tracing: Allow irq/preempt tracers to be used by instances
The irqsoff, preemptoff and preemptirqsoff tracers can now be used by
instances. But they may only be used by one instance at a time (including
the top level directory). This allows multiple tracers to run while the
irqsoff (and friends) tracer is running simultaneously.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 40aa300..9bb104f7 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -597,8 +597,13 @@
unregister_irqsoff_function(tr, graph);
}
-static void __irqsoff_tracer_init(struct trace_array *tr)
+static bool irqsoff_busy;
+
+static int __irqsoff_tracer_init(struct trace_array *tr)
{
+ if (irqsoff_busy)
+ return -EBUSY;
+
save_flags = trace_flags;
/* non overwrite screws up the latency tracers */
@@ -617,6 +622,9 @@
if (start_irqsoff_tracer(tr, (tr->flags & TRACE_ARRAY_FL_GLOBAL &&
is_graph())))
printk(KERN_ERR "failed to start irqsoff tracer\n");
+
+ irqsoff_busy = true;
+ return 0;
}
static void irqsoff_tracer_reset(struct trace_array *tr)
@@ -629,6 +637,8 @@
set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag);
set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag);
ftrace_reset_array_ops(tr);
+
+ irqsoff_busy = false;
}
static void irqsoff_tracer_start(struct trace_array *tr)
@@ -646,8 +656,7 @@
{
trace_type = TRACER_IRQS_OFF;
- __irqsoff_tracer_init(tr);
- return 0;
+ return __irqsoff_tracer_init(tr);
}
static struct tracer irqsoff_tracer __read_mostly =
{
@@ -667,6 +676,7 @@
#endif
.open = irqsoff_trace_open,
.close = irqsoff_trace_close,
+ .allow_instances = true,
.use_max_tr = true,
};
# define register_irqsoff(trace) register_tracer(&trace)
@@ -679,8 +689,7 @@
{
trace_type = TRACER_PREEMPT_OFF;
- __irqsoff_tracer_init(tr);
- return 0;
+ return __irqsoff_tracer_init(tr);
}
static struct tracer preemptoff_tracer __read_mostly =
@@ -701,6 +710,7 @@
#endif
.open = irqsoff_trace_open,
.close = irqsoff_trace_close,
+ .allow_instances = true,
.use_max_tr = true,
};
# define register_preemptoff(trace) register_tracer(&trace)
@@ -715,8 +725,7 @@
{
trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;
- __irqsoff_tracer_init(tr);
- return 0;
+ return __irqsoff_tracer_init(tr);
}
static struct tracer preemptirqsoff_tracer __read_mostly =
@@ -737,6 +746,7 @@
#endif
.open = irqsoff_trace_open,
.close = irqsoff_trace_close,
+ .allow_instances = true,
.use_max_tr = true,
};
