Merge branches 'tracing/ftrace' and 'tracing/urgent' into tracing/core
Conflicts:
kernel/trace/ring_buffer.c
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index a6b8f9d..c04c433 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -18,6 +18,35 @@
#include "trace.h"
+/* Global flag to disable all recording to ring buffers */
+static int ring_buffers_off __read_mostly;
+
+/**
+ * tracing_on - enable all tracing buffers
+ *
+ * This function enables all tracing buffers that may have been
+ * disabled with tracing_off.
+ */
+void tracing_on(void)
+{
+ ring_buffers_off = 0;
+}
+
+/**
+ * tracing_off - turn off all tracing buffers
+ *
+ * This function stops all tracing buffers from recording data.
+ * It does not disable any overhead the tracers themselves may
+ * be causing. This function simply causes all recording to
+ * the ring buffers to fail.
+ */
+void tracing_off(void)
+{
+ ring_buffers_off = 1;
+}
+
+#include "trace.h"
+
/* Up this if you want to test the TIME_EXTENTS and normalization */
#define DEBUG_SHIFT 0
@@ -154,6 +183,7 @@
struct ring_buffer_per_cpu {
int cpu;
struct ring_buffer *buffer;
+ spinlock_t reader_lock; /* serialize readers */
raw_spinlock_t lock;
struct lock_class_key lock_key;
struct list_head pages;
@@ -190,60 +220,14 @@
/* buffer may be either ring_buffer or ring_buffer_per_cpu */
#define RB_WARN_ON(buffer, cond) \
- do { \
- if (unlikely(cond)) { \
+ ({ \
+ int _____ret = unlikely(cond); \
+ if (_____ret) { \
atomic_inc(&buffer->record_disabled); \
WARN_ON(1); \
} \
- } while (0)
-
-#define RB_WARN_ON_RET(buffer, cond) \
- do { \
- if (unlikely(cond)) { \
- atomic_inc(&buffer->record_disabled); \
- WARN_ON(1); \
- return; \
- } \
- } while (0)
-
-#define RB_WARN_ON_RET_INT(buffer, cond) \
- do { \
- if (unlikely(cond)) { \
- atomic_inc(&buffer->record_disabled); \
- WARN_ON(1); \
- return -1; \
- } \
- } while (0)
-
-#define RB_WARN_ON_RET_NULL(buffer, cond) \
- do { \
- if (unlikely(cond)) { \
- atomic_inc(&buffer->record_disabled); \
- WARN_ON(1); \
- return NULL; \
- } \
- } while (0)
-
-#define RB_WARN_ON_ONCE(buffer, cond) \
- do { \
- static int once; \
- if (unlikely(cond) && !once) { \
- once++; \
- atomic_inc(&buffer->record_disabled); \
- WARN_ON(1); \
- } \
- } while (0)
-
-/* buffer must be ring_buffer not per_cpu */
-#define RB_WARN_ON_UNLOCK(buffer, cond) \
- do { \
- if (unlikely(cond)) { \
- mutex_unlock(&buffer->mutex); \
- atomic_inc(&buffer->record_disabled); \
- WARN_ON(1); \
- return -1; \
- } \
- } while (0)
+ _____ret; \
+ })
/**
* check_pages - integrity check of buffer pages
@@ -257,14 +241,18 @@
struct list_head *head = &cpu_buffer->pages;
struct buffer_page *page, *tmp;
- RB_WARN_ON_RET_INT(cpu_buffer, head->next->prev != head);
- RB_WARN_ON_RET_INT(cpu_buffer, head->prev->next != head);
+ if (RB_WARN_ON(cpu_buffer, head->next->prev != head))
+ return -1;
+ if (RB_WARN_ON(cpu_buffer, head->prev->next != head))
+ return -1;
list_for_each_entry_safe(page, tmp, head, list) {
- RB_WARN_ON_RET_INT(cpu_buffer,
- page->list.next->prev != &page->list);
- RB_WARN_ON_RET_INT(cpu_buffer,
- page->list.prev->next != &page->list);
+ if (RB_WARN_ON(cpu_buffer,
+ page->list.next->prev != &page->list))
+ return -1;
+ if (RB_WARN_ON(cpu_buffer,
+ page->list.prev->next != &page->list))
+ return -1;
}
return 0;
@@ -321,6 +309,7 @@
cpu_buffer->cpu = cpu;
cpu_buffer->buffer = buffer;
+ spin_lock_init(&cpu_buffer->reader_lock);
cpu_buffer->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
INIT_LIST_HEAD(&cpu_buffer->pages);
@@ -470,13 +459,15 @@
synchronize_sched();
for (i = 0; i < nr_pages; i++) {
- RB_WARN_ON_RET(cpu_buffer, list_empty(&cpu_buffer->pages));
+ if (RB_WARN_ON(cpu_buffer, list_empty(&cpu_buffer->pages)))
+ return;
p = cpu_buffer->pages.next;
page = list_entry(p, struct buffer_page, list);
list_del_init(&page->list);
free_buffer_page(page);
}
- RB_WARN_ON_RET(cpu_buffer, list_empty(&cpu_buffer->pages));
+ if (RB_WARN_ON(cpu_buffer, list_empty(&cpu_buffer->pages)))
+ return;
rb_reset_cpu(cpu_buffer);
@@ -498,7 +489,8 @@
synchronize_sched();
for (i = 0; i < nr_pages; i++) {
- RB_WARN_ON_RET(cpu_buffer, list_empty(pages));
+ if (RB_WARN_ON(cpu_buffer, list_empty(pages)))
+ return;
p = pages->next;
page = list_entry(p, struct buffer_page, list);
list_del_init(&page->list);
@@ -553,7 +545,10 @@
if (size < buffer_size) {
/* easy case, just free pages */
- RB_WARN_ON_UNLOCK(buffer, nr_pages >= buffer->pages);
+ if (RB_WARN_ON(buffer, nr_pages >= buffer->pages)) {
+ mutex_unlock(&buffer->mutex);
+ return -1;
+ }
rm_pages = buffer->pages - nr_pages;
@@ -572,7 +567,10 @@
* add these pages to the cpu_buffers. Otherwise we just free
* them all and return -ENOMEM;
*/
- RB_WARN_ON_UNLOCK(buffer, nr_pages <= buffer->pages);
+ if (RB_WARN_ON(buffer, nr_pages <= buffer->pages)) {
+ mutex_unlock(&buffer->mutex);
+ return -1;
+ }
new_pages = nr_pages - buffer->pages;
@@ -596,7 +594,10 @@
rb_insert_pages(cpu_buffer, &pages, new_pages);
}
- RB_WARN_ON_UNLOCK(buffer, !list_empty(&pages));
+ if (RB_WARN_ON(buffer, !list_empty(&pages))) {
+ mutex_unlock(&buffer->mutex);
+ return -1;
+ }
out:
buffer->pages = nr_pages;
@@ -684,7 +685,8 @@
head += rb_event_length(event)) {
event = __rb_page_index(cpu_buffer->head_page, head);
- RB_WARN_ON_RET(cpu_buffer, rb_null_event(event));
+ if (RB_WARN_ON(cpu_buffer, rb_null_event(event)))
+ return;
/* Only count data entries */
if (event->type != RINGBUF_TYPE_DATA)
continue;
@@ -737,8 +739,9 @@
addr &= PAGE_MASK;
while (cpu_buffer->commit_page->page != (void *)addr) {
- RB_WARN_ON(cpu_buffer,
- cpu_buffer->commit_page == cpu_buffer->tail_page);
+ if (RB_WARN_ON(cpu_buffer,
+ cpu_buffer->commit_page == cpu_buffer->tail_page))
+ return;
cpu_buffer->commit_page->commit =
cpu_buffer->commit_page->write;
rb_inc_page(cpu_buffer, &cpu_buffer->commit_page);
@@ -894,7 +897,8 @@
reader_page = cpu_buffer->reader_page;
/* we grabbed the lock before incrementing */
- RB_WARN_ON(cpu_buffer, next_page == reader_page);
+ if (RB_WARN_ON(cpu_buffer, next_page == reader_page))
+ goto out_unlock;
/*
* If for some reason, we had an interrupt storm that made
@@ -971,7 +975,8 @@
/* We reserved something on the buffer */
- RB_WARN_ON_RET_NULL(cpu_buffer, write > BUF_PAGE_SIZE);
+ if (RB_WARN_ON(cpu_buffer, write > BUF_PAGE_SIZE))
+ return NULL;
event = __rb_page_index(tail_page, tail);
rb_update_event(event, type, length);
@@ -1070,10 +1075,8 @@
* storm or we have something buggy.
* Bail!
*/
- if (unlikely(++nr_loops > 1000)) {
- RB_WARN_ON(cpu_buffer, 1);
+ if (RB_WARN_ON(cpu_buffer, ++nr_loops > 1000))
return NULL;
- }
ts = ring_buffer_time_stamp(cpu_buffer->cpu);
@@ -1169,6 +1172,9 @@
struct ring_buffer_event *event;
int cpu, resched;
+ if (ring_buffers_off)
+ return NULL;
+
if (atomic_read(&buffer->record_disabled))
return NULL;
@@ -1278,6 +1284,9 @@
int ret = -EBUSY;
int cpu, resched;
+ if (ring_buffers_off)
+ return -EBUSY;
+
if (atomic_read(&buffer->record_disabled))
return -EBUSY;
@@ -1476,6 +1485,9 @@
void ring_buffer_iter_reset(struct ring_buffer_iter *iter)
{
struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
+ unsigned long flags;
+
+ spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
/* Iterator usage is expected to have record disabled */
if (list_empty(&cpu_buffer->reader_page->list)) {
@@ -1489,6 +1501,8 @@
iter->read_stamp = cpu_buffer->read_stamp;
else
iter->read_stamp = iter->head_page->time_stamp;
+
+ spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
}
/**
@@ -1584,8 +1598,7 @@
* a case where we will loop three times. There should be no
* reason to loop four times (that I know of).
*/
- if (unlikely(++nr_loops > 3)) {
- RB_WARN_ON(cpu_buffer, 1);
+ if (RB_WARN_ON(cpu_buffer, ++nr_loops > 3)) {
reader = NULL;
goto out;
}
@@ -1597,8 +1610,9 @@
goto out;
/* Never should we have an index greater than the size */
- RB_WARN_ON(cpu_buffer,
- cpu_buffer->reader_page->read > rb_page_size(reader));
+ if (RB_WARN_ON(cpu_buffer,
+ cpu_buffer->reader_page->read > rb_page_size(reader)))
+ goto out;
/* check if we caught up to the tail */
reader = NULL;
@@ -1652,7 +1666,8 @@
reader = rb_get_reader_page(cpu_buffer);
/* This function should not be called when buffer is empty */
- RB_WARN_ON_RET(cpu_buffer, !reader);
+ if (RB_WARN_ON(cpu_buffer, !reader))
+ return;
event = rb_reader_event(cpu_buffer);
@@ -1679,8 +1694,9 @@
* Check if we are at the end of the buffer.
*/
if (iter->head >= rb_page_size(iter->head_page)) {
- RB_WARN_ON_RET(buffer,
- iter->head_page == cpu_buffer->commit_page);
+ if (RB_WARN_ON(buffer,
+ iter->head_page == cpu_buffer->commit_page))
+ return;
rb_inc_iter(iter);
return;
}
@@ -1693,9 +1709,10 @@
* This should not be called to advance the header if we are
* at the tail of the buffer.
*/
- RB_WARN_ON_RET(cpu_buffer,
+ if (RB_WARN_ON(cpu_buffer,
(iter->head_page == cpu_buffer->commit_page) &&
- (iter->head + length > rb_commit_index(cpu_buffer)));
+ (iter->head + length > rb_commit_index(cpu_buffer))))
+ return;
rb_update_iter_read_stamp(iter, event);
@@ -1707,17 +1724,8 @@
rb_advance_iter(iter);
}
-/**
- * ring_buffer_peek - peek at the next event to be read
- * @buffer: The ring buffer to read
- * @cpu: The cpu to peak at
- * @ts: The timestamp counter of this event.
- *
- * This will return the event that will be read next, but does
- * not consume the data.
- */
-struct ring_buffer_event *
-ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
+static struct ring_buffer_event *
+rb_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
{
struct ring_buffer_per_cpu *cpu_buffer;
struct ring_buffer_event *event;
@@ -1738,10 +1746,8 @@
* can have. Nesting 10 deep of interrupts is clearly
* an anomaly.
*/
- if (unlikely(++nr_loops > 10)) {
- RB_WARN_ON(cpu_buffer, 1);
+ if (RB_WARN_ON(cpu_buffer, ++nr_loops > 10))
return NULL;
- }
reader = rb_get_reader_page(cpu_buffer);
if (!reader)
@@ -1779,16 +1785,8 @@
return NULL;
}
-/**
- * ring_buffer_iter_peek - peek at the next event to be read
- * @iter: The ring buffer iterator
- * @ts: The timestamp counter of this event.
- *
- * This will return the event that will be read next, but does
- * not increment the iterator.
- */
-struct ring_buffer_event *
-ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
+static struct ring_buffer_event *
+rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
{
struct ring_buffer *buffer;
struct ring_buffer_per_cpu *cpu_buffer;
@@ -1810,10 +1808,8 @@
* can have. Nesting 10 deep of interrupts is clearly
* an anomaly.
*/
- if (unlikely(++nr_loops > 10)) {
- RB_WARN_ON(cpu_buffer, 1);
+ if (RB_WARN_ON(cpu_buffer, ++nr_loops > 10))
return NULL;
- }
if (rb_per_cpu_empty(cpu_buffer))
return NULL;
@@ -1850,6 +1846,51 @@
}
/**
+ * ring_buffer_peek - peek at the next event to be read
+ * @buffer: The ring buffer to read
+ * @cpu: The cpu to peak at
+ * @ts: The timestamp counter of this event.
+ *
+ * This will return the event that will be read next, but does
+ * not consume the data.
+ */
+struct ring_buffer_event *
+ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
+{
+ struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
+ struct ring_buffer_event *event;
+ unsigned long flags;
+
+ spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+ event = rb_buffer_peek(buffer, cpu, ts);
+ spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+
+ return event;
+}
+
+/**
+ * ring_buffer_iter_peek - peek at the next event to be read
+ * @iter: The ring buffer iterator
+ * @ts: The timestamp counter of this event.
+ *
+ * This will return the event that will be read next, but does
+ * not increment the iterator.
+ */
+struct ring_buffer_event *
+ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
+{
+ struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
+ struct ring_buffer_event *event;
+ unsigned long flags;
+
+ spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+ event = rb_iter_peek(iter, ts);
+ spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+
+ return event;
+}
+
+/**
* ring_buffer_consume - return an event and consume it
* @buffer: The ring buffer to get the next event from
*
@@ -1860,19 +1901,24 @@
struct ring_buffer_event *
ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts)
{
- struct ring_buffer_per_cpu *cpu_buffer;
+ struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
struct ring_buffer_event *event;
+ unsigned long flags;
if (!cpu_isset(cpu, buffer->cpumask))
return NULL;
- event = ring_buffer_peek(buffer, cpu, ts);
- if (!event)
- return NULL;
+ spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
- cpu_buffer = buffer->buffers[cpu];
+ event = rb_buffer_peek(buffer, cpu, ts);
+ if (!event)
+ goto out;
+
rb_advance_reader(cpu_buffer);
+ out:
+ spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+
return event;
}
@@ -1909,11 +1955,11 @@
atomic_inc(&cpu_buffer->record_disabled);
synchronize_sched();
- local_irq_save(flags);
+ spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
__raw_spin_lock(&cpu_buffer->lock);
ring_buffer_iter_reset(iter);
__raw_spin_unlock(&cpu_buffer->lock);
- local_irq_restore(flags);
+ spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
return iter;
}
@@ -1945,12 +1991,17 @@
ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts)
{
struct ring_buffer_event *event;
+ struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
+ unsigned long flags;
- event = ring_buffer_iter_peek(iter, ts);
+ spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+ event = rb_iter_peek(iter, ts);
if (!event)
- return NULL;
+ goto out;
rb_advance_iter(iter);
+ out:
+ spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
return event;
}
@@ -1999,13 +2050,15 @@
if (!cpu_isset(cpu, buffer->cpumask))
return;
- local_irq_save(flags);
+ spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+
__raw_spin_lock(&cpu_buffer->lock);
rb_reset_cpu(cpu_buffer);
__raw_spin_unlock(&cpu_buffer->lock);
- local_irq_restore(flags);
+
+ spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
}
/**
@@ -2103,3 +2156,69 @@
return 0;
}
+static ssize_t
+rb_simple_read(struct file *filp, char __user *ubuf,
+ size_t cnt, loff_t *ppos)
+{
+ int *p = filp->private_data;
+ char buf[64];
+ int r;
+
+ /* !ring_buffers_off == tracing_on */
+ r = sprintf(buf, "%d\n", !*p);
+
+ return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+rb_simple_write(struct file *filp, const char __user *ubuf,
+ size_t cnt, loff_t *ppos)
+{
+ int *p = filp->private_data;
+ char buf[64];
+ long val;
+ int ret;
+
+ if (cnt >= sizeof(buf))
+ return -EINVAL;
+
+ if (copy_from_user(&buf, ubuf, cnt))
+ return -EFAULT;
+
+ buf[cnt] = 0;
+
+ ret = strict_strtoul(buf, 10, &val);
+ if (ret < 0)
+ return ret;
+
+ /* !ring_buffers_off == tracing_on */
+ *p = !val;
+
+ (*ppos)++;
+
+ return cnt;
+}
+
+static struct file_operations rb_simple_fops = {
+ .open = tracing_open_generic,
+ .read = rb_simple_read,
+ .write = rb_simple_write,
+};
+
+
+static __init int rb_init_debugfs(void)
+{
+ struct dentry *d_tracer;
+ struct dentry *entry;
+
+ d_tracer = tracing_init_dentry();
+
+ entry = debugfs_create_file("tracing_on", 0644, d_tracer,
+ &ring_buffers_off, &rb_simple_fops);
+ if (!entry)
+ pr_warning("Could not create debugfs 'tracing_on' entry\n");
+
+ return 0;
+}
+
+fs_initcall(rb_init_debugfs);