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tracing: Add trace_total_entries() / trace_total_entries_cpu() 

These two new exported functions will be used in a future patch by
kdb_ftdump() to quickly skip all but the last few trace entries.

Link: http://lkml.kernel.org/r/20190319171206.97107-2-dianders@chromium.org

Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Douglas Anderson 2019-03-19 10:12:05 -07:00 committed by Steven Rostedt (VMware)
parent dbfe67334a
commit ecffc8a8c7
2 changed files with 53 additions and 15 deletions
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65
kernel/trace/trace.c
View File

@ -3492,34 +3492,69 @@ static void s_stop(struct seq_file *m, void *p)
trace_event_read_unlock();
}
static void
get_total_entries_cpu(struct trace_buffer *buf, unsigned long *total,
unsigned long *entries, int cpu)
{
unsigned long count;
count = ring_buffer_entries_cpu(buf->buffer, cpu);
/*
* If this buffer has skipped entries, then we hold all
* entries for the trace and we need to ignore the
* ones before the time stamp.
*/
if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
/* total is the same as the entries */
*total = count;
} else
*total = count +
ring_buffer_overrun_cpu(buf->buffer, cpu);
*entries = count;
}
static void
get_total_entries(struct trace_buffer *buf,
unsigned long *total, unsigned long *entries)
{
unsigned long count;
unsigned long t, e;
int cpu;
*total = 0;
*entries = 0;
for_each_tracing_cpu(cpu) {
count = ring_buffer_entries_cpu(buf->buffer, cpu);
/*
* If this buffer has skipped entries, then we hold all
* entries for the trace and we need to ignore the
* ones before the time stamp.
*/
if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
/* total is the same as the entries */
*total += count;
} else
*total += count +
ring_buffer_overrun_cpu(buf->buffer, cpu);
*entries += count;
get_total_entries_cpu(buf, &t, &e, cpu);
*total += t;
*entries += e;
}
}
unsigned long trace_total_entries_cpu(struct trace_array *tr, int cpu)
{
unsigned long total, entries;
if (!tr)
tr = &global_trace;
get_total_entries_cpu(&tr->trace_buffer, &total, &entries, cpu);
return entries;
}
unsigned long trace_total_entries(struct trace_array *tr)
{
unsigned long total, entries;
if (!tr)
tr = &global_trace;
get_total_entries(&tr->trace_buffer, &total, &entries);
return entries;
}
static void print_lat_help_header(struct seq_file *m)
{
seq_puts(m, "# _------=> CPU# \n"

3
kernel/trace/trace.h
View File

@ -721,6 +721,9 @@ void trace_init_global_iter(struct trace_iterator *iter);
void tracing_iter_reset(struct trace_iterator *iter, int cpu);
unsigned long trace_total_entries_cpu(struct trace_array *tr, int cpu);
unsigned long trace_total_entries(struct trace_array *tr);
void trace_function(struct trace_array *tr,
unsigned long ip,
unsigned long parent_ip,