diff options
| -rw-r--r-- | kernel/trace/trace_mmiotrace.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c index 6d2edbdde93..d0f649a2203 100644 --- a/kernel/trace/trace_mmiotrace.c +++ b/kernel/trace/trace_mmiotrace.c @@ -17,11 +17,13 @@ struct header_iter { }; static struct trace_array *mmio_trace_array; +static bool overrun_detected; static void mmio_reset_data(struct trace_array *tr) { int cpu; + overrun_detected = false; tr->time_start = ftrace_now(tr->cpu); for_each_online_cpu(cpu) @@ -124,12 +126,34 @@ static void mmio_close(struct trace_iterator *iter) iter->private = NULL; } +static unsigned long count_overruns(struct trace_iterator *iter) +{ + int cpu; + unsigned long cnt = 0; + for_each_online_cpu(cpu) { + cnt += iter->overrun[cpu]; + iter->overrun[cpu] = 0; + } + return cnt; +} + static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { ssize_t ret; struct header_iter *hiter = iter->private; struct trace_seq *s = &iter->seq; + unsigned long n; + + n = count_overruns(iter); + if (n) { + /* XXX: This is later than where events were lost. */ + trace_seq_printf(s, "MARK 0.000000 Lost %lu events.\n", n); + if (!overrun_detected) + pr_warning("mmiotrace has lost events.\n"); + overrun_detected = true; + goto print_out; + } if (!hiter) return 0; @@ -142,6 +166,7 @@ static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp, iter->private = NULL; } +print_out: ret = trace_seq_to_user(s, ubuf, cnt); return (ret == -EBUSY) ? 0 : ret; } |