23 files changed, 582 insertions, 164 deletions

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index d36f68b08acc..c674ee8f7fca 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -44,6 +44,10 @@ const char *ftrace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr,
 const char *ftrace_print_hex_seq(struct trace_seq *p,
                                  const unsigned char *buf, int len);
 
+const char *ftrace_print_array_seq(struct trace_seq *p,
+                                   const void *buf, int buf_len,
+                                   size_t el_size);
+
 struct trace_iterator;
 struct trace_event;
 
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 27609dfcce25..41bf65f04dd9 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -263,6 +263,14 @@
 #undef __print_hex
 #define __print_hex(buf, buf_len) ftrace_print_hex_seq(p, buf, buf_len)
 
+#undef __print_array
+#define __print_array(array, count, el_size)                            \
+        ({                                                              \
+                BUILD_BUG_ON(el_size != 1 && el_size != 2 &&            \
+                             el_size != 4 && el_size != 8);             \
+                ftrace_print_array_seq(p, array, count, el_size);       \
+        })
+
 #undef DECLARE_EVENT_CLASS
 #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)  \
 static notrace enum print_line_t                                        \
@@ -674,6 +682,7 @@ static inline void ftrace_test_probe_##call(void)			\
 #undef __get_dynamic_array_len
 #undef __get_str
 #undef __get_bitmask
+#undef __print_array
 
 #undef TP_printk
 #define TP_printk(fmt, args...) "\"" fmt "\", "  __stringify(args)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 224e768bdc73..45e5cb143d17 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5456,7 +5456,7 @@ static __init int ftrace_init_debugfs(void)
         struct dentry *d_tracer;
 
         d_tracer = tracing_init_dentry();
-        if (!d_tracer)
+        if (IS_ERR(d_tracer))
                 return 0;
 
         ftrace_init_dyn_debugfs(d_tracer);
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 7a4104cb95cb..5040d44fe5a3 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -9,7 +9,6 @@
 #include <linux/trace_seq.h>
 #include <linux/spinlock.h>
 #include <linux/irq_work.h>
-#include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/hardirq.h>
 #include <linux/kthread.h>      /* for self test */
@@ -23,7 +22,6 @@
 #include <linux/hash.h>
 #include <linux/list.h>
 #include <linux/cpu.h>
-#include <linux/fs.h>
 
 #include <asm/local.h>
 
@@ -447,7 +445,10 @@ int ring_buffer_print_page_header(struct trace_seq *s)
 struct rb_irq_work {
         struct irq_work                 work;
         wait_queue_head_t               waiters;
+        wait_queue_head_t               full_waiters;
         bool                            waiters_pending;
+        bool                            full_waiters_pending;
+        bool                            wakeup_full;
 };
 
 /*
@@ -529,6 +530,10 @@ static void rb_wake_up_waiters(struct irq_work *work)
         struct rb_irq_work *rbwork = container_of(work, struct rb_irq_work, work);
 
         wake_up_all(&rbwork->waiters);
+        if (rbwork->wakeup_full) {
+                rbwork->wakeup_full = false;
+                wake_up_all(&rbwork->full_waiters);
+        }
 }
 
 /**
@@ -553,9 +558,11 @@ int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool full)
          * data in any cpu buffer, or a specific buffer, put the
          * caller on the appropriate wait queue.
          */
-        if (cpu == RING_BUFFER_ALL_CPUS)
+        if (cpu == RING_BUFFER_ALL_CPUS) {
                 work = &buffer->irq_work;
-        else {
+                /* Full only makes sense on per cpu reads */
+                full = false;
+        } else {
                 if (!cpumask_test_cpu(cpu, buffer->cpumask))
                         return -ENODEV;
                 cpu_buffer = buffer->buffers[cpu];
@@ -564,7 +571,10 @@ int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool full)
 
 
         while (true) {
-                prepare_to_wait(&work->waiters, &wait, TASK_INTERRUPTIBLE);
+                if (full)
+                        prepare_to_wait(&work->full_waiters, &wait, TASK_INTERRUPTIBLE);
+                else
+                        prepare_to_wait(&work->waiters, &wait, TASK_INTERRUPTIBLE);
 
                 /*
                  * The events can happen in critical sections where
@@ -586,7 +596,10 @@ int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool full)
                  * that is necessary is that the wake up happens after
                  * a task has been queued. It's OK for spurious wake ups.
                  */
-                work->waiters_pending = true;
+                if (full)
+                        work->full_waiters_pending = true;
+                else
+                        work->waiters_pending = true;
 
                 if (signal_pending(current)) {
                         ret = -EINTR;
@@ -615,7 +628,10 @@ int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool full)
                 schedule();
         }
 
-        finish_wait(&work->waiters, &wait);
+        if (full)
+                finish_wait(&work->full_waiters, &wait);
+        else
+                finish_wait(&work->waiters, &wait);
 
         return ret;
 }
@@ -1230,6 +1246,7 @@ rb_allocate_cpu_buffer(struct ring_buffer *buffer, int nr_pages, int cpu)
         init_completion(&cpu_buffer->update_done);
         init_irq_work(&cpu_buffer->irq_work.work, rb_wake_up_waiters);
         init_waitqueue_head(&cpu_buffer->irq_work.waiters);
+        init_waitqueue_head(&cpu_buffer->irq_work.full_waiters);
 
         bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()),
                             GFP_KERNEL, cpu_to_node(cpu));
@@ -2801,6 +2818,8 @@ static void rb_commit(struct ring_buffer_per_cpu *cpu_buffer,
 static __always_inline void
 rb_wakeups(struct ring_buffer *buffer, struct ring_buffer_per_cpu *cpu_buffer)
 {
+        bool pagebusy;
+
         if (buffer->irq_work.waiters_pending) {
                 buffer->irq_work.waiters_pending = false;
                 /* irq_work_queue() supplies it's own memory barriers */
@@ -2812,6 +2831,15 @@ rb_wakeups(struct ring_buffer *buffer, struct ring_buffer_per_cpu *cpu_buffer)
                 /* irq_work_queue() supplies it's own memory barriers */
                 irq_work_queue(&cpu_buffer->irq_work.work);
         }
+
+        pagebusy = cpu_buffer->reader_page == cpu_buffer->commit_page;
+
+        if (!pagebusy && cpu_buffer->irq_work.full_waiters_pending) {
+                cpu_buffer->irq_work.wakeup_full = true;
+                cpu_buffer->irq_work.full_waiters_pending = false;
+                /* irq_work_queue() supplies it's own memory barriers */
+                irq_work_queue(&cpu_buffer->irq_work.work);
+        }
 }
 
 /**
diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c
index 3f9e328c30b5..13d945c0d03f 100644
--- a/kernel/trace/ring_buffer_benchmark.c
+++ b/kernel/trace/ring_buffer_benchmark.c
@@ -7,7 +7,7 @@
 #include <linux/completion.h>
 #include <linux/kthread.h>
 #include <linux/module.h>
-#include <linux/time.h>
+#include <linux/ktime.h>
 #include <asm/local.h>
 
 struct rb_page {
@@ -17,7 +17,7 @@ struct rb_page {
 };
 
 /* run time and sleep time in seconds */
-#define RUN_TIME        10
+#define RUN_TIME        10ULL
 #define SLEEP_TIME      10
 
 /* number of events for writer to wake up the reader */
@@ -212,8 +212,7 @@ static void ring_buffer_consumer(void)
 
 static void ring_buffer_producer(void)
 {
-        struct timeval start_tv;
-        struct timeval end_tv;
+        ktime_t start_time, end_time, timeout;
         unsigned long long time;
         unsigned long long entries;
         unsigned long long overruns;
@@ -227,7 +226,8 @@ static void ring_buffer_producer(void)
          * make the system stall)
          */
         trace_printk("Starting ring buffer hammer\n");
-        do_gettimeofday(&start_tv);
+        start_time = ktime_get();
+        timeout = ktime_add_ns(start_time, RUN_TIME * NSEC_PER_SEC);
         do {
                 struct ring_buffer_event *event;
                 int *entry;
@@ -244,7 +244,7 @@ static void ring_buffer_producer(void)
                                 ring_buffer_unlock_commit(buffer, event);
                         }
                 }
-                do_gettimeofday(&end_tv);
+                end_time = ktime_get();
 
                 cnt++;
                 if (consumer && !(cnt % wakeup_interval))
@@ -264,7 +264,7 @@ static void ring_buffer_producer(void)
                         cond_resched();
 #endif
 
-        } while (end_tv.tv_sec < (start_tv.tv_sec + RUN_TIME) && !kill_test);
+        } while (ktime_before(end_time, timeout) && !kill_test);
         trace_printk("End ring buffer hammer\n");
 
         if (consumer) {
@@ -280,9 +280,7 @@ static void ring_buffer_producer(void)
                 wait_for_completion(&read_done);
         }
 
-        time = end_tv.tv_sec - start_tv.tv_sec;
-        time *= USEC_PER_SEC;
-        time += (long long)((long)end_tv.tv_usec - (long)start_tv.tv_usec);
+        time = ktime_us_delta(end_time, start_time);
 
         entries = ring_buffer_entries(buffer);
         overruns = ring_buffer_overruns(buffer);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 4a9079b9f082..77b8dc528006 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2036,7 +2036,8 @@ void trace_printk_init_buffers(void)
 
         /* trace_printk() is for debug use only. Don't use it in production. */
 
-        pr_warning("\n**********************************************************\n");
+        pr_warning("\n");
+        pr_warning("**********************************************************\n");
         pr_warning("**   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **\n");
         pr_warning("**                                                      **\n");
         pr_warning("** trace_printk() being used. Allocating extra memory.  **\n");
@@ -4140,6 +4141,12 @@ static int tracing_set_tracer(struct trace_array *tr, const char *buf)
                 goto out;
         }
 
+        /* If trace pipe files are being read, we can't change the tracer */
+        if (tr->current_trace->ref) {
+                ret = -EBUSY;
+                goto out;
+        }
+
         trace_branch_disable();
 
         tr->current_trace->enabled--;
@@ -4326,17 +4333,7 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
         }
 
         trace_seq_init(&iter->seq);
-
-        /*
-         * We make a copy of the current tracer to avoid concurrent
-         * changes on it while we are reading.
-         */
-        iter->trace = kmalloc(sizeof(*iter->trace), GFP_KERNEL);
-        if (!iter->trace) {
-                ret = -ENOMEM;
-                goto fail;
-        }
-        *iter->trace = *tr->current_trace;
+        iter->trace = tr->current_trace;
 
         if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
                 ret = -ENOMEM;
@@ -4363,6 +4360,8 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
                 iter->trace->pipe_open(iter);
 
         nonseekable_open(inode, filp);
+
+        tr->current_trace->ref++;
 out:
         mutex_unlock(&trace_types_lock);
         return ret;
@@ -4382,6 +4381,8 @@ static int tracing_release_pipe(struct inode *inode, struct file *file)
 
         mutex_lock(&trace_types_lock);
 
+        tr->current_trace->ref--;
+
         if (iter->trace->pipe_close)
                 iter->trace->pipe_close(iter);
 
@@ -4389,7 +4390,6 @@ static int tracing_release_pipe(struct inode *inode, struct file *file)
 
         free_cpumask_var(iter->started);
         mutex_destroy(&iter->mutex);
-        kfree(iter->trace);
         kfree(iter);
 
         trace_array_put(tr);
@@ -4422,7 +4422,7 @@ tracing_poll_pipe(struct file *filp, poll_table *poll_table)
         return trace_poll(iter, filp, poll_table);
 }
 
-/* Must be called with trace_types_lock mutex held. */
+/* Must be called with iter->mutex held. */
 static int tracing_wait_pipe(struct file *filp)
 {
         struct trace_iterator *iter = filp->private_data;
@@ -4467,7 +4467,6 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
                   size_t cnt, loff_t *ppos)
 {
         struct trace_iterator *iter = filp->private_data;
-        struct trace_array *tr = iter->tr;
         ssize_t sret;
 
         /* return any leftover data */
@@ -4477,12 +4476,6 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
 
         trace_seq_init(&iter->seq);
 
-        /* copy the tracer to avoid using a global lock all around */
-        mutex_lock(&trace_types_lock);
-        if (unlikely(iter->trace->name != tr->current_trace->name))
-                *iter->trace = *tr->current_trace;
-        mutex_unlock(&trace_types_lock);
-
         /*
          * Avoid more than one consumer on a single file descriptor
          * This is just a matter of traces coherency, the ring buffer itself
@@ -4642,7 +4635,6 @@ static ssize_t tracing_splice_read_pipe(struct file *filp,
                 .ops            = &tracing_pipe_buf_ops,
                 .spd_release    = tracing_spd_release_pipe,
         };
-        struct trace_array *tr = iter->tr;
         ssize_t ret;
         size_t rem;
         unsigned int i;
@@ -4650,12 +4642,6 @@ static ssize_t tracing_splice_read_pipe(struct file *filp,
         if (splice_grow_spd(pipe, &spd))
                 return -ENOMEM;
 
-        /* copy the tracer to avoid using a global lock all around */
-        mutex_lock(&trace_types_lock);
-        if (unlikely(iter->trace->name != tr->current_trace->name))
-                *iter->trace = *tr->current_trace;
-        mutex_unlock(&trace_types_lock);
-
         mutex_lock(&iter->mutex);
 
         if (iter->trace->splice_read) {
@@ -4942,7 +4928,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
         *fpos += written;
 
  out_unlock:
-        for (i = 0; i < nr_pages; i++){
+        for (i = nr_pages - 1; i >= 0; i--) {
                 kunmap_atomic(map_page[i]);
                 put_page(pages[i]);
         }
@@ -5331,6 +5317,8 @@ static int tracing_buffers_open(struct inode *inode, struct file *filp)
 
         filp->private_data = info;
 
+        tr->current_trace->ref++;
+
         mutex_unlock(&trace_types_lock);
 
         ret = nonseekable_open(inode, filp);
@@ -5361,21 +5349,16 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
         if (!count)
                 return 0;
 
-        mutex_lock(&trace_types_lock);
-
 #ifdef CONFIG_TRACER_MAX_TRACE
-        if (iter->snapshot && iter->tr->current_trace->use_max_tr) {
-                size = -EBUSY;
-                goto out_unlock;
-        }
+        if (iter->snapshot && iter->tr->current_trace->use_max_tr)
+                return -EBUSY;
 #endif
 
         if (!info->spare)
                 info->spare = ring_buffer_alloc_read_page(iter->trace_buffer->buffer,
                                                           iter->cpu_file);
-        size = -ENOMEM;
         if (!info->spare)
-                goto out_unlock;
+                return -ENOMEM;
 
         /* Do we have previous read data to read? */
         if (info->read < PAGE_SIZE)
@@ -5391,21 +5374,16 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
 
         if (ret < 0) {
                 if (trace_empty(iter)) {
-                        if ((filp->f_flags & O_NONBLOCK)) {
-                                size = -EAGAIN;
-                                goto out_unlock;
-                        }
-                        mutex_unlock(&trace_types_lock);
+                        if ((filp->f_flags & O_NONBLOCK))
+                                return -EAGAIN;
+
                         ret = wait_on_pipe(iter, false);
-                        mutex_lock(&trace_types_lock);
-                        if (ret) {
-                                size = ret;
-                                goto out_unlock;
-                        }
+                        if (ret)
+                                return ret;
+
                         goto again;
                 }
-                size = 0;
-                goto out_unlock;
+                return 0;
         }
 
         info->read = 0;
@@ -5415,18 +5393,14 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
                 size = count;
 
         ret = copy_to_user(ubuf, info->spare + info->read, size);
-        if (ret == size) {
-                size = -EFAULT;
-                goto out_unlock;
-        }
+        if (ret == size)
+                return -EFAULT;
+
         size -= ret;
 
         *ppos += size;
         info->read += size;
 
- out_unlock:
-        mutex_unlock(&trace_types_lock);
-
         return size;
 }
 
@@ -5437,6 +5411,8 @@ static int tracing_buffers_release(struct inode *inode, struct file *file)
 
         mutex_lock(&trace_types_lock);
 
+        iter->tr->current_trace->ref--;
+
         __trace_array_put(iter->tr);
 
         if (info->spare)
@@ -5522,30 +5498,20 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
         int entries, size, i;
         ssize_t ret = 0;
 
-        mutex_lock(&trace_types_lock);
-
 #ifdef CONFIG_TRACER_MAX_TRACE
-        if (iter->snapshot && iter->tr->current_trace->use_max_tr) {
-                ret = -EBUSY;
-                goto out;
-        }
+        if (iter->snapshot && iter->tr->current_trace->use_max_tr)
+                return -EBUSY;
 #endif
 
-        if (splice_grow_spd(pipe, &spd)) {
-                ret = -ENOMEM;
-                goto out;
-        }
+        if (splice_grow_spd(pipe, &spd))
+                return -ENOMEM;
 
-        if (*ppos & (PAGE_SIZE - 1)) {
-                ret = -EINVAL;
-                goto out;
-        }
+        if (*ppos & (PAGE_SIZE - 1))
+                return -EINVAL;
 
         if (len & (PAGE_SIZE - 1)) {
-                if (len < PAGE_SIZE) {
-                        ret = -EINVAL;
-                        goto out;
-                }
+                if (len < PAGE_SIZE)
+                        return -EINVAL;
                 len &= PAGE_MASK;
         }
 
@@ -5606,25 +5572,20 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
         /* did we read anything? */
         if (!spd.nr_pages) {
                 if (ret)
-                        goto out;
+                        return ret;
+
+                if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
+                        return -EAGAIN;
 
-                if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK)) {
-                        ret = -EAGAIN;
-                        goto out;
-                }
-                mutex_unlock(&trace_types_lock);
                 ret = wait_on_pipe(iter, true);
-                mutex_lock(&trace_types_lock);
                 if (ret)
-                        goto out;
+                        return ret;
 
                 goto again;
         }
 
         ret = splice_to_pipe(pipe, &spd);
         splice_shrink_spd(&spd);
-out:
-        mutex_unlock(&trace_types_lock);
 
         return ret;
 }
@@ -5854,28 +5815,11 @@ static __init int register_snapshot_cmd(void)
 static inline __init int register_snapshot_cmd(void) { return 0; }
 #endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
 
-struct dentry *tracing_init_dentry_tr(struct trace_array *tr)
+static struct dentry *tracing_get_dentry(struct trace_array *tr)
 {
-        if (tr->dir)
-                return tr->dir;
-
-        if (!debugfs_initialized())
-                return NULL;
-
-        if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
-                tr->dir = debugfs_create_dir("tracing", NULL);
-
-        if (!tr->dir)
-                pr_warn_once("Could not create debugfs directory 'tracing'\n");
-
         return tr->dir;
 }
 
-struct dentry *tracing_init_dentry(void)
-{
-        return tracing_init_dentry_tr(&global_trace);
-}
-
 static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
 {
         struct dentry *d_tracer;
@@ -5883,8 +5827,8 @@ static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
         if (tr->percpu_dir)
                 return tr->percpu_dir;
 
-        d_tracer = tracing_init_dentry_tr(tr);
-        if (!d_tracer)
+        d_tracer = tracing_get_dentry(tr);
+        if (IS_ERR(d_tracer))
                 return NULL;
 
         tr->percpu_dir = debugfs_create_dir("per_cpu", d_tracer);
@@ -6086,8 +6030,8 @@ static struct dentry *trace_options_init_dentry(struct trace_array *tr)
         if (tr->options)
                 return tr->options;
 
-        d_tracer = tracing_init_dentry_tr(tr);
-        if (!d_tracer)
+        d_tracer = tracing_get_dentry(tr);
+        if (IS_ERR(d_tracer))
                 return NULL;
 
         tr->options = debugfs_create_dir("options", d_tracer);
@@ -6416,7 +6360,7 @@ static int instance_delete(const char *name)
                 goto out_unlock;
 
         ret = -EBUSY;
-        if (tr->ref)
+        if (tr->ref || (tr->current_trace && tr->current_trace->ref))
                 goto out_unlock;
 
         list_del(&tr->list);
@@ -6571,6 +6515,33 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
 
 }
 
+/**
+ * tracing_init_dentry - initialize top level trace array
+ *
+ * This is called when creating files or directories in the tracing
+ * directory. It is called via fs_initcall() by any of the boot up code
+ * and expects to return the dentry of the top level tracing directory.
+ */
+struct dentry *tracing_init_dentry(void)
+{
+        struct trace_array *tr = &global_trace;
+
+        if (tr->dir)
+                return tr->dir;
+
+        if (WARN_ON(!debugfs_initialized()))
+                return ERR_PTR(-ENODEV);
+
+        tr->dir = debugfs_create_dir("tracing", NULL);
+
+        if (!tr->dir) {
+                pr_warn_once("Could not create debugfs directory 'tracing'\n");
+                return ERR_PTR(-ENOMEM);
+        }
+
+        return tr->dir;
+}
+
 static __init int tracer_init_debugfs(void)
 {
         struct dentry *d_tracer;
@@ -6578,7 +6549,7 @@ static __init int tracer_init_debugfs(void)
         trace_access_lock_init();
 
         d_tracer = tracing_init_dentry();
-        if (!d_tracer)
+        if (IS_ERR(d_tracer))
                 return 0;
 
         init_tracer_debugfs(&global_trace, d_tracer);
@@ -6811,7 +6782,6 @@ __init static int tracer_alloc_buffers(void)
         int ring_buf_size;
         int ret = -ENOMEM;
 
-
         if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
                 goto out;
 
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 8de48bac1ce2..dd8205a35760 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -388,6 +388,7 @@ struct tracer {
         struct tracer           *next;
         struct tracer_flags     *flags;
         int                     enabled;
+        int                     ref;
         bool                    print_max;
         bool                    allow_instances;
 #ifdef CONFIG_TRACER_MAX_TRACE
@@ -541,7 +542,6 @@ struct dentry *trace_create_file(const char *name,
                                  void *data,
                                  const struct file_operations *fops);
 
-struct dentry *tracing_init_dentry_tr(struct trace_array *tr);
 struct dentry *tracing_init_dentry(void);
 
 struct ring_buffer_event;
diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index 7d6e2afde669..57cbf1efdd44 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -7,7 +7,6 @@
 #include <linux/seq_file.h>
 #include <linux/spinlock.h>
 #include <linux/irqflags.h>
-#include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/module.h>
 #include <linux/ftrace.h>
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index b03a0ea77b99..db54dda10ccc 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2531,7 +2531,7 @@ static __init int event_trace_init(void)
                 return -ENODEV;
 
         d_tracer = tracing_init_dentry();
-        if (!d_tracer)
+        if (IS_ERR(d_tracer))
                 return 0;
 
         entry = debugfs_create_file("available_events", 0444, d_tracer,
diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
index d4ddde28a81a..12e2b99be862 100644
--- a/kernel/trace/trace_export.c
+++ b/kernel/trace/trace_export.c
@@ -6,12 +6,10 @@
 #include <linux/stringify.h>
 #include <linux/kallsyms.h>
 #include <linux/seq_file.h>
-#include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
 #include <linux/module.h>
 #include <linux/init.h>
-#include <linux/fs.h>
 
 #include "trace_output.h"
 
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index ba476009e5de..2d25ad1526bb 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -1437,7 +1437,7 @@ static __init int init_graph_debugfs(void)
         struct dentry *d_tracer;
 
         d_tracer = tracing_init_dentry();
-        if (!d_tracer)
+        if (IS_ERR(d_tracer))
                 return 0;
 
         trace_create_file("max_graph_depth", 0644, d_tracer,
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 9bb104f748d0..8523ea345f2b 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -10,11 +10,9 @@
  *  Copyright (C) 2004 Nadia Yvette Chambers
  */
 #include <linux/kallsyms.h>
-#include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/module.h>
 #include <linux/ftrace.h>
-#include <linux/fs.h>
 
 #include "trace.h"
 
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 296079ae6583..d73f565b4e06 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1320,7 +1320,7 @@ static __init int init_kprobe_trace(void)
                 return -EINVAL;
 
         d_tracer = tracing_init_dentry();
-        if (!d_tracer)
+        if (IS_ERR(d_tracer))
                 return 0;
 
         entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
diff --git a/kernel/trace/trace_nop.c b/kernel/trace/trace_nop.c
index fcf0a9e48916..8bb2071474dd 100644
--- a/kernel/trace/trace_nop.c
+++ b/kernel/trace/trace_nop.c
@@ -6,8 +6,6 @@
  */
 
 #include <linux/module.h>
-#include <linux/fs.h>
-#include <linux/debugfs.h>
 #include <linux/ftrace.h>
 
 #include "trace.h"
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index b77b9a697619..692bf7184c8c 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -177,6 +177,50 @@ ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len)
 }
 EXPORT_SYMBOL(ftrace_print_hex_seq);
 
+const char *
+ftrace_print_array_seq(struct trace_seq *p, const void *buf, int buf_len,
+                       size_t el_size)
+{
+        const char *ret = trace_seq_buffer_ptr(p);
+        const char *prefix = "";
+        void *ptr = (void *)buf;
+
+        trace_seq_putc(p, '{');
+
+        while (ptr < buf + buf_len) {
+                switch (el_size) {
+                case 1:
+                        trace_seq_printf(p, "%s0x%x", prefix,
+                                         *(u8 *)ptr);
+                        break;
+                case 2:
+                        trace_seq_printf(p, "%s0x%x", prefix,
+                                         *(u16 *)ptr);
+                        break;
+                case 4:
+                        trace_seq_printf(p, "%s0x%x", prefix,
+                                         *(u32 *)ptr);
+                        break;
+                case 8:
+                        trace_seq_printf(p, "%s0x%llx", prefix,
+                                         *(u64 *)ptr);
+                        break;
+                default:
+                        trace_seq_printf(p, "BAD SIZE:%zu 0x%x", el_size,
+                                         *(u8 *)ptr);
+                        el_size = 1;
+                }
+                prefix = ",";
+                ptr += el_size;
+        }
+
+        trace_seq_putc(p, '}');
+        trace_seq_putc(p, 0);
+
+        return ret;
+}
+EXPORT_SYMBOL(ftrace_print_array_seq);
+
 int ftrace_raw_output_prep(struct trace_iterator *iter,
                            struct trace_event *trace_event)
 {
diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
index c4e70b6bd7fa..36c1455b7567 100644
--- a/kernel/trace/trace_printk.c
+++ b/kernel/trace/trace_printk.c
@@ -5,7 +5,6 @@
  *
  */
 #include <linux/seq_file.h>
-#include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/kernel.h>
 #include <linux/ftrace.h>
@@ -15,7 +14,6 @@
 #include <linux/ctype.h>
 #include <linux/list.h>
 #include <linux/slab.h>
-#include <linux/fs.h>
 
 #include "trace.h"
 
@@ -349,7 +347,7 @@ static __init int init_trace_printk_function_export(void)
         struct dentry *d_tracer;
 
         d_tracer = tracing_init_dentry();
-        if (!d_tracer)
+        if (IS_ERR(d_tracer))
                 return 0;
 
         trace_create_file("printk_formats", 0444, d_tracer,
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index 2e293beb186e..419ca37e72c9 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -5,8 +5,6 @@
  *
  */
 #include <linux/module.h>
-#include <linux/fs.h>
-#include <linux/debugfs.h>
 #include <linux/kallsyms.h>
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 8fb84b362816..d6e1003724e9 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -10,8 +10,6 @@
  *  Copyright (C) 2004 Nadia Yvette Chambers
  */
 #include <linux/module.h>
-#include <linux/fs.h>
-#include <linux/debugfs.h>
 #include <linux/kallsyms.h>
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 16eddb308c33..c3e4fcfddd45 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -7,12 +7,10 @@
 #include <linux/seq_file.h>
 #include <linux/spinlock.h>
 #include <linux/uaccess.h>
-#include <linux/debugfs.h>
 #include <linux/ftrace.h>
 #include <linux/module.h>
 #include <linux/sysctl.h>
 #include <linux/init.h>
-#include <linux/fs.h>
 
 #include <asm/setup.h>
 
@@ -462,7 +460,7 @@ static __init int stack_trace_init(void)
         struct dentry *d_tracer;
 
         d_tracer = tracing_init_dentry();
-        if (!d_tracer)
+        if (IS_ERR(d_tracer))
                 return 0;
 
         trace_create_file("stack_max_size", 0644, d_tracer,
diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index 7af67360b330..75e19e86c954 100644
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -276,7 +276,7 @@ static int tracing_stat_init(void)
         struct dentry *d_tracing;
 
         d_tracing = tracing_init_dentry();
-        if (!d_tracing)
+        if (IS_ERR(d_tracing))
                 return 0;
 
         stat_dir = debugfs_create_dir("trace_stat", d_tracing);
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index b11441321e7a..7dc1c8abecd6 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -1321,7 +1321,7 @@ static __init int init_uprobe_trace(void)
         struct dentry *d_tracer;
 
         d_tracer = tracing_init_dentry();
-        if (!d_tracer)
+        if (IS_ERR(d_tracer))
                 return 0;
 
         trace_create_file("uprobe_events", 0644, d_tracer,
diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c
index aabc4e970911..880a7d1d27d2 100644
--- a/samples/trace_events/trace-events-sample.c
+++ b/samples/trace_events/trace-events-sample.c
@@ -10,12 +10,38 @@
 #define CREATE_TRACE_POINTS
 #include "trace-events-sample.h"
 
+static const char *random_strings[] = {
+        "Mother Goose",
+        "Snoopy",
+        "Gandalf",
+        "Frodo",
+        "One ring to rule them all"
+};
 
 static void simple_thread_func(int cnt)
 {
+        int array[6];
+        int len = cnt % 5;
+        int i;
+
         set_current_state(TASK_INTERRUPTIBLE);
         schedule_timeout(HZ);
-        trace_foo_bar("hello", cnt);
+
+        for (i = 0; i < len; i++)
+                array[i] = i + 1;
+        array[i] = 0;
+
+        /* Silly tracepoints */
+        trace_foo_bar("hello", cnt, array, random_strings[len],
+                      tsk_cpus_allowed(current));
+
+        trace_foo_with_template_simple("HELLO", cnt);
+
+        trace_foo_bar_with_cond("Some times print", cnt);
+
+        trace_foo_with_template_cond("prints other times", cnt);
+
+        trace_foo_with_template_print("I have to be different", cnt);
 }
 
 static int simple_thread(void *arg)
@@ -29,6 +55,53 @@ static int simple_thread(void *arg)
 }
 
 static struct task_struct *simple_tsk;
+static struct task_struct *simple_tsk_fn;
+
+static void simple_thread_func_fn(int cnt)
+{
+        set_current_state(TASK_INTERRUPTIBLE);
+        schedule_timeout(HZ);
+
+        /* More silly tracepoints */
+        trace_foo_bar_with_fn("Look at me", cnt);
+        trace_foo_with_template_fn("Look at me too", cnt);
+}
+
+static int simple_thread_fn(void *arg)
+{
+        int cnt = 0;
+
+        while (!kthread_should_stop())
+                simple_thread_func_fn(cnt++);
+
+        return 0;
+}
+
+static DEFINE_MUTEX(thread_mutex);
+
+void foo_bar_reg(void)
+{
+        pr_info("Starting thread for foo_bar_fn\n");
+        /*
+         * We shouldn't be able to start a trace when the module is
+         * unloading (there's other locks to prevent that). But
+         * for consistency sake, we still take the thread_mutex.
+         */
+        mutex_lock(&thread_mutex);
+        simple_tsk_fn = kthread_run(simple_thread_fn, NULL, "event-sample-fn");
+        mutex_unlock(&thread_mutex);
+}
+
+void foo_bar_unreg(void)
+{
+        pr_info("Killing thread for foo_bar_fn\n");
+        /* protect against module unloading */
+        mutex_lock(&thread_mutex);
+        if (simple_tsk_fn)
+                kthread_stop(simple_tsk_fn);
+        simple_tsk_fn = NULL;
+        mutex_unlock(&thread_mutex);
+}
 
 static int __init trace_event_init(void)
 {
@@ -42,6 +115,11 @@ static int __init trace_event_init(void)
 static void __exit trace_event_exit(void)
 {
         kthread_stop(simple_tsk);
+        mutex_lock(&thread_mutex);
+        if (simple_tsk_fn)
+                kthread_stop(simple_tsk_fn);
+        simple_tsk_fn = NULL;
+        mutex_unlock(&thread_mutex);
 }
 
 module_init(trace_event_init);
diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index 476429281389..a2c8b02b6359 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -1,6 +1,6 @@
 /*
  * If TRACE_SYSTEM is defined, that will be the directory created
- * in the ftrace directory under /sys/kernel/debug/tracing/events/<system>
+ * in the ftrace directory under /sys/kernel/tracing/events/<system>
  *
  * The define_trace.h below will also look for a file name of
  * TRACE_SYSTEM.h where TRACE_SYSTEM is what is defined here.
@@ -54,45 +54,347 @@
  *    Here it is simply "foo, bar".
  *
  * struct:  This defines the way the data will be stored in the ring buffer.
- *    There are currently two types of elements. __field and __array.
- *    a __field is broken up into (type, name). Where type can be any
- *    primitive type (integer, long or pointer). __field_struct() can
- *    be any static complex data value (struct, union, but not an array).
- *    For an array. there are three fields. (type, name, size). The
- *    type of elements in the array, the name of the field and the size
- *    of the array.
+ *          The items declared here become part of a special structure
+ *          called "__entry", which can be used in the fast_assign part of the
+ *          TRACE_EVENT macro.
+ *
+ *      Here are the currently defined types you can use:
+ *
+ *   __field : Is broken up into type and name. Where type can be any
+ *         primitive type (integer, long or pointer).
+ *
+ *        __field(int, foo)
+ *
+ *        __entry->foo = 5;
+ *
+ *   __field_struct : This can be any static complex data type (struct, union
+ *         but not an array). Be careful using complex types, as each
+ *         event is limited in size, and copying large amounts of data
+ *         into the ring buffer can slow things down.
+ *
+ *         __field_struct(struct bar, foo)
+ *
+ *         __entry->bar.x = y;
+
+ *   __array: There are three fields (type, name, size). The type is the
+ *         type of elements in teh array, the name is the name of the array.
+ *         size is the number of items in the array (not the total size).
+ *
+ *         __array( char, foo, 10) is the same as saying: char foo[10];
+ *
+ *         Assigning arrays can be done like any array:
+ *
+ *         __entry->foo[0] = 'a';
+ *
+ *         memcpy(__entry->foo, bar, 10);
+ *
+ *   __dynamic_array: This is similar to array, but can vary is size from
+ *         instance to instance of the tracepoint being called.
+ *         Like __array, this too has three elements (type, name, size);
+ *         type is the type of the element, name is the name of the array.
+ *         The size is different than __array. It is not a static number,
+ *         but the algorithm to figure out the length of the array for the
+ *         specific instance of tracepoint. Again, size is the numebr of
+ *         items in the array, not the total length in bytes.
+ *
+ *         __dynamic_array( int, foo, bar) is similar to: int foo[bar];
+ *
+ *         Note, unlike arrays, you must use the __get_dynamic_array() macro
+ *         to access the array.
+ *
+ *         memcpy(__get_dynamic_array(foo), bar, 10);
+ *
+ *         Notice, that "__entry" is not needed here.
+ *
+ *   __string: This is a special kind of __dynamic_array. It expects to
+ *         have a nul terminated character array passed to it (it allows
+ *         for NULL too, which would be converted into "(null)"). __string
+ *         takes two paramenter (name, src), where name is the name of
+ *         the string saved, and src is the string to copy into the
+ *         ring buffer.
+ *
+ *         __string(foo, bar)  is similar to:  strcpy(foo, bar)
+ *
+ *         To assign a string, use the helper macro __assign_str().
+ *
+ *         __assign_str(foo, bar);
+ *
+ *         In most cases, the __assign_str() macro will take the same
+ *         parameters as the __string() macro had to declare the string.
+ *
+ *   __bitmask: This is another kind of __dynamic_array, but it expects
+ *         an array of longs, and the number of bits to parse. It takes
+ *         two parameters (name, nr_bits), where name is the name of the
+ *         bitmask to save, and the nr_bits is the number of bits to record.
+ *
+ *         __bitmask(target_cpu, nr_cpumask_bits)
+ *
+ *         To assign a bitmask, use the __assign_bitmask() helper macro.
+ *
+ *         __assign_bitmask(target_cpus, cpumask_bits(bar), nr_cpumask_bits);
  *
- *    __array( char, foo, 10) is the same as saying   char foo[10].
  *
  * fast_assign: This is a C like function that is used to store the items
- *    into the ring buffer.
+ *    into the ring buffer. A special variable called "__entry" will be the
+ *    structure that points into the ring buffer and has the same fields as
+ *    described by the struct part of TRACE_EVENT above.
  *
  * printk: This is a way to print out the data in pretty print. This is
  *    useful if the system crashes and you are logging via a serial line,
  *    the data can be printed to the console using this "printk" method.
+ *    This is also used to print out the data from the trace files.
+ *    Again, the __entry macro is used to access the data from the ring buffer.
+ *
+ *    Note, __dynamic_array, __string, and __bitmask require special helpers
+ *       to access the data.
+ *
+ *      For __dynamic_array(int, foo, bar) use __get_dynamic_array(foo)
+ *            Use __get_dynamic_array_len(foo) to get the length of the array
+ *            saved.
+ *
+ *      For __string(foo, bar) use __get_str(foo)
+ *
+ *      For __bitmask(target_cpus, nr_cpumask_bits) use __get_bitmask(target_cpus)
+ *
  *
  * Note, that for both the assign and the printk, __entry is the handler
  * to the data structure in the ring buffer, and is defined by the
  * TP_STRUCT__entry.
  */
+
+/*
+ * It is OK to have helper functions in the file, but they need to be protected
+ * from being defined more than once. Remember, this file gets included more
+ * than once.
+ */
+#ifndef __TRACE_EVENT_SAMPLE_HELPER_FUNCTIONS
+#define __TRACE_EVENT_SAMPLE_HELPER_FUNCTIONS
+static inline int __length_of(const int *list)
+{
+        int i;
+
+        if (!list)
+                return 0;
+
+        for (i = 0; list[i]; i++)
+                ;
+        return i;
+}
+#endif
+
 TRACE_EVENT(foo_bar,
 
-        TP_PROTO(char *foo, int bar),
+        TP_PROTO(const char *foo, int bar, const int *lst,
+                 const char *string, const struct cpumask *mask),
 
-        TP_ARGS(foo, bar),
+        TP_ARGS(foo, bar, lst, string, mask),
 
         TP_STRUCT__entry(
                 __array(        char,   foo,    10              )
                 __field(        int,    bar                     )
+                __dynamic_array(int,    list,   __length_of(lst))
+                __string(       str,    string                  )
+                __bitmask(      cpus,   num_possible_cpus()     )
         ),
 
         TP_fast_assign(
                 strlcpy(__entry->foo, foo, 10);
                 __entry->bar    = bar;
+                memcpy(__get_dynamic_array(list), lst,
+                       __length_of(lst) * sizeof(int));
+                __assign_str(str, string);
+                __assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus());
+        ),
+
+        TP_printk("foo %s %d %s %s (%s)", __entry->foo, __entry->bar,
+                  __print_array(__get_dynamic_array(list),
+                                __get_dynamic_array_len(list),
+                                sizeof(int)),
+                  __get_str(str), __get_bitmask(cpus))
+);
+
+/*
+ * There may be a case where a tracepoint should only be called if
+ * some condition is set. Otherwise the tracepoint should not be called.
+ * But to do something like:
+ *
+ *  if (cond)
+ *     trace_foo();
+ *
+ * Would cause a little overhead when tracing is not enabled, and that
+ * overhead, even if small, is not something we want. As tracepoints
+ * use static branch (aka jump_labels), where no branch is taken to
+ * skip the tracepoint when not enabled, and a jmp is placed to jump
+ * to the tracepoint code when it is enabled, having a if statement
+ * nullifies that optimization. It would be nice to place that
+ * condition within the static branch. This is where TRACE_EVENT_CONDITION
+ * comes in.
+ *
+ * TRACE_EVENT_CONDITION() is just like TRACE_EVENT, except it adds another
+ * parameter just after args. Where TRACE_EVENT has:
+ *
+ * TRACE_EVENT(name, proto, args, struct, assign, printk)
+ *
+ * the CONDITION version has:
+ *
+ * TRACE_EVENT_CONDITION(name, proto, args, cond, struct, assign, printk)
+ *
+ * Everything is the same as TRACE_EVENT except for the new cond. Think
+ * of the cond variable as:
+ *
+ *   if (cond)
+ *      trace_foo_bar_with_cond();
+ *
+ * Except that the logic for the if branch is placed after the static branch.
+ * That is, the if statement that processes the condition will not be
+ * executed unless that traecpoint is enabled. Otherwise it still remains
+ * a nop.
+ */
+TRACE_EVENT_CONDITION(foo_bar_with_cond,
+
+        TP_PROTO(const char *foo, int bar),
+
+        TP_ARGS(foo, bar),
+
+        TP_CONDITION(!(bar % 10)),
+
+        TP_STRUCT__entry(
+                __string(       foo,    foo             )
+                __field(        int,    bar                     )
+        ),
+
+        TP_fast_assign(
+                __assign_str(foo, foo);
+                __entry->bar    = bar;
+        ),
+
+        TP_printk("foo %s %d", __get_str(foo), __entry->bar)
+);
+
+void foo_bar_reg(void);
+void foo_bar_unreg(void);
+
+/*
+ * Now in the case that some function needs to be called when the
+ * tracepoint is enabled and/or when it is disabled, the
+ * TRACE_EVENT_FN() serves this purpose. This is just like TRACE_EVENT()
+ * but adds two more parameters at the end:
+ *
+ * TRACE_EVENT_FN( name, proto, args, struct, assign, printk, reg, unreg)
+ *
+ * reg and unreg are functions with the prototype of:
+ *
+ *    void reg(void)
+ *
+ * The reg function gets called before the tracepoint is enabled, and
+ * the unreg function gets called after the tracepoint is disabled.
+ *
+ * Note, reg and unreg are allowed to be NULL. If you only need to
+ * call a function before enabling, or after disabling, just set one
+ * function and pass in NULL for the other parameter.
+ */
+TRACE_EVENT_FN(foo_bar_with_fn,
+
+        TP_PROTO(const char *foo, int bar),
+
+        TP_ARGS(foo, bar),
+
+        TP_STRUCT__entry(
+                __string(       foo,    foo             )
+                __field(        int,    bar             )
+        ),
+
+        TP_fast_assign(
+                __assign_str(foo, foo);
+                __entry->bar    = bar;
+        ),
+
+        TP_printk("foo %s %d", __get_str(foo), __entry->bar),
+
+        foo_bar_reg, foo_bar_unreg
+);
+
+/*
+ * Each TRACE_EVENT macro creates several helper functions to produce
+ * the code to add the tracepoint, create the files in the trace
+ * directory, hook it to perf, assign the values and to print out
+ * the raw data from the ring buffer. To prevent too much bloat,
+ * if there are more than one tracepoint that uses the same format
+ * for the proto, args, struct, assign and printk, and only the name
+ * is different, it is highly recommended to use the DECLARE_EVENT_CLASS
+ *
+ * DECLARE_EVENT_CLASS() macro creates most of the functions for the
+ * tracepoint. Then DEFINE_EVENT() is use to hook a tracepoint to those
+ * functions. This DEFINE_EVENT() is an instance of the class and can
+ * be enabled and disabled separately from other events (either TRACE_EVENT
+ * or other DEFINE_EVENT()s).
+ *
+ * Note, TRACE_EVENT() itself is simply defined as:
+ *
+ * #define TRACE_EVENT(name, proto, args, tstruct, assign, printk)  \
+ *  DEFINE_EVENT_CLASS(name, proto, args, tstruct, assign, printk); \
+ *  DEFINE_EVENT(name, name, proto, args)
+ *
+ * The DEFINE_EVENT() also can be declared with conditions and reg functions:
+ *
+ * DEFINE_EVENT_CONDITION(template, name, proto, args, cond);
+ * DEFINE_EVENT_FN(template, name, proto, args, reg, unreg);
+ */
+DECLARE_EVENT_CLASS(foo_template,
+
+        TP_PROTO(const char *foo, int bar),
+
+        TP_ARGS(foo, bar),
+
+        TP_STRUCT__entry(
+                __string(       foo,    foo             )
+                __field(        int,    bar             )
+        ),
+
+        TP_fast_assign(
+                __assign_str(foo, foo);
+                __entry->bar    = bar;
         ),
 
-        TP_printk("foo %s %d", __entry->foo, __entry->bar)
+        TP_printk("foo %s %d", __get_str(foo), __entry->bar)
 );
+
+/*
+ * Here's a better way for the previous samples (except, the first
+ * exmaple had more fields and could not be used here).
+ */
+DEFINE_EVENT(foo_template, foo_with_template_simple,
+        TP_PROTO(const char *foo, int bar),
+        TP_ARGS(foo, bar));
+
+DEFINE_EVENT_CONDITION(foo_template, foo_with_template_cond,
+        TP_PROTO(const char *foo, int bar),
+        TP_ARGS(foo, bar),
+        TP_CONDITION(!(bar % 8)));
+
+
+DEFINE_EVENT_FN(foo_template, foo_with_template_fn,
+        TP_PROTO(const char *foo, int bar),
+        TP_ARGS(foo, bar),
+        foo_bar_reg, foo_bar_unreg);
+
+/*
+ * Anytime two events share basically the same values and have
+ * the same output, use the DECLARE_EVENT_CLASS() and DEFINE_EVENT()
+ * when ever possible.
+ */
+
+/*
+ * If the event is similar to the DECLARE_EVENT_CLASS, but you need
+ * to have a different output, then use DEFINE_EVENT_PRINT() which
+ * lets you override the TP_printk() of the class.
+ */
+
+DEFINE_EVENT_PRINT(foo_template, foo_with_template_print,
+        TP_PROTO(const char *foo, int bar),
+        TP_ARGS(foo, bar),
+        TP_printk("bar %s %d", __get_str(foo), __entry->bar));
+
 #endif
 
 /***** NOTICE! The #if protection ends here. *****/