ftrace: Have funcgraph-args take affect during tracing

Currently, when function_graph is started, it looks at the option
funcgraph-args, and if it is set, it will enable tracing of the arguments.

But if tracing is already running, and the user enables funcgraph-args, it
will have no effect. Instead, it should enable argument tracing when it is
enabled, even if it means disabling the function graph tracing for a short
time in order to do the transition.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Guo Ren <guoren@kernel.org>
Cc: Donglin Peng <dolinux.peng@gmail.com>
Cc: Zheng Yejian <zhengyejian@huaweicloud.com>
Link: https://lore.kernel.org/20250227185822.978998710@goodmis.org
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt 2025-02-27 13:58:07 -05:00 committed by Steven Rostedt (Google)
parent ff5c9c576e
commit c7a60a733c

View File

@ -464,7 +464,7 @@ static int graph_trace_init(struct trace_array *tr)
else
tr->gops->retfunc = trace_graph_return;
/* Make gops functions are visible before we start tracing */
/* Make gops functions visible before we start tracing */
smp_mb();
ret = register_ftrace_graph(tr->gops);
@ -475,6 +475,28 @@ static int graph_trace_init(struct trace_array *tr)
return 0;
}
static int ftrace_graph_trace_args(struct trace_array *tr, int set)
{
trace_func_graph_ent_t entry;
if (set)
entry = trace_graph_entry_args;
else
entry = trace_graph_entry;
/* See if there's any changes */
if (tr->gops->entryfunc == entry)
return 0;
unregister_ftrace_graph(tr->gops);
tr->gops->entryfunc = entry;
/* Make gops functions visible before we start tracing */
smp_mb();
return register_ftrace_graph(tr->gops);
}
static void graph_trace_reset(struct trace_array *tr)
{
tracing_stop_cmdline_record();
@ -1607,6 +1629,9 @@ func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
if (bit == TRACE_GRAPH_GRAPH_TIME)
ftrace_graph_graph_time_control(set);
if (bit == TRACE_GRAPH_ARGS)
return ftrace_graph_trace_args(tr, set);
return 0;
}