Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[~andy/linux] / kernel / trace / ring_buffer.c

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 4cb5e51471656a50aa2897f42ae6c4aee5333c00..ce8514feedcdf29c181dda4972eb7a53cd0df04e 100644 (file)
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -460,9 +460,10 @@ struct ring_buffer_per_cpu {
        unsigned long                   lost_events;
        unsigned long                   last_overrun;
        local_t                         entries_bytes;
-       local_t                         commit_overrun;
-       local_t                         overrun;
        local_t                         entries;
+       local_t                         overrun;
+       local_t                         commit_overrun;
+       local_t                         dropped_events;
        local_t                         committing;
        local_t                         commits;
        unsigned long                   read;
@@ -1822,7 +1823,7 @@ rb_add_time_stamp(struct ring_buffer_event *event, u64 delta)
 }
 
 /**
- * ring_buffer_update_event - update event type and data
+ * rb_update_event - update event type and data
  * @event: the even to update
  * @type: the type of event
  * @length: the size of the event field in the ring buffer
@@ -2157,8 +2158,10 @@ rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer,
                         * If we are not in overwrite mode,
                         * this is easy, just stop here.
                         */
-                       if (!(buffer->flags & RB_FL_OVERWRITE))
+                       if (!(buffer->flags & RB_FL_OVERWRITE)) {
+                               local_inc(&cpu_buffer->dropped_events);
                                goto out_reset;
+                       }
 
                        ret = rb_handle_head_page(cpu_buffer,
                                                  tail_page,
@@ -2722,8 +2725,8 @@ EXPORT_SYMBOL_GPL(ring_buffer_discard_commit);
  * and not the length of the event which would hold the header.
  */
 int ring_buffer_write(struct ring_buffer *buffer,
-                       unsigned long length,
-                       void *data)
+                     unsigned long length,
+                     void *data)
 {
        struct ring_buffer_per_cpu *cpu_buffer;
        struct ring_buffer_event *event;
@@ -2931,12 +2934,12 @@ rb_num_of_entries(struct ring_buffer_per_cpu *cpu_buffer)
  * @buffer: The ring buffer
  * @cpu: The per CPU buffer to read from.
  */
-unsigned long ring_buffer_oldest_event_ts(struct ring_buffer *buffer, int cpu)
+u64 ring_buffer_oldest_event_ts(struct ring_buffer *buffer, int cpu)
 {
        unsigned long flags;
        struct ring_buffer_per_cpu *cpu_buffer;
        struct buffer_page *bpage;
-       unsigned long ret = 0;
+       u64 ret = 0;
 
        if (!cpumask_test_cpu(cpu, buffer->cpumask))
                return 0;
@@ -2998,7 +3001,8 @@ unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu)
 EXPORT_SYMBOL_GPL(ring_buffer_entries_cpu);
 
 /**
- * ring_buffer_overrun_cpu - get the number of overruns in a cpu_buffer
+ * ring_buffer_overrun_cpu - get the number of overruns caused by the ring
+ * buffer wrapping around (only if RB_FL_OVERWRITE is on).
  * @buffer: The ring buffer
  * @cpu: The per CPU buffer to get the number of overruns from
  */
@@ -3018,7 +3022,9 @@ unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu)
 EXPORT_SYMBOL_GPL(ring_buffer_overrun_cpu);
 
 /**
- * ring_buffer_commit_overrun_cpu - get the number of overruns caused by commits
+ * ring_buffer_commit_overrun_cpu - get the number of overruns caused by
+ * commits failing due to the buffer wrapping around while there are uncommitted
+ * events, such as during an interrupt storm.
  * @buffer: The ring buffer
  * @cpu: The per CPU buffer to get the number of overruns from
  */
@@ -3038,6 +3044,28 @@ ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu)
 }
 EXPORT_SYMBOL_GPL(ring_buffer_commit_overrun_cpu);
 
+/**
+ * ring_buffer_dropped_events_cpu - get the number of dropped events caused by
+ * the ring buffer filling up (only if RB_FL_OVERWRITE is off).
+ * @buffer: The ring buffer
+ * @cpu: The per CPU buffer to get the number of overruns from
+ */
+unsigned long
+ring_buffer_dropped_events_cpu(struct ring_buffer *buffer, int cpu)
+{
+       struct ring_buffer_per_cpu *cpu_buffer;
+       unsigned long ret;
+
+       if (!cpumask_test_cpu(cpu, buffer->cpumask))
+               return 0;
+
+       cpu_buffer = buffer->buffers[cpu];
+       ret = local_read(&cpu_buffer->dropped_events);
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_dropped_events_cpu);
+
 /**
  * ring_buffer_entries - get the number of entries in a buffer
  * @buffer: The ring buffer
@@ -3874,9 +3902,10 @@ rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer)
        local_set(&cpu_buffer->reader_page->page->commit, 0);
        cpu_buffer->reader_page->read = 0;
 
-       local_set(&cpu_buffer->commit_overrun, 0);
        local_set(&cpu_buffer->entries_bytes, 0);
        local_set(&cpu_buffer->overrun, 0);
+       local_set(&cpu_buffer->commit_overrun, 0);
+       local_set(&cpu_buffer->dropped_events, 0);
        local_set(&cpu_buffer->entries, 0);
        local_set(&cpu_buffer->committing, 0);
        local_set(&cpu_buffer->commits, 0);