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;
#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 \
#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)
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);
#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 */
#include <linux/hash.h>
#include <linux/list.h>
#include <linux/cpu.h>
-#include <linux/fs.h>
#include <asm/local.h>
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;
};
/*
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);
+ }
}
/**
* 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];
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
* 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;
schedule();
}
- finish_wait(&work->waiters, &wait);
+ if (full)
+ finish_wait(&work->full_waiters, &wait);
+ else
+ finish_wait(&work->waiters, &wait);
return ret;
}
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));
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 */
/* 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);
+ }
}
/**
#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 {
};
/* 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 */
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;
* 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;
ring_buffer_unlock_commit(buffer, event);
}
}
- do_gettimeofday(&end_tv);
+ end_time = ktime_get();
cnt++;
if (consumer && !(cnt % wakeup_interval))
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) {
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);
/* 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");
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--;
}
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;
iter->trace->pipe_open(iter);
nonseekable_open(inode, filp);
+
+ tr->current_trace->ref++;
out:
mutex_unlock(&trace_types_lock);
return ret;
mutex_lock(&trace_types_lock);
+ tr->current_trace->ref--;
+
if (iter->trace->pipe_close)
iter->trace->pipe_close(iter);
free_cpumask_var(iter->started);
mutex_destroy(&iter->mutex);
- kfree(iter->trace);
kfree(iter);
trace_array_put(tr);
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;
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 */
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
.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;
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) {
*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]);
}
filp->private_data = info;
+ tr->current_trace->ref++;
+
mutex_unlock(&trace_types_lock);
ret = nonseekable_open(inode, filp);
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)
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;
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;
}
mutex_lock(&trace_types_lock);
+ iter->tr->current_trace->ref--;
+
__trace_array_put(iter->tr);
if (info->spare)
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;
}
/* 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;
}
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;
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);
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);
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);
}
+/**
+ * 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;
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);
int ring_buf_size;
int ret = -ENOMEM;
-
if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
goto out;
struct tracer *next;
struct tracer_flags *flags;
int enabled;
+ int ref;
bool print_max;
bool allow_instances;
#ifdef CONFIG_TRACER_MAX_TRACE
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;
#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>
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,
#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"
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,
* 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"
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,
*/
#include <linux/module.h>
-#include <linux/fs.h>
-#include <linux/debugfs.h>
#include <linux/ftrace.h>
#include "trace.h"
}
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)
{
*
*/
#include <linux/seq_file.h>
-#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/kernel.h>
#include <linux/ftrace.h>
#include <linux/ctype.h>
#include <linux/list.h>
#include <linux/slab.h>
-#include <linux/fs.h>
#include "trace.h"
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,
*
*/
#include <linux/module.h>
-#include <linux/fs.h>
-#include <linux/debugfs.h>
#include <linux/kallsyms.h>
#include <linux/uaccess.h>
#include <linux/ftrace.h>
* 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>
#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>
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,
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);
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,
#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)
}
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)
{
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);
/*
* 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.
* 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. *****/
projects / linux-drm-fsl-dcu.git / commitdiff