[for-next][PATCH 14/26] tracing/boot: Add per-instance tracing_on option support

Steven Rostedt
2020-09-22T01:26:08Z

Add per-instance tracing_on option, which will be useful with
traceon/traceoff event trigger actions. For example, if we
disable tracing_on by default and set traceon and traceoff on
a pair of events, we can trace functions between the pair of
events.

Link: https://lkml.kernel.org/r/159972811538.428528.2561315102284268611.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/trace/trace_boot.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index fa0fc08c6ef8..d52d441a17e8 100644
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -40,6 +40,16 @@ trace_boot_set_instance_options(struct trace_array *tr, struct xbc_node *node)
pr_err("Failed to set option: %s\n", buf);
}

+ p = xbc_node_find_value(node, "tracing_on", NULL);
+ if (p && *p != '\0') {
+ if (kstrtoul(p, 10, &v))
+ pr_err("Failed to set tracing on: %s\n", p);
+ if (v)
+ tracer_tracing_on(tr);
+ else
+ tracer_tracing_off(tr);
+ }
+
p = xbc_node_find_value(node, "trace_clock", NULL);
if (p && *p != '\0') {
if (tracing_set_clock(tr, p) < 0)
--
2.28.0