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-rw-r--r--kernel/trace/ring_buffer.c154
1 files changed, 89 insertions, 65 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 2d75c94ae87d..7a4104cb95cb 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -34,21 +34,19 @@ static void update_pages_handler(struct work_struct *work);
*/
int ring_buffer_print_entry_header(struct trace_seq *s)
{
- int ret;
-
- ret = trace_seq_puts(s, "# compressed entry header\n");
- ret = trace_seq_puts(s, "\ttype_len : 5 bits\n");
- ret = trace_seq_puts(s, "\ttime_delta : 27 bits\n");
- ret = trace_seq_puts(s, "\tarray : 32 bits\n");
- ret = trace_seq_putc(s, '\n');
- ret = trace_seq_printf(s, "\tpadding : type == %d\n",
- RINGBUF_TYPE_PADDING);
- ret = trace_seq_printf(s, "\ttime_extend : type == %d\n",
- RINGBUF_TYPE_TIME_EXTEND);
- ret = trace_seq_printf(s, "\tdata max type_len == %d\n",
- RINGBUF_TYPE_DATA_TYPE_LEN_MAX);
+ trace_seq_puts(s, "# compressed entry header\n");
+ trace_seq_puts(s, "\ttype_len : 5 bits\n");
+ trace_seq_puts(s, "\ttime_delta : 27 bits\n");
+ trace_seq_puts(s, "\tarray : 32 bits\n");
+ trace_seq_putc(s, '\n');
+ trace_seq_printf(s, "\tpadding : type == %d\n",
+ RINGBUF_TYPE_PADDING);
+ trace_seq_printf(s, "\ttime_extend : type == %d\n",
+ RINGBUF_TYPE_TIME_EXTEND);
+ trace_seq_printf(s, "\tdata max type_len == %d\n",
+ RINGBUF_TYPE_DATA_TYPE_LEN_MAX);
- return ret;
+ return !trace_seq_has_overflowed(s);
}
/*
@@ -419,32 +417,31 @@ static inline int test_time_stamp(u64 delta)
int ring_buffer_print_page_header(struct trace_seq *s)
{
struct buffer_data_page field;
- int ret;
- ret = trace_seq_printf(s, "\tfield: u64 timestamp;\t"
- "offset:0;\tsize:%u;\tsigned:%u;\n",
- (unsigned int)sizeof(field.time_stamp),
- (unsigned int)is_signed_type(u64));
-
- ret = trace_seq_printf(s, "\tfield: local_t commit;\t"
- "offset:%u;\tsize:%u;\tsigned:%u;\n",
- (unsigned int)offsetof(typeof(field), commit),
- (unsigned int)sizeof(field.commit),
- (unsigned int)is_signed_type(long));
-
- ret = trace_seq_printf(s, "\tfield: int overwrite;\t"
- "offset:%u;\tsize:%u;\tsigned:%u;\n",
- (unsigned int)offsetof(typeof(field), commit),
- 1,
- (unsigned int)is_signed_type(long));
-
- ret = trace_seq_printf(s, "\tfield: char data;\t"
- "offset:%u;\tsize:%u;\tsigned:%u;\n",
- (unsigned int)offsetof(typeof(field), data),
- (unsigned int)BUF_PAGE_SIZE,
- (unsigned int)is_signed_type(char));
+ trace_seq_printf(s, "\tfield: u64 timestamp;\t"
+ "offset:0;\tsize:%u;\tsigned:%u;\n",
+ (unsigned int)sizeof(field.time_stamp),
+ (unsigned int)is_signed_type(u64));
- return ret;
+ trace_seq_printf(s, "\tfield: local_t commit;\t"
+ "offset:%u;\tsize:%u;\tsigned:%u;\n",
+ (unsigned int)offsetof(typeof(field), commit),
+ (unsigned int)sizeof(field.commit),
+ (unsigned int)is_signed_type(long));
+
+ trace_seq_printf(s, "\tfield: int overwrite;\t"
+ "offset:%u;\tsize:%u;\tsigned:%u;\n",
+ (unsigned int)offsetof(typeof(field), commit),
+ 1,
+ (unsigned int)is_signed_type(long));
+
+ trace_seq_printf(s, "\tfield: char data;\t"
+ "offset:%u;\tsize:%u;\tsigned:%u;\n",
+ (unsigned int)offsetof(typeof(field), data),
+ (unsigned int)BUF_PAGE_SIZE,
+ (unsigned int)is_signed_type(char));
+
+ return !trace_seq_has_overflowed(s);
}
struct rb_irq_work {
@@ -538,16 +535,18 @@ static void rb_wake_up_waiters(struct irq_work *work)
* ring_buffer_wait - wait for input to the ring buffer
* @buffer: buffer to wait on
* @cpu: the cpu buffer to wait on
+ * @full: wait until a full page is available, if @cpu != RING_BUFFER_ALL_CPUS
*
* If @cpu == RING_BUFFER_ALL_CPUS then the task will wake up as soon
* as data is added to any of the @buffer's cpu buffers. Otherwise
* it will wait for data to be added to a specific cpu buffer.
*/
-int ring_buffer_wait(struct ring_buffer *buffer, int cpu)
+int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool full)
{
- struct ring_buffer_per_cpu *cpu_buffer;
+ struct ring_buffer_per_cpu *uninitialized_var(cpu_buffer);
DEFINE_WAIT(wait);
struct rb_irq_work *work;
+ int ret = 0;
/*
* Depending on what the caller is waiting for, either any
@@ -564,36 +563,61 @@ int ring_buffer_wait(struct ring_buffer *buffer, int cpu)
}
- prepare_to_wait(&work->waiters, &wait, TASK_INTERRUPTIBLE);
+ while (true) {
+ prepare_to_wait(&work->waiters, &wait, TASK_INTERRUPTIBLE);
- /*
- * The events can happen in critical sections where
- * checking a work queue can cause deadlocks.
- * After adding a task to the queue, this flag is set
- * only to notify events to try to wake up the queue
- * using irq_work.
- *
- * We don't clear it even if the buffer is no longer
- * empty. The flag only causes the next event to run
- * irq_work to do the work queue wake up. The worse
- * that can happen if we race with !trace_empty() is that
- * an event will cause an irq_work to try to wake up
- * an empty queue.
- *
- * There's no reason to protect this flag either, as
- * the work queue and irq_work logic will do the necessary
- * synchronization for the wake ups. The only thing
- * 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;
+ /*
+ * The events can happen in critical sections where
+ * checking a work queue can cause deadlocks.
+ * After adding a task to the queue, this flag is set
+ * only to notify events to try to wake up the queue
+ * using irq_work.
+ *
+ * We don't clear it even if the buffer is no longer
+ * empty. The flag only causes the next event to run
+ * irq_work to do the work queue wake up. The worse
+ * that can happen if we race with !trace_empty() is that
+ * an event will cause an irq_work to try to wake up
+ * an empty queue.
+ *
+ * There's no reason to protect this flag either, as
+ * the work queue and irq_work logic will do the necessary
+ * synchronization for the wake ups. The only thing
+ * 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 (signal_pending(current)) {
+ ret = -EINTR;
+ break;
+ }
+
+ if (cpu == RING_BUFFER_ALL_CPUS && !ring_buffer_empty(buffer))
+ break;
+
+ if (cpu != RING_BUFFER_ALL_CPUS &&
+ !ring_buffer_empty_cpu(buffer, cpu)) {
+ unsigned long flags;
+ bool pagebusy;
+
+ if (!full)
+ break;
+
+ raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+ pagebusy = cpu_buffer->reader_page == cpu_buffer->commit_page;
+ raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+
+ if (!pagebusy)
+ break;
+ }
- if ((cpu == RING_BUFFER_ALL_CPUS && ring_buffer_empty(buffer)) ||
- (cpu != RING_BUFFER_ALL_CPUS && ring_buffer_empty_cpu(buffer, cpu)))
schedule();
+ }
finish_wait(&work->waiters, &wait);
- return 0;
+
+ return ret;
}
/**
generated by cgit v1.2.3 (git 2.0.4) at 2024-05-26 04:07:12 +0000