Merge branch 'tracing/core-v2' into tracing-for-linus

Conflicts:
	include/linux/slub_def.h
	lib/Kconfig.debug
	mm/slob.c
	mm/slub.c

50 files changed, 11325 insertions, 2529 deletions

diff --git a/kernel/extable.c b/kernel/extable.c
index e136ed8d82b..b54a6017b6b 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -15,11 +15,22 @@
     along with this program; if not, write to the Free Software
     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
+#include <linux/ftrace.h>
+#include <linux/memory.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/init.h>
-#include <linux/ftrace.h>
-#include <asm/uaccess.h>
+
 #include <asm/sections.h>
+#include <asm/uaccess.h>
+
+/*
+ * mutex protecting text section modification (dynamic code patching).
+ * some users need to sleep (allocating memory...) while they hold this lock.
+ *
+ * NOT exported to modules - patching kernel text is a really delicate matter.
+ */
+DEFINE_MUTEX(text_mutex);
 
 extern struct exception_table_entry __start___ex_table[];
 extern struct exception_table_entry __stop___ex_table[];
@@ -41,7 +52,7 @@ const struct exception_table_entry *search_exception_tables(unsigned long addr)
 	return e;
 }
 
-__notrace_funcgraph int core_kernel_text(unsigned long addr)
+int core_kernel_text(unsigned long addr)
 {
 	if (addr >= (unsigned long)_stext &&
 	    addr <= (unsigned long)_etext)
@@ -54,7 +65,7 @@ __notrace_funcgraph int core_kernel_text(unsigned long addr)
 	return 0;
 }
 
-__notrace_funcgraph int __kernel_text_address(unsigned long addr)
+int __kernel_text_address(unsigned long addr)
 {
 	if (core_kernel_text(addr))
 		return 1;
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 9ebf7796887..343acecae62 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -17,6 +17,7 @@
 #include <linux/kernel_stat.h>
 #include <linux/rculist.h>
 #include <linux/hash.h>
+#include <trace/irq.h>
 #include <linux/bootmem.h>
 
 #include "internals.h"
@@ -338,6 +339,9 @@ irqreturn_t no_action(int cpl, void *dev_id)
 	return IRQ_NONE;
 }
 
+DEFINE_TRACE(irq_handler_entry);
+DEFINE_TRACE(irq_handler_exit);
+
 /**
  * handle_IRQ_event - irq action chain handler
  * @irq:	the interrupt number
@@ -356,7 +360,9 @@ irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 		local_irq_enable_in_hardirq();
 
 	do {
+		trace_irq_handler_entry(irq, action);
 		ret = action->handler(irq, action->dev_id);
+		trace_irq_handler_exit(irq, action, ret);
 		if (ret == IRQ_HANDLED)
 			status |= action->flags;
 		retval |= ret;
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 7ba8cd9845c..5016bfb682b 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -43,6 +43,7 @@
 #include <linux/seq_file.h>
 #include <linux/debugfs.h>
 #include <linux/kdebug.h>
+#include <linux/memory.h>
 
 #include <asm-generic/sections.h>
 #include <asm/cacheflush.h>
@@ -699,9 +700,10 @@ int __kprobes register_kprobe(struct kprobe *p)
 		goto out;
 	}
 
+	mutex_lock(&text_mutex);
 	ret = arch_prepare_kprobe(p);
 	if (ret)
-		goto out;
+		goto out_unlock_text;
 
 	INIT_HLIST_NODE(&p->hlist);
 	hlist_add_head_rcu(&p->hlist,
@@ -710,6 +712,8 @@ int __kprobes register_kprobe(struct kprobe *p)
 	if (kprobe_enabled)
 		arch_arm_kprobe(p);
 
+out_unlock_text:
+	mutex_unlock(&text_mutex);
 out:
 	mutex_unlock(&kprobe_mutex);
 
@@ -746,8 +750,11 @@ valid_p:
 		 * enabled and not gone - otherwise, the breakpoint would
 		 * already have been removed. We save on flushing icache.
 		 */
-		if (kprobe_enabled && !kprobe_gone(old_p))
+		if (kprobe_enabled && !kprobe_gone(old_p)) {
+			mutex_lock(&text_mutex);
 			arch_disarm_kprobe(p);
+			mutex_unlock(&text_mutex);
+		}
 		hlist_del_rcu(&old_p->hlist);
 	} else {
 		if (p->break_handler && !kprobe_gone(p))
@@ -912,10 +919,8 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p,
 		ri->rp = rp;
 		ri->task = current;
 
-		if (rp->entry_handler && rp->entry_handler(ri, regs)) {
-			spin_unlock_irqrestore(&rp->lock, flags);
+		if (rp->entry_handler && rp->entry_handler(ri, regs))
 			return 0;
-		}
 
 		arch_prepare_kretprobe(ri, regs);
 
@@ -1280,12 +1285,14 @@ static void __kprobes enable_all_kprobes(void)
 	if (kprobe_enabled)
 		goto already_enabled;
 
+	mutex_lock(&text_mutex);
 	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
 		head = &kprobe_table[i];
 		hlist_for_each_entry_rcu(p, node, head, hlist)
 			if (!kprobe_gone(p))
 				arch_arm_kprobe(p);
 	}
+	mutex_unlock(&text_mutex);
 
 	kprobe_enabled = true;
 	printk(KERN_INFO "Kprobes globally enabled\n");
@@ -1310,6 +1317,7 @@ static void __kprobes disable_all_kprobes(void)
 
 	kprobe_enabled = false;
 	printk(KERN_INFO "Kprobes globally disabled\n");
+	mutex_lock(&text_mutex);
 	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
 		head = &kprobe_table[i];
 		hlist_for_each_entry_rcu(p, node, head, hlist) {
@@ -1318,6 +1326,7 @@ static void __kprobes disable_all_kprobes(void)
 		}
 	}
 
+	mutex_unlock(&text_mutex);
 	mutex_unlock(&kprobe_mutex);
 	/* Allow all currently running kprobes to complete */
 	synchronize_sched();
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 3673a3f44d9..81b5f33970b 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -42,6 +42,7 @@
 #include <linux/hash.h>
 #include <linux/ftrace.h>
 #include <linux/stringify.h>
+#include <trace/lockdep.h>
 
 #include <asm/sections.h>
 
@@ -433,13 +434,6 @@ atomic_t nr_find_usage_forwards_checks;
 atomic_t nr_find_usage_forwards_recursions;
 atomic_t nr_find_usage_backwards_checks;
 atomic_t nr_find_usage_backwards_recursions;
-# define debug_atomic_inc(ptr)		atomic_inc(ptr)
-# define debug_atomic_dec(ptr)		atomic_dec(ptr)
-# define debug_atomic_read(ptr)		atomic_read(ptr)
-#else
-# define debug_atomic_inc(ptr)		do { } while (0)
-# define debug_atomic_dec(ptr)		do { } while (0)
-# define debug_atomic_read(ptr)		0
 #endif
 
 /*
@@ -1900,9 +1894,9 @@ print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other,
 		curr->comm, task_pid_nr(curr));
 	print_lock(this);
 	if (forwards)
-		printk("but this lock took another, %s-irq-unsafe lock in the past:\n", irqclass);
+		printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass);
 	else
-		printk("but this lock was taken by another, %s-irq-safe lock in the past:\n", irqclass);
+		printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass);
 	print_lock_name(other);
 	printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");
 
@@ -2015,7 +2009,8 @@ typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
 			     enum lock_usage_bit bit, const char *name);
 
 static int
-mark_lock_irq(struct task_struct *curr, struct held_lock *this, int new_bit)
+mark_lock_irq(struct task_struct *curr, struct held_lock *this,
+		enum lock_usage_bit new_bit)
 {
 	int excl_bit = exclusive_bit(new_bit);
 	int read = new_bit & 1;
@@ -2043,7 +2038,7 @@ mark_lock_irq(struct task_struct *curr, struct held_lock *this, int new_bit)
 	 * states.
 	 */
 	if ((!read || !dir || STRICT_READ_CHECKS) &&
-			!usage(curr, this, excl_bit, state_name(new_bit)))
+			!usage(curr, this, excl_bit, state_name(new_bit & ~1)))
 		return 0;
 
 	/*
@@ -2929,6 +2924,8 @@ void lock_set_class(struct lockdep_map *lock, const char *name,
 }
 EXPORT_SYMBOL_GPL(lock_set_class);
 
+DEFINE_TRACE(lock_acquire);
+
 /*
  * We are not always called with irqs disabled - do that here,
  * and also avoid lockdep recursion:
@@ -2939,6 +2936,8 @@ void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 {
 	unsigned long flags;
 
+	trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);
+
 	if (unlikely(current->lockdep_recursion))
 		return;
 
@@ -2953,11 +2952,15 @@ void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
 }
 EXPORT_SYMBOL_GPL(lock_acquire);
 
+DEFINE_TRACE(lock_release);
+
 void lock_release(struct lockdep_map *lock, int nested,
 			  unsigned long ip)
 {
 	unsigned long flags;
 
+	trace_lock_release(lock, nested, ip);
+
 	if (unlikely(current->lockdep_recursion))
 		return;
 
@@ -3106,10 +3109,14 @@ found_it:
 	lock->ip = ip;
 }
 
+DEFINE_TRACE(lock_contended);
+
 void lock_contended(struct lockdep_map *lock, unsigned long ip)
 {
 	unsigned long flags;
 
+	trace_lock_contended(lock, ip);
+
 	if (unlikely(!lock_stat))
 		return;
 
@@ -3125,10 +3132,14 @@ void lock_contended(struct lockdep_map *lock, unsigned long ip)
 }
 EXPORT_SYMBOL_GPL(lock_contended);
 
+DEFINE_TRACE(lock_acquired);
+
 void lock_acquired(struct lockdep_map *lock, unsigned long ip)
 {
 	unsigned long flags;
 
+	trace_lock_acquired(lock, ip);
+
 	if (unlikely(!lock_stat))
 		return;
 
diff --git a/kernel/module.c b/kernel/module.c
index f77ac320d0b..41f50605eed 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2766,7 +2766,7 @@ int is_module_address(unsigned long addr)
 
 
 /* Is this a valid kernel address? */
-__notrace_funcgraph struct module *__module_text_address(unsigned long addr)
+struct module *__module_text_address(unsigned long addr)
 {
 	struct module *mod;
 
diff --git a/kernel/relay.c b/kernel/relay.c
index 8f2179c8056..824b91ac10f 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -677,9 +677,7 @@ int relay_late_setup_files(struct rchan *chan,
 	 */
 	for_each_online_cpu(i) {
 		if (unlikely(!chan->buf[i])) {
-			printk(KERN_ERR "relay_late_setup_files: CPU %u "
-					"has no buffer, it must have!\n", i);
-			BUG();
+			WARN_ONCE(1, KERN_ERR "CPU has no buffer!\n");
 			err = -EINVAL;
 			break;
 		}
diff --git a/kernel/sched.c b/kernel/sched.c
index 73513f4e19d..f01cb63d135 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4781,10 +4781,7 @@ void scheduler_tick(void)
 #endif
 }
 
-#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
-				defined(CONFIG_PREEMPT_TRACER))
-
-static inline unsigned long get_parent_ip(unsigned long addr)
+unsigned long get_parent_ip(unsigned long addr)
 {
 	if (in_lock_functions(addr)) {
 		addr = CALLER_ADDR2;
@@ -4794,6 +4791,9 @@ static inline unsigned long get_parent_ip(unsigned long addr)
 	return addr;
 }
 
+#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
+				defined(CONFIG_PREEMPT_TRACER))
+
 void __kprobes add_preempt_count(int val)
 {
 #ifdef CONFIG_DEBUG_PREEMPT
diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c
index 390f33234bd..819f17ac796 100644
--- a/kernel/sched_clock.c
+++ b/kernel/sched_clock.c
@@ -25,6 +25,7 @@
  * consistent between cpus (never more than 2 jiffies difference).
  */
 #include <linux/spinlock.h>
+#include <linux/hardirq.h>
 #include <linux/module.h>
 #include <linux/percpu.h>
 #include <linux/ktime.h>
@@ -154,6 +155,17 @@ u64 sched_clock_cpu(int cpu)
 		return sched_clock();
 
 	scd = cpu_sdc(cpu);
+
+	/*
+	 * Normally this is not called in NMI context - but if it is,
+	 * trying to do any locking here is totally lethal.
+	 */
+	if (unlikely(in_nmi()))
+		return scd->clock;
+
+	if (unlikely(!sched_clock_running))
+		return 0ull;
+
 	WARN_ON_ONCE(!irqs_disabled());
 	now = sched_clock();
 
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 57d3f67f6f3..65ff3e3961b 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -21,8 +21,10 @@
 #include <linux/freezer.h>
 #include <linux/kthread.h>
 #include <linux/rcupdate.h>
+#include <linux/ftrace.h>
 #include <linux/smp.h>
 #include <linux/tick.h>
+#include <trace/irq.h>
 
 #include <asm/irq.h>
 /*
@@ -52,6 +54,11 @@ static struct softirq_action softirq_vec[NR_SOFTIRQS] __cacheline_aligned_in_smp
 
 static DEFINE_PER_CPU(struct task_struct *, ksoftirqd);
 
+char *softirq_to_name[NR_SOFTIRQS] = {
+	"HI", "TIMER", "NET_TX", "NET_RX", "BLOCK",
+	"TASKLET", "SCHED", "HRTIMER",	"RCU"
+};
+
 /*
  * we cannot loop indefinitely here to avoid userspace starvation,
  * but we also don't want to introduce a worst case 1/HZ latency
@@ -79,13 +86,23 @@ static void __local_bh_disable(unsigned long ip)
 	WARN_ON_ONCE(in_irq());
 
 	raw_local_irq_save(flags);
-	add_preempt_count(SOFTIRQ_OFFSET);
+	/*
+	 * The preempt tracer hooks into add_preempt_count and will break
+	 * lockdep because it calls back into lockdep after SOFTIRQ_OFFSET
+	 * is set and before current->softirq_enabled is cleared.
+	 * We must manually increment preempt_count here and manually
+	 * call the trace_preempt_off later.
+	 */
+	preempt_count() += SOFTIRQ_OFFSET;
 	/*
 	 * Were softirqs turned off above:
 	 */
 	if (softirq_count() == SOFTIRQ_OFFSET)
 		trace_softirqs_off(ip);
 	raw_local_irq_restore(flags);
+
+	if (preempt_count() == SOFTIRQ_OFFSET)
+		trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
 }
 #else /* !CONFIG_TRACE_IRQFLAGS */
 static inline void __local_bh_disable(unsigned long ip)
@@ -169,6 +186,9 @@ EXPORT_SYMBOL(local_bh_enable_ip);
  */
 #define MAX_SOFTIRQ_RESTART 10
 
+DEFINE_TRACE(softirq_entry);
+DEFINE_TRACE(softirq_exit);
+
 asmlinkage void __do_softirq(void)
 {
 	struct softirq_action *h;
@@ -180,7 +200,7 @@ asmlinkage void __do_softirq(void)
 	account_system_vtime(current);
 
 	__local_bh_disable((unsigned long)__builtin_return_address(0));
-	trace_softirq_enter();
+	lockdep_softirq_enter();
 
 	cpu = smp_processor_id();
 restart:
@@ -195,12 +215,14 @@ restart:
 		if (pending & 1) {
 			int prev_count = preempt_count();
 
+			trace_softirq_entry(h, softirq_vec);
 			h->action(h);
-
+			trace_softirq_exit(h, softirq_vec);
 			if (unlikely(prev_count != preempt_count())) {
-				printk(KERN_ERR "huh, entered softirq %td %p"
+				printk(KERN_ERR "huh, entered softirq %td %s %p"
 				       "with preempt_count %08x,"
 				       " exited with %08x?\n", h - softirq_vec,
+				       softirq_to_name[h - softirq_vec],
 				       h->action, prev_count, preempt_count());
 				preempt_count() = prev_count;
 			}
@@ -220,7 +242,7 @@ restart:
 	if (pending)
 		wakeup_softirqd();
 
-	trace_softirq_exit();
+	lockdep_softirq_exit();
 
 	account_system_vtime(current);
 	_local_bh_enable();
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 34e707e5ab8..8a4d7293104 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -9,6 +9,9 @@ config USER_STACKTRACE_SUPPORT
 config NOP_TRACER
 	bool
 
+config HAVE_FTRACE_NMI_ENTER
+	bool
+
 config HAVE_FUNCTION_TRACER
 	bool
 
@@ -31,12 +34,20 @@ config HAVE_FTRACE_MCOUNT_RECORD
 config HAVE_HW_BRANCH_TRACER
 	bool
 
+config HAVE_FTRACE_SYSCALLS
+	bool
+
 config TRACER_MAX_TRACE
 	bool
 
 config RING_BUFFER
 	bool
 
+config FTRACE_NMI_ENTER
+       bool
+       depends on HAVE_FTRACE_NMI_ENTER
+       default y
+
 config TRACING
 	bool
 	select DEBUG_FS
@@ -44,13 +55,29 @@ config TRACING
 	select STACKTRACE if STACKTRACE_SUPPORT
 	select TRACEPOINTS
 	select NOP_TRACER
+	select BINARY_PRINTF
+
+#
+# Minimum requirements an architecture has to meet for us to
+# be able to offer generic tracing facilities:
+#
+config TRACING_SUPPORT
+	bool
+	# PPC32 has no irqflags tracing support, but it can use most of the
+	# tracers anyway, they were tested to build and work. Note that new
+	# exceptions to this list aren't welcomed, better implement the
+	# irqflags tracing for your architecture.
+	depends on TRACE_IRQFLAGS_SUPPORT || PPC32
+	depends on STACKTRACE_SUPPORT
+	default y
+
+if TRACING_SUPPORT
 
 menu "Tracers"
 
 config FUNCTION_TRACER
 	bool "Kernel Function Tracer"
 	depends on HAVE_FUNCTION_TRACER
-	depends on DEBUG_KERNEL
 	select FRAME_POINTER
 	select KALLSYMS
 	select TRACING
@@ -83,7 +110,6 @@ config IRQSOFF_TRACER
 	default n
 	depends on TRACE_IRQFLAGS_SUPPORT
 	depends on GENERIC_TIME
-	depends on DEBUG_KERNEL
 	select TRACE_IRQFLAGS
 	select TRACING
 	select TRACER_MAX_TRACE
@@ -106,7 +132,6 @@ config PREEMPT_TRACER
 	default n
 	depends on GENERIC_TIME
 	depends on PREEMPT
-	depends on DEBUG_KERNEL
 	select TRACING
 	select TRACER_MAX_TRACE
 	help
@@ -127,13 +152,13 @@ config SYSPROF_TRACER
 	bool "Sysprof Tracer"
 	depends on X86
 	select TRACING
+	select CONTEXT_SWITCH_TRACER
 	help
 	  This tracer provides the trace needed by the 'Sysprof' userspace
 	  tool.
 
 config SCHED_TRACER
 	bool "Scheduling Latency Tracer"
-	depends on DEBUG_KERNEL
 	select TRACING
 	select CONTEXT_SWITCH_TRACER
 	select TRACER_MAX_TRACE
@@ -143,16 +168,30 @@ config SCHED_TRACER
 
 config CONTEXT_SWITCH_TRACER
 	bool "Trace process context switches"
-	depends on DEBUG_KERNEL
 	select TRACING
 	select MARKERS
 	help
 	  This tracer gets called from the context switch and records
 	  all switching of tasks.
 
+config EVENT_TRACER
+	bool "Trace various events in the kernel"
+	select TRACING
+	help
+	  This tracer hooks to various trace points in the kernel
+	  allowing the user to pick and choose which trace point they
+	  want to trace.
+
+config FTRACE_SYSCALLS
+	bool "Trace syscalls"
+	depends on HAVE_FTRACE_SYSCALLS
+	select TRACING
+	select KALLSYMS
+	help
+	  Basic tracer to catch the syscall entry and exit events.
+
 config BOOT_TRACER
 	bool "Trace boot initcalls"
-	depends on DEBUG_KERNEL
 	select TRACING
 	select CONTEXT_SWITCH_TRACER
 	help
@@ -165,13 +204,11 @@ config BOOT_TRACER
 	  representation of the delays during initcalls - but the raw
 	  /debug/tracing/trace text output is readable too.
 
-	  ( Note that tracing self tests can't be enabled if this tracer is
-	    selected, because the self-tests are an initcall as well and that
-	    would invalidate the boot trace. )
+	  You must pass in ftrace=initcall to the kernel command line
+	  to enable this on bootup.
 
 config TRACE_BRANCH_PROFILING
 	bool "Trace likely/unlikely profiler"
-	depends on DEBUG_KERNEL
 	select TRACING
 	help
 	  This tracer profiles all the the likely and unlikely macros
@@ -224,7 +261,6 @@ config BRANCH_TRACER
 
 config POWER_TRACER
 	bool "Trace power consumption behavior"
-	depends on DEBUG_KERNEL
 	depends on X86
 	select TRACING
 	help
@@ -236,7 +272,6 @@ config POWER_TRACER
 config STACK_TRACER
 	bool "Trace max stack"
 	depends on HAVE_FUNCTION_TRACER
-	depends on DEBUG_KERNEL
 	select FUNCTION_TRACER
 	select STACKTRACE
 	select KALLSYMS
@@ -266,11 +301,66 @@ config HW_BRANCH_TRACER
 	  This tracer records all branches on the system in a circular
 	  buffer giving access to the last N branches for each cpu.
 
+config KMEMTRACE
+	bool "Trace SLAB allocations"
+	select TRACING
+	help
+	  kmemtrace provides tracing for slab allocator functions, such as
+	  kmalloc, kfree, kmem_cache_alloc, kmem_cache_free etc.. Collected
+	  data is then fed to the userspace application in order to analyse
+	  allocation hotspots, internal fragmentation and so on, making it
+	  possible to see how well an allocator performs, as well as debug
+	  and profile kernel code.
+
+	  This requires an userspace application to use. See
+	  Documentation/vm/kmemtrace.txt for more information.
+
+	  Saying Y will make the kernel somewhat larger and slower. However,
+	  if you disable kmemtrace at run-time or boot-time, the performance
+	  impact is minimal (depending on the arch the kernel is built for).
+
+	  If unsure, say N.
+
+config WORKQUEUE_TRACER
+	bool "Trace workqueues"
+	select TRACING
+	help
+	  The workqueue tracer provides some statistical informations
+          about each cpu workqueue thread such as the number of the
+          works inserted and executed since their creation. It can help
+          to evaluate the amount of work each of them have to perform.
+          For example it can help a developer to decide whether he should
+          choose a per cpu workqueue instead of a singlethreaded one.
+
+config BLK_DEV_IO_TRACE
+	bool "Support for tracing block io actions"
+	depends on SYSFS
+	depends on BLOCK
+	select RELAY
+	select DEBUG_FS
+	select TRACEPOINTS
+	select TRACING
+	select STACKTRACE
+	help
+	  Say Y here if you want to be able to trace the block layer actions
+	  on a given queue. Tracing allows you to see any traffic happening
+	  on a block device queue. For more information (and the userspace
+	  support tools needed), fetch the blktrace tools from:
+
+	  git://git.kernel.dk/blktrace.git
+
+	  Tracing also is possible using the ftrace interface, e.g.:
+
+	    echo 1 > /sys/block/sda/sda1/trace/enable
+	    echo blk > /sys/kernel/debug/tracing/current_tracer
+	    cat /sys/kernel/debug/tracing/trace_pipe
+
+	  If unsure, say N.
+
 config DYNAMIC_FTRACE
 	bool "enable/disable ftrace tracepoints dynamically"
 	depends on FUNCTION_TRACER
 	depends on HAVE_DYNAMIC_FTRACE
-	depends on DEBUG_KERNEL
 	default y
 	help
          This option will modify all the calls to ftrace dynamically
@@ -296,7 +386,7 @@ config FTRACE_SELFTEST
 
 config FTRACE_STARTUP_TEST
 	bool "Perform a startup test on ftrace"
-	depends on TRACING && DEBUG_KERNEL && !BOOT_TRACER
+	depends on TRACING
 	select FTRACE_SELFTEST
 	help
 	  This option performs a series of startup tests on ftrace. On bootup