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-rw-r--r--include/linux/ring_buffer.h66
1 files changed, 58 insertions, 8 deletions
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index e1b7b2173885..8670f1575fe1 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -11,7 +11,7 @@ struct ring_buffer_iter;
* Don't refer to this struct directly, use functions below.
*/
struct ring_buffer_event {
- u32 type:2, len:3, time_delta:27;
+ u32 type_len:5, time_delta:27;
u32 array[];
};
@@ -24,7 +24,8 @@ struct ring_buffer_event {
* size is variable depending on how much
* padding is needed
* If time_delta is non zero:
- * everything else same as RINGBUF_TYPE_DATA
+ * array[0] holds the actual length
+ * size = 4 + length (bytes)
*
* @RINGBUF_TYPE_TIME_EXTEND: Extend the time delta
* array[0] = time delta (28 .. 59)
@@ -35,22 +36,23 @@ struct ring_buffer_event {
* array[1..2] = tv_sec
* size = 16 bytes
*
- * @RINGBUF_TYPE_DATA: Data record
- * If len is zero:
+ * <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX:
+ * Data record
+ * If type_len is zero:
* array[0] holds the actual length
* array[1..(length+3)/4] holds data
- * size = 4 + 4 + length (bytes)
+ * size = 4 + length (bytes)
* else
- * length = len << 2
+ * length = type_len << 2
* array[0..(length+3)/4-1] holds data
* size = 4 + length (bytes)
*/
enum ring_buffer_type {
+ RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28,
RINGBUF_TYPE_PADDING,
RINGBUF_TYPE_TIME_EXTEND,
/* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */
RINGBUF_TYPE_TIME_STAMP,
- RINGBUF_TYPE_DATA,
};
unsigned ring_buffer_event_length(struct ring_buffer_event *event);
@@ -68,13 +70,54 @@ ring_buffer_event_time_delta(struct ring_buffer_event *event)
return event->time_delta;
}
+/*
+ * ring_buffer_event_discard can discard any event in the ring buffer.
+ * it is up to the caller to protect against a reader from
+ * consuming it or a writer from wrapping and replacing it.
+ *
+ * No external protection is needed if this is called before
+ * the event is commited. But in that case it would be better to
+ * use ring_buffer_discard_commit.
+ *
+ * Note, if an event that has not been committed is discarded
+ * with ring_buffer_event_discard, it must still be committed.
+ */
void ring_buffer_event_discard(struct ring_buffer_event *event);
/*
+ * ring_buffer_discard_commit will remove an event that has not
+ * ben committed yet. If this is used, then ring_buffer_unlock_commit
+ * must not be called on the discarded event. This function
+ * will try to remove the event from the ring buffer completely
+ * if another event has not been written after it.
+ *
+ * Example use:
+ *
+ * if (some_condition)
+ * ring_buffer_discard_commit(buffer, event);
+ * else
+ * ring_buffer_unlock_commit(buffer, event);
+ */
+void ring_buffer_discard_commit(struct ring_buffer *buffer,
+ struct ring_buffer_event *event);
+
+/*
* size is in bytes for each per CPU buffer.
*/
struct ring_buffer *
-ring_buffer_alloc(unsigned long size, unsigned flags);
+__ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key);
+
+/*
+ * Because the ring buffer is generic, if other users of the ring buffer get
+ * traced by ftrace, it can produce lockdep warnings. We need to keep each
+ * ring buffer's lock class separate.
+ */
+#define ring_buffer_alloc(size, flags) \
+({ \
+ static struct lock_class_key __key; \
+ __ring_buffer_alloc((size), (flags), &__key); \
+})
+
void ring_buffer_free(struct ring_buffer *buffer);
int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size);
@@ -122,6 +165,8 @@ unsigned long ring_buffer_entries(struct ring_buffer *buffer);
unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
+unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu);
+unsigned long ring_buffer_nmi_dropped_cpu(struct ring_buffer *buffer, int cpu);
u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu);
void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
@@ -137,6 +182,11 @@ void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data);
int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page,
size_t len, int cpu, int full);
+struct trace_seq;
+
+int ring_buffer_print_entry_header(struct trace_seq *s);
+int ring_buffer_print_page_header(struct trace_seq *s);
+
enum ring_buffer_flags {
RB_FL_OVERWRITE = 1 << 0,
};
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