5a165657bef7c47e5ff4cd138f7758ef6278e87b
("net: skb ftracer - Add config option to enable new ftracer (v3)")

9ec04da7489d2c9ae01ea6e9b5fa313ccf3d35fb
("net: skb ftracer - Add actual ftrace code to kernel (v3)")

Signed-off-by: David S. Miller <davem@davemloft.net>

kernel/trace/Kconfig

@@ -234,17 +234,6 @@ config BOOT_TRACER
 	  You must pass in initcall_debug and ftrace=initcall to the kernel
 	  command line to enable this on bootup.
 
-config SKB_SOURCES_TRACER
-	bool "Trace skb source information"
-	depends on NET
-	select GENERIC_TRACER
-	help
-	   This tracer helps developers/sysadmins correlate skb allocation and
-	   consumption.  The idea being that some processes will primarily consume data
-	   that was allocated on certain numa nodes.  By being able to visualize which
-	   nodes the data was allocated on, a sysadmin or developer can optimize the
-	   scheduling of those processes to cut back on cross node chatter.
-
 config TRACE_BRANCH_PROFILING
 	bool
 	select GENERIC_TRACER

kernel/trace/Makefile

@@ -49,7 +49,6 @@ 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

kernel/trace/trace.h

@@ -11,7 +11,6 @@
 #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>
@@ -41,7 +40,6 @@ enum trace_type {
 	TRACE_KMEM_FREE,
 	TRACE_POWER,
 	TRACE_BLK,
-	TRACE_SKB_SOURCE,
 
 	__TRACE_LAST_TYPE,
 };
@@ -173,21 +171,6 @@ 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_*(). */
@@ -340,8 +323,6 @@ 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)
 

kernel/trace/trace_skb_sources.c

@@ -1,154 +0,0 @@
-/*
- * 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);