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-rw-r--r--kernel/trace/trace_irqsoff.c152
1 files changed, 55 insertions, 97 deletions
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 73a6b0601f2e..5cf8c602b880 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -87,14 +87,22 @@ static __cacheline_aligned_in_smp unsigned long max_sequence;
#ifdef CONFIG_FUNCTION_TRACER
/*
- * irqsoff uses its own tracer function to keep the overhead down:
+ * Prologue for the preempt and irqs off function tracers.
+ *
+ * Returns 1 if it is OK to continue, and data->disabled is
+ * incremented.
+ * 0 if the trace is to be ignored, and data->disabled
+ * is kept the same.
+ *
+ * Note, this function is also used outside this ifdef but
+ * inside the #ifdef of the function graph tracer below.
+ * This is OK, since the function graph tracer is
+ * dependent on the function tracer.
*/
-static void
-irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip)
+static int func_prolog_dec(struct trace_array *tr,
+ struct trace_array_cpu **data,
+ unsigned long *flags)
{
- struct trace_array *tr = irqsoff_trace;
- struct trace_array_cpu *data;
- unsigned long flags;
long disabled;
int cpu;
@@ -106,18 +114,38 @@ irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip)
*/
cpu = raw_smp_processor_id();
if (likely(!per_cpu(tracing_cpu, cpu)))
- return;
+ return 0;
- local_save_flags(flags);
+ local_save_flags(*flags);
/* slight chance to get a false positive on tracing_cpu */
- if (!irqs_disabled_flags(flags))
- return;
+ if (!irqs_disabled_flags(*flags))
+ return 0;
- data = tr->data[cpu];
- disabled = atomic_inc_return(&data->disabled);
+ *data = tr->data[cpu];
+ disabled = atomic_inc_return(&(*data)->disabled);
if (likely(disabled == 1))
- trace_function(tr, ip, parent_ip, flags, preempt_count());
+ return 1;
+
+ atomic_dec(&(*data)->disabled);
+
+ return 0;
+}
+
+/*
+ * irqsoff uses its own tracer function to keep the overhead down:
+ */
+static void
+irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip)
+{
+ struct trace_array *tr = irqsoff_trace;
+ struct trace_array_cpu *data;
+ unsigned long flags;
+
+ if (!func_prolog_dec(tr, &data, &flags))
+ return;
+
+ trace_function(tr, ip, parent_ip, flags, preempt_count());
atomic_dec(&data->disabled);
}
@@ -155,30 +183,16 @@ static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
struct trace_array *tr = irqsoff_trace;
struct trace_array_cpu *data;
unsigned long flags;
- long disabled;
int ret;
- int cpu;
int pc;
- cpu = raw_smp_processor_id();
- if (likely(!per_cpu(tracing_cpu, cpu)))
+ if (!func_prolog_dec(tr, &data, &flags))
return 0;
- local_save_flags(flags);
- /* slight chance to get a false positive on tracing_cpu */
- if (!irqs_disabled_flags(flags))
- return 0;
-
- data = tr->data[cpu];
- disabled = atomic_inc_return(&data->disabled);
-
- if (likely(disabled == 1)) {
- pc = preempt_count();
- ret = __trace_graph_entry(tr, trace, flags, pc);
- } else
- ret = 0;
-
+ pc = preempt_count();
+ ret = __trace_graph_entry(tr, trace, flags, pc);
atomic_dec(&data->disabled);
+
return ret;
}
@@ -187,27 +201,13 @@ static void irqsoff_graph_return(struct ftrace_graph_ret *trace)
struct trace_array *tr = irqsoff_trace;
struct trace_array_cpu *data;
unsigned long flags;
- long disabled;
- int cpu;
int pc;
- cpu = raw_smp_processor_id();
- if (likely(!per_cpu(tracing_cpu, cpu)))
+ if (!func_prolog_dec(tr, &data, &flags))
return;
- local_save_flags(flags);
- /* slight chance to get a false positive on tracing_cpu */
- if (!irqs_disabled_flags(flags))
- return;
-
- data = tr->data[cpu];
- disabled = atomic_inc_return(&data->disabled);
-
- if (likely(disabled == 1)) {
- pc = preempt_count();
- __trace_graph_return(tr, trace, flags, pc);
- }
-
+ pc = preempt_count();
+ __trace_graph_return(tr, trace, flags, pc);
atomic_dec(&data->disabled);
}
@@ -229,75 +229,33 @@ static void irqsoff_trace_close(struct trace_iterator *iter)
static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
{
- u32 flags = GRAPH_TRACER_FLAGS;
-
- if (trace_flags & TRACE_ITER_LATENCY_FMT)
- flags |= TRACE_GRAPH_PRINT_DURATION;
- else
- flags |= TRACE_GRAPH_PRINT_ABS_TIME;
-
/*
* In graph mode call the graph tracer output function,
* otherwise go with the TRACE_FN event handler
*/
if (is_graph())
- return print_graph_function_flags(iter, flags);
+ return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
return TRACE_TYPE_UNHANDLED;
}
static void irqsoff_print_header(struct seq_file *s)
{
- if (is_graph()) {
- struct trace_iterator *iter = s->private;
- u32 flags = GRAPH_TRACER_FLAGS;
-
- if (trace_flags & TRACE_ITER_LATENCY_FMT) {
- /* print nothing if the buffers are empty */
- if (trace_empty(iter))
- return;
-
- print_trace_header(s, iter);
- flags |= TRACE_GRAPH_PRINT_DURATION;
- } else
- flags |= TRACE_GRAPH_PRINT_ABS_TIME;
-
- print_graph_headers_flags(s, flags);
- } else
+ if (is_graph())
+ print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
+ else
trace_default_header(s);
}
static void
-trace_graph_function(struct trace_array *tr,
- unsigned long ip, unsigned long flags, int pc)
-{
- u64 time = trace_clock_local();
- struct ftrace_graph_ent ent = {
- .func = ip,
- .depth = 0,
- };
- struct ftrace_graph_ret ret = {
- .func = ip,
- .depth = 0,
- .calltime = time,
- .rettime = time,
- };
-
- __trace_graph_entry(tr, &ent, flags, pc);
- __trace_graph_return(tr, &ret, flags, pc);
-}
-
-static void
__trace_function(struct trace_array *tr,
unsigned long ip, unsigned long parent_ip,
unsigned long flags, int pc)
{
- if (!is_graph())
+ if (is_graph())
+ trace_graph_function(tr, ip, parent_ip, flags, pc);
+ else
trace_function(tr, ip, parent_ip, flags, pc);
- else {
- trace_graph_function(tr, parent_ip, flags, pc);
- trace_graph_function(tr, ip, flags, pc);
- }
}
#else
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