tracing: Add snapshot feature to instances
Add the "snapshot" file to the the multi-buffer instances.
cd /sys/kernel/debug/tracing/instances
mkdir foo
ls foo
buffer_size_kb buffer_total_size_kb events free_buffer set_event
snapshot trace trace_clock trace_marker trace_options trace_pipe
tracing_on
cat foo/snapshot
# tracer: nop
#
#
# * Snapshot is freed *
#
# Snapshot commands:
# echo 0 > snapshot : Clears and frees snapshot buffer
# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.
# Takes a snapshot of the main buffer.
# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)
# (Doesn't have to be '2' works with any number that
# is not a '0' or '1')
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 57895d4..17671bc 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4302,9 +4302,9 @@
local_irq_disable();
/* Now, we're going to swap */
if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
- update_max_tr(&global_trace, current, smp_processor_id());
+ update_max_tr(tr, current, smp_processor_id());
else
- update_max_tr_single(&global_trace, current, iter->cpu_file);
+ update_max_tr_single(tr, current, iter->cpu_file);
local_irq_enable();
break;
default:
@@ -5533,6 +5533,11 @@
trace_create_file("tracing_on", 0644, d_tracer,
tr, &rb_simple_fops);
+
+#ifdef CONFIG_TRACER_SNAPSHOT
+ trace_create_file("snapshot", 0644, d_tracer,
+ (void *)&tr->trace_cpu, &snapshot_fops);
+#endif
}
static __init int tracer_init_debugfs(void)
@@ -5574,11 +5579,6 @@
&ftrace_update_tot_cnt, &tracing_dyn_info_fops);
#endif
-#ifdef CONFIG_TRACER_SNAPSHOT
- trace_create_file("snapshot", 0644, d_tracer,
- (void *)&global_trace.trace_cpu, &snapshot_fops);
-#endif
-
create_trace_instances(d_tracer);
create_trace_options_dir(&global_trace);