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-rw-r--r--include/linux/ring_buffer.h3
-rw-r--r--kernel/trace/ring_buffer.c298
-rw-r--r--kernel/trace/trace.c113
3 files changed, 247 insertions, 167 deletions
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index c52375b8330d..536b0ca46a03 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -63,9 +63,6 @@ ring_buffer_event_time_delta(struct ring_buffer_event *event)
return event->time_delta;
}
-void ring_buffer_lock(struct ring_buffer *buffer, unsigned long *flags);
-void ring_buffer_unlock(struct ring_buffer *buffer, unsigned long flags);
-
/*
* size is in bytes for each per CPU buffer.
*/
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 8e7392fd0db9..9631abf2ae29 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -161,8 +161,10 @@ struct ring_buffer_per_cpu {
struct list_head pages;
unsigned long head; /* read from head */
unsigned long tail; /* write to tail */
+ unsigned long reader;
struct buffer_page *head_page;
struct buffer_page *tail_page;
+ struct buffer_page *reader_page;
unsigned long overrun;
unsigned long entries;
u64 write_stamp;
@@ -260,6 +262,7 @@ static struct ring_buffer_per_cpu *
rb_allocate_cpu_buffer(struct ring_buffer *buffer, int cpu)
{
struct ring_buffer_per_cpu *cpu_buffer;
+ unsigned long addr;
int ret;
cpu_buffer = kzalloc_node(ALIGN(sizeof(*cpu_buffer), cache_line_size()),
@@ -272,9 +275,16 @@ rb_allocate_cpu_buffer(struct ring_buffer *buffer, int cpu)
spin_lock_init(&cpu_buffer->lock);
INIT_LIST_HEAD(&cpu_buffer->pages);
+ addr = __get_free_page(GFP_KERNEL);
+ if (!addr)
+ goto fail_free_buffer;
+ cpu_buffer->reader_page = (struct buffer_page *)virt_to_page(addr);
+ INIT_LIST_HEAD(&cpu_buffer->reader_page->list);
+ cpu_buffer->reader_page->size = 0;
+
ret = rb_allocate_pages(cpu_buffer, buffer->pages);
if (ret < 0)
- goto fail_free_buffer;
+ goto fail_free_reader;
cpu_buffer->head_page
= list_entry(cpu_buffer->pages.next, struct buffer_page, list);
@@ -283,6 +293,9 @@ rb_allocate_cpu_buffer(struct ring_buffer *buffer, int cpu)
return cpu_buffer;
+ fail_free_reader:
+ free_buffer_page(cpu_buffer->reader_page);
+
fail_free_buffer:
kfree(cpu_buffer);
return NULL;
@@ -293,6 +306,9 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
struct list_head *head = &cpu_buffer->pages;
struct buffer_page *page, *tmp;
+ list_del_init(&cpu_buffer->reader_page->list);
+ free_buffer_page(cpu_buffer->reader_page);
+
list_for_each_entry_safe(page, tmp, head, list) {
list_del_init(&page->list);
free_buffer_page(page);
@@ -538,8 +554,10 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
static inline int rb_per_cpu_empty(struct ring_buffer_per_cpu *cpu_buffer)
{
- return cpu_buffer->head_page == cpu_buffer->tail_page &&
- cpu_buffer->head == cpu_buffer->tail;
+ return (cpu_buffer->reader == cpu_buffer->reader_page->size &&
+ (cpu_buffer->tail_page == cpu_buffer->reader_page ||
+ (cpu_buffer->tail_page == cpu_buffer->head_page &&
+ cpu_buffer->head == cpu_buffer->tail)));
}
static inline int rb_null_event(struct ring_buffer_event *event)
@@ -555,10 +573,10 @@ static inline void *rb_page_index(struct buffer_page *page, unsigned index)
}
static inline struct ring_buffer_event *
-rb_head_event(struct ring_buffer_per_cpu *cpu_buffer)
+rb_reader_event(struct ring_buffer_per_cpu *cpu_buffer)
{
- return rb_page_index(cpu_buffer->head_page,
- cpu_buffer->head);
+ return rb_page_index(cpu_buffer->reader_page,
+ cpu_buffer->reader);
}
static inline struct ring_buffer_event *
@@ -610,15 +628,32 @@ rb_add_stamp(struct ring_buffer_per_cpu *cpu_buffer, u64 *ts)
cpu_buffer->write_stamp = *ts;
}
-static void rb_reset_read_page(struct ring_buffer_per_cpu *cpu_buffer)
+static void rb_reset_head_page(struct ring_buffer_per_cpu *cpu_buffer)
{
- cpu_buffer->read_stamp = cpu_buffer->head_page->time_stamp;
cpu_buffer->head = 0;
}
-static void
-rb_reset_iter_read_page(struct ring_buffer_iter *iter)
+static void rb_reset_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
{
+ cpu_buffer->read_stamp = cpu_buffer->reader_page->time_stamp;
+ cpu_buffer->reader = 0;
+}
+
+static inline void rb_inc_iter(struct ring_buffer_iter *iter)
+{
+ struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
+
+ /*
+ * The iterator could be on the reader page (it starts there).
+ * But the head could have moved, since the reader was
+ * found. Check for this case and assign the iterator
+ * to the head page instead of next.
+ */
+ if (iter->head_page == cpu_buffer->reader_page)
+ iter->head_page = cpu_buffer->head_page;
+ else
+ rb_inc_page(cpu_buffer, &iter->head_page);
+
iter->read_stamp = iter->head_page->time_stamp;
iter->head = 0;
}
@@ -693,30 +728,39 @@ static struct ring_buffer_event *
__rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
unsigned type, unsigned long length, u64 *ts)
{
- struct buffer_page *head_page, *tail_page;
+ struct buffer_page *tail_page, *head_page, *reader_page;
unsigned long tail;
struct ring_buffer *buffer = cpu_buffer->buffer;
struct ring_buffer_event *event;
+ /* No locking needed for tail page */
tail_page = cpu_buffer->tail_page;
- head_page = cpu_buffer->head_page;
tail = cpu_buffer->tail;
if (tail + length > BUF_PAGE_SIZE) {
struct buffer_page *next_page = tail_page;
+ spin_lock(&cpu_buffer->lock);
rb_inc_page(cpu_buffer, &next_page);
+ head_page = cpu_buffer->head_page;
+ reader_page = cpu_buffer->reader_page;
+
+ /* we grabbed the lock before incrementing */
+ WARN_ON(next_page == reader_page);
+
if (next_page == head_page) {
- if (!(buffer->flags & RB_FL_OVERWRITE))
+ if (!(buffer->flags & RB_FL_OVERWRITE)) {
+ spin_unlock(&cpu_buffer->lock);
return NULL;
+ }
/* count overflows */
rb_update_overflow(cpu_buffer);
rb_inc_page(cpu_buffer, &head_page);
cpu_buffer->head_page = head_page;
- rb_reset_read_page(cpu_buffer);
+ rb_reset_head_page(cpu_buffer);
}
if (tail != BUF_PAGE_SIZE) {
@@ -732,6 +776,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
cpu_buffer->tail_page = tail_page;
cpu_buffer->tail = tail;
rb_add_stamp(cpu_buffer, ts);
+ spin_unlock(&cpu_buffer->lock);
}
BUG_ON(tail + length > BUF_PAGE_SIZE);
@@ -802,7 +847,9 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
return NULL;
}
} else {
+ spin_lock(&cpu_buffer->lock);
rb_add_stamp(cpu_buffer, &ts);
+ spin_unlock(&cpu_buffer->lock);
delta = 0;
}
@@ -851,13 +898,12 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer,
cpu = raw_smp_processor_id();
if (!cpu_isset(cpu, buffer->cpumask))
- goto out_irq;
+ goto out;
cpu_buffer = buffer->buffers[cpu];
- spin_lock(&cpu_buffer->lock);
if (atomic_read(&cpu_buffer->record_disabled))
- goto no_record;
+ goto out;
length = rb_calculate_event_length(length);
if (length > BUF_PAGE_SIZE)
@@ -865,13 +911,11 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer,
event = rb_reserve_next_event(cpu_buffer, RINGBUF_TYPE_DATA, length);
if (!event)
- goto no_record;
+ goto out;
return event;
- no_record:
- spin_unlock(&cpu_buffer->lock);
- out_irq:
+ out:
local_irq_restore(*flags);
return NULL;
}
@@ -904,11 +948,8 @@ int ring_buffer_unlock_commit(struct ring_buffer *buffer,
cpu_buffer = buffer->buffers[cpu];
- assert_spin_locked(&cpu_buffer->lock);
-
rb_commit(cpu_buffer, event);
- spin_unlock(&cpu_buffer->lock);
local_irq_restore(flags);
return 0;
@@ -945,10 +986,9 @@ int ring_buffer_write(struct ring_buffer *buffer,
cpu = raw_smp_processor_id();
if (!cpu_isset(cpu, buffer->cpumask))
- goto out_irq;
+ goto out;
cpu_buffer = buffer->buffers[cpu];
- spin_lock(&cpu_buffer->lock);
if (atomic_read(&cpu_buffer->record_disabled))
goto out;
@@ -967,56 +1007,12 @@ int ring_buffer_write(struct ring_buffer *buffer,
ret = 0;
out:
- spin_unlock(&cpu_buffer->lock);
- out_irq:
local_irq_restore(flags);
return ret;
}
/**
- * ring_buffer_lock - lock the ring buffer
- * @buffer: The ring buffer to lock
- * @flags: The place to store the interrupt flags
- *
- * This locks all the per CPU buffers.
- *
- * Must be unlocked by ring_buffer_unlock.
- */
-void ring_buffer_lock(struct ring_buffer *buffer, unsigned long *flags)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- int cpu;
-
- local_irq_save(*flags);
-
- for_each_buffer_cpu(buffer, cpu) {
- cpu_buffer = buffer->buffers[cpu];
- spin_lock(&cpu_buffer->lock);
- }
-}
-
-/**
- * ring_buffer_unlock - unlock a locked buffer
- * @buffer: The locked buffer to unlock
- * @flags: The interrupt flags received by ring_buffer_lock
- */
-void ring_buffer_unlock(struct ring_buffer *buffer, unsigned long flags)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- int cpu;
-
- for (cpu = buffer->cpus - 1; cpu >= 0; cpu--) {
- if (!cpu_isset(cpu, buffer->cpumask))
- continue;
- cpu_buffer = buffer->buffers[cpu];
- spin_unlock(&cpu_buffer->lock);
- }
-
- local_irq_restore(flags);
-}
-
-/**
* ring_buffer_record_disable - stop all writes into the buffer
* @buffer: The ring buffer to stop writes to.
*
@@ -1169,9 +1165,18 @@ void ring_buffer_iter_reset(struct ring_buffer_iter *iter)
{
struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
- iter->head_page = cpu_buffer->head_page;
- iter->head = cpu_buffer->head;
- rb_reset_iter_read_page(iter);
+ /* Iterator usage is expected to have record disabled */
+ if (list_empty(&cpu_buffer->reader_page->list)) {
+ iter->head_page = cpu_buffer->head_page;
+ iter->head = cpu_buffer->head;
+ } else {
+ iter->head_page = cpu_buffer->reader_page;
+ iter->head = cpu_buffer->reader;
+ }
+ if (iter->head)
+ iter->read_stamp = cpu_buffer->read_stamp;
+ else
+ iter->read_stamp = iter->head_page->time_stamp;
}
/**
@@ -1250,43 +1255,84 @@ rb_update_iter_read_stamp(struct ring_buffer_iter *iter,
return;
}
-static void rb_advance_head(struct ring_buffer_per_cpu *cpu_buffer)
+static struct buffer_page *
+rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
{
- struct ring_buffer_event *event;
- unsigned length;
+ struct buffer_page *reader = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&cpu_buffer->lock, flags);
+
+ again:
+ reader = cpu_buffer->reader_page;
+
+ /* If there's more to read, return this page */
+ if (cpu_buffer->reader < reader->size)
+ goto out;
+
+ /* Never should we have an index greater than the size */
+ WARN_ON(cpu_buffer->reader > reader->size);
+
+ /* check if we caught up to the tail */
+ reader = NULL;
+ if (cpu_buffer->tail_page == cpu_buffer->reader_page)
+ goto out;
/*
- * Check if we are at the end of the buffer.
+ * Splice the empty reader page into the list around the head.
+ * Reset the reader page to size zero.
*/
- if (cpu_buffer->head >= cpu_buffer->head_page->size) {
- BUG_ON(cpu_buffer->head_page == cpu_buffer->tail_page);
- rb_inc_page(cpu_buffer, &cpu_buffer->head_page);
- rb_reset_read_page(cpu_buffer);
- return;
- }
- event = rb_head_event(cpu_buffer);
+ reader = cpu_buffer->head_page;
+ cpu_buffer->reader_page->list.next = reader->list.next;
+ cpu_buffer->reader_page->list.prev = reader->list.prev;
+ cpu_buffer->reader_page->size = 0;
- if (event->type == RINGBUF_TYPE_DATA)
- cpu_buffer->entries--;
-
- length = rb_event_length(event);
+ /* Make the reader page now replace the head */
+ reader->list.prev->next = &cpu_buffer->reader_page->list;
+ reader->list.next->prev = &cpu_buffer->reader_page->list;
/*
- * This should not be called to advance the header if we are
- * at the tail of the buffer.
+ * If the tail is on the reader, then we must set the head
+ * to the inserted page, otherwise we set it one before.
*/
- BUG_ON((cpu_buffer->head_page == cpu_buffer->tail_page) &&
- (cpu_buffer->head + length > cpu_buffer->tail));
+ cpu_buffer->head_page = cpu_buffer->reader_page;
- rb_update_read_stamp(cpu_buffer, event);
+ if (cpu_buffer->tail_page != reader)
+ rb_inc_page(cpu_buffer, &cpu_buffer->head_page);
+
+ /* Finally update the reader page to the new head */
+ cpu_buffer->reader_page = reader;
+ rb_reset_reader_page(cpu_buffer);
+
+ goto again;
+
+ out:
+ spin_unlock_irqrestore(&cpu_buffer->lock, flags);
+
+ return reader;
+}
+
+static void rb_advance_reader(struct ring_buffer_per_cpu *cpu_buffer)
+{
+ struct ring_buffer_event *event;
+ struct buffer_page *reader;
+ unsigned length;
+
+ reader = rb_get_reader_page(cpu_buffer);
- cpu_buffer->head += length;
+ /* This function should not be called when buffer is empty */
+ BUG_ON(!reader);
- /* check for end of page */
- if ((cpu_buffer->head >= cpu_buffer->head_page->size) &&
- (cpu_buffer->head_page != cpu_buffer->tail_page))
- rb_advance_head(cpu_buffer);
+ event = rb_reader_event(cpu_buffer);
+
+ if (event->type == RINGBUF_TYPE_DATA)
+ cpu_buffer->entries--;
+
+ rb_update_read_stamp(cpu_buffer, event);
+
+ length = rb_event_length(event);
+ cpu_buffer->reader += length;
}
static void rb_advance_iter(struct ring_buffer_iter *iter)
@@ -1304,8 +1350,7 @@ static void rb_advance_iter(struct ring_buffer_iter *iter)
*/
if (iter->head >= iter->head_page->size) {
BUG_ON(iter->head_page == cpu_buffer->tail_page);
- rb_inc_page(cpu_buffer, &iter->head_page);
- rb_reset_iter_read_page(iter);
+ rb_inc_iter(iter);
return;
}
@@ -1344,6 +1389,7 @@ ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
{
struct ring_buffer_per_cpu *cpu_buffer;
struct ring_buffer_event *event;
+ struct buffer_page *reader;
if (!cpu_isset(cpu, buffer->cpumask))
return NULL;
@@ -1351,25 +1397,26 @@ ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
cpu_buffer = buffer->buffers[cpu];
again:
- if (rb_per_cpu_empty(cpu_buffer))
+ reader = rb_get_reader_page(cpu_buffer);
+ if (!reader)
return NULL;
- event = rb_head_event(cpu_buffer);
+ event = rb_reader_event(cpu_buffer);
switch (event->type) {
case RINGBUF_TYPE_PADDING:
- rb_inc_page(cpu_buffer, &cpu_buffer->head_page);
- rb_reset_read_page(cpu_buffer);
- goto again;
+ WARN_ON(1);
+ rb_advance_reader(cpu_buffer);
+ return NULL;
case RINGBUF_TYPE_TIME_EXTEND:
/* Internal data, OK to advance */
- rb_advance_head(cpu_buffer);
+ rb_advance_reader(cpu_buffer);
goto again;
case RINGBUF_TYPE_TIME_STAMP:
/* FIXME: not implemented */
- rb_advance_head(cpu_buffer);
+ rb_advance_reader(cpu_buffer);
goto again;
case RINGBUF_TYPE_DATA:
@@ -1415,8 +1462,7 @@ ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
switch (event->type) {
case RINGBUF_TYPE_PADDING:
- rb_inc_page(cpu_buffer, &iter->head_page);
- rb_reset_iter_read_page(iter);
+ rb_inc_iter(iter);
goto again;
case RINGBUF_TYPE_TIME_EXTEND:
@@ -1465,7 +1511,7 @@ ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts)
return NULL;
cpu_buffer = buffer->buffers[cpu];
- rb_advance_head(cpu_buffer);
+ rb_advance_reader(cpu_buffer);
return event;
}
@@ -1487,6 +1533,7 @@ ring_buffer_read_start(struct ring_buffer *buffer, int cpu)
{
struct ring_buffer_per_cpu *cpu_buffer;
struct ring_buffer_iter *iter;
+ unsigned long flags;
if (!cpu_isset(cpu, buffer->cpumask))
return NULL;
@@ -1502,11 +1549,9 @@ ring_buffer_read_start(struct ring_buffer *buffer, int cpu)
atomic_inc(&cpu_buffer->record_disabled);
synchronize_sched();
- spin_lock(&cpu_buffer->lock);
- iter->head = cpu_buffer->head;
- iter->head_page = cpu_buffer->head_page;
- rb_reset_iter_read_page(iter);
- spin_unlock(&cpu_buffer->lock);
+ spin_lock_irqsave(&cpu_buffer->lock, flags);
+ ring_buffer_iter_reset(iter);
+ spin_unlock_irqrestore(&cpu_buffer->lock, flags);
return iter;
}
@@ -1562,10 +1607,14 @@ rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer)
{
cpu_buffer->head_page
= list_entry(cpu_buffer->pages.next, struct buffer_page, list);
- cpu_buffer->tail_page
- = list_entry(cpu_buffer->pages.next, struct buffer_page, list);
+ cpu_buffer->head_page->size = 0;
+ cpu_buffer->tail_page = cpu_buffer->head_page;
+ cpu_buffer->tail_page->size = 0;
+ INIT_LIST_HEAD(&cpu_buffer->reader_page->list);
+ cpu_buffer->reader_page->size = 0;
+
+ cpu_buffer->head = cpu_buffer->tail = cpu_buffer->reader = 0;
- cpu_buffer->head = cpu_buffer->tail = 0;
cpu_buffer->overrun = 0;
cpu_buffer->entries = 0;
}
@@ -1583,13 +1632,11 @@ void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu)
if (!cpu_isset(cpu, buffer->cpumask))
return;
- local_irq_save(flags);
- spin_lock(&cpu_buffer->lock);
+ spin_lock_irqsave(&cpu_buffer->lock, flags);
rb_reset_cpu(cpu_buffer);
- spin_unlock(&cpu_buffer->lock);
- local_irq_restore(flags);
+ spin_unlock_irqrestore(&cpu_buffer->lock, flags);
}
/**
@@ -1598,15 +1645,10 @@ void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu)
*/
void ring_buffer_reset(struct ring_buffer *buffer)
{
- unsigned long flags;
int cpu;
- ring_buffer_lock(buffer, &flags);
-
for_each_buffer_cpu(buffer, cpu)
- rb_reset_cpu(buffer->buffers[cpu]);
-
- ring_buffer_unlock(buffer, flags);
+ ring_buffer_reset_cpu(buffer, cpu);
}
/**
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 6a1c76bb56ba..b542f8837801 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -42,6 +42,20 @@
unsigned long __read_mostly tracing_max_latency = (cycle_t)ULONG_MAX;
unsigned long __read_mostly tracing_thresh;
+static DEFINE_PER_CPU(local_t, ftrace_cpu_disabled);
+
+static inline void ftrace_disable_cpu(void)
+{
+ preempt_disable();
+ local_inc(&__get_cpu_var(ftrace_cpu_disabled));
+}
+
+static inline void ftrace_enable_cpu(void)
+{
+ local_dec(&__get_cpu_var(ftrace_cpu_disabled));
+ preempt_enable();
+}
+
static cpumask_t __read_mostly tracing_buffer_mask;
#define for_each_tracing_cpu(cpu) \
@@ -406,7 +420,9 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
tr->buffer = max_tr.buffer;
max_tr.buffer = buf;
+ ftrace_disable_cpu();
ring_buffer_reset(tr->buffer);
+ ftrace_enable_cpu();
__update_max_tr(tr, tsk, cpu);
__raw_spin_unlock(&ftrace_max_lock);
@@ -428,9 +444,13 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
WARN_ON_ONCE(!irqs_disabled());
__raw_spin_lock(&ftrace_max_lock);
+ ftrace_disable_cpu();
+
ring_buffer_reset(max_tr.buffer);
ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
+ ftrace_enable_cpu();
+
WARN_ON_ONCE(ret);
__update_max_tr(tr, tsk, cpu);
@@ -543,7 +563,9 @@ void unregister_tracer(struct tracer *type)
void tracing_reset(struct trace_array *tr, int cpu)
{
+ ftrace_disable_cpu();
ring_buffer_reset_cpu(tr->buffer, cpu);
+ ftrace_enable_cpu();
}
#define SAVED_CMDLINES 128
@@ -654,6 +676,10 @@ trace_function(struct trace_array *tr, struct trace_array_cpu *data,
struct ftrace_entry *entry;
unsigned long irq_flags;
+ /* If we are reading the ring buffer, don't trace */
+ if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
+ return;
+
event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
&irq_flags);
if (!event)
@@ -870,8 +896,14 @@ enum trace_file_type {
static void trace_iterator_increment(struct trace_iterator *iter, int cpu)
{
+ /* Don't allow ftrace to trace into the ring buffers */
+ ftrace_disable_cpu();
+
iter->idx++;
- ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
+ if (iter->buffer_iter[iter->cpu])
+ ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
+
+ ftrace_enable_cpu();
}
static struct trace_entry *
@@ -880,9 +912,19 @@ peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts)
struct ring_buffer_event *event;
struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
- event = ring_buffer_iter_peek(buf_iter, ts);
+ /* Don't allow ftrace to trace into the ring buffers */
+ ftrace_disable_cpu();
+
+ if (buf_iter)
+ event = ring_buffer_iter_peek(buf_iter, ts);
+ else
+ event = ring_buffer_peek(iter->tr->buffer, cpu, ts);
+
+ ftrace_enable_cpu();
+
return event ? ring_buffer_event_data(event) : NULL;
}
+
static struct trace_entry *
__find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts)
{
@@ -938,7 +980,10 @@ static void *find_next_entry_inc(struct trace_iterator *iter)
static void trace_consume(struct trace_iterator *iter)
{
+ /* Don't allow ftrace to trace into the ring buffers */
+ ftrace_disable_cpu();
ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts);
+ ftrace_enable_cpu();
}
static void *s_next(struct seq_file *m, void *v, loff_t *pos)
@@ -991,10 +1036,14 @@ static void *s_start(struct seq_file *m, loff_t *pos)
iter->cpu = 0;
iter->idx = -1;
+ ftrace_disable_cpu();
+
for_each_tracing_cpu(cpu) {
ring_buffer_iter_reset(iter->buffer_iter[cpu]);
}
+ ftrace_enable_cpu();
+
for (p = iter; p && l < *pos; p = s_next(m, p, &l))
;
@@ -1242,7 +1291,16 @@ void trace_seq_print_cont(struct trace_seq *s, struct trace_iterator *iter)
cont = (struct trace_field_cont *)ent;
if (ok)
ok = (trace_seq_printf(s, "%s", cont->buf) > 0);
- ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
+
+ ftrace_disable_cpu();
+
+ if (iter->buffer_iter[iter->cpu])
+ ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
+ else
+ ring_buffer_consume(iter->tr->buffer, iter->cpu, NULL);
+
+ ftrace_enable_cpu();
+
ent = peek_next_entry(iter, iter->cpu, NULL);
} while (ent && ent->type == TRACE_CONT);
@@ -1683,9 +1741,15 @@ static int trace_empty(struct trace_iterator *iter)
int cpu;
for_each_tracing_cpu(cpu) {
- if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
- return 0;
+ if (iter->buffer_iter[cpu]) {
+ if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
+ return 0;
+ } else {
+ if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
+ return 0;
+ }
}
+
return TRACE_TYPE_HANDLED;
}
@@ -1776,8 +1840,10 @@ __tracing_open(struct inode *inode, struct file *file, int *ret)
iter->pos = -1;
for_each_tracing_cpu(cpu) {
+
iter->buffer_iter[cpu] =
ring_buffer_read_start(iter->tr->buffer, cpu);
+
if (!iter->buffer_iter[cpu])
goto fail_buffer;
}
@@ -2341,7 +2407,6 @@ static atomic_t tracing_reader;
static int tracing_open_pipe(struct inode *inode, struct file *filp)
{
struct trace_iterator *iter;
- int cpu;
if (tracing_disabled)
return -ENODEV;
@@ -2362,38 +2427,17 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
iter->trace = current_trace;
filp->private_data = iter;
- for_each_tracing_cpu(cpu) {
- iter->buffer_iter[cpu] =
- ring_buffer_read_start(iter->tr->buffer, cpu);
- if (!iter->buffer_iter[cpu])
- goto fail_buffer;
- }
-
if (iter->trace->pipe_open)
iter->trace->pipe_open(iter);
mutex_unlock(&trace_types_lock);
return 0;
-
- fail_buffer:
- for_each_tracing_cpu(cpu) {
- if (iter->buffer_iter[cpu])
- ring_buffer_read_finish(iter->buffer_iter[cpu]);
- }
- mutex_unlock(&trace_types_lock);
-
- return -ENOMEM;
}
static int tracing_release_pipe(struct inode *inode, struct file *file)
{
struct trace_iterator *iter = file->private_data;
- int cpu;
- for_each_tracing_cpu(cpu) {
- if (iter->buffer_iter[cpu])
- ring_buffer_read_finish(iter->buffer_iter[cpu]);
- }
kfree(iter);
atomic_dec(&tracing_reader);
@@ -2429,7 +2473,6 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct trace_iterator *iter = filp->private_data;
- unsigned long flags;
#ifdef CONFIG_FTRACE
int ftrace_save;
#endif
@@ -2528,7 +2571,6 @@ waitagain:
ftrace_enabled = 0;
#endif
smp_wmb();
- ring_buffer_lock(iter->tr->buffer, &flags);
while (find_next_entry_inc(iter) != NULL) {
enum print_line_t ret;
@@ -2547,7 +2589,6 @@ waitagain:
break;
}
- ring_buffer_unlock(iter->tr->buffer, flags);
#ifdef CONFIG_FTRACE
ftrace_enabled = ftrace_save;
#endif
@@ -3010,8 +3051,8 @@ void ftrace_dump(void)
static struct trace_iterator iter;
static cpumask_t mask;
static int dump_ran;
- unsigned long flags, irq_flags;
- int cnt = 0;
+ unsigned long flags;
+ int cnt = 0, cpu;
/* only one dump */
spin_lock_irqsave(&ftrace_dump_lock, flags);
@@ -3023,6 +3064,10 @@ void ftrace_dump(void)
/* No turning back! */
ftrace_kill_atomic();
+ for_each_tracing_cpu(cpu) {
+ atomic_inc(&global_trace.data[cpu]->disabled);
+ }
+
printk(KERN_TRACE "Dumping ftrace buffer:\n");
iter.tr = &global_trace;
@@ -3037,8 +3082,6 @@ void ftrace_dump(void)
cpus_clear(mask);
- ring_buffer_lock(iter.tr->buffer, &irq_flags);
-
while (!trace_empty(&iter)) {
if (!cnt)
@@ -3066,8 +3109,6 @@ void ftrace_dump(void)
else
printk(KERN_TRACE "---------------------------------\n");
- ring_buffer_unlock(iter.tr->buffer, irq_flags);
-
out:
spin_unlock_irqrestore(&ftrace_dump_lock, flags);
}