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tracing: Graph support for wakeup tracer
Add function graph support for wakeup latency tracer. The graph output is enabled by setting the 'display-graph' trace option. Signed-off-by: Jiri Olsa <jolsa@redhat.com> LKML-Reference: <1285243253-7372-4-git-send-email-jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Jiri Olsa
Steven Rostedt
parent
0a772620a2
commit
7495a5beaa
@ -31,13 +31,33 @@ static int wakeup_rt;
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static arch_spinlock_t wakeup_lock =
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(arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
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static void wakeup_reset(struct trace_array *tr);
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static void __wakeup_reset(struct trace_array *tr);
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static int wakeup_graph_entry(struct ftrace_graph_ent *trace);
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static void wakeup_graph_return(struct ftrace_graph_ret *trace);
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static int save_lat_flag;
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#define TRACE_DISPLAY_GRAPH 1
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static struct tracer_opt trace_opts[] = {
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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/* display latency trace as call graph */
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{ TRACER_OPT(display-graph, TRACE_DISPLAY_GRAPH) },
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#endif
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{ } /* Empty entry */
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};
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static struct tracer_flags tracer_flags = {
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.val = 0,
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.opts = trace_opts,
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};
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#define is_graph() (tracer_flags.val & TRACE_DISPLAY_GRAPH)
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#ifdef CONFIG_FUNCTION_TRACER
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/*
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* irqsoff uses its own tracer function to keep the overhead down:
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* wakeup uses its own tracer function to keep the overhead down:
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*/
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static void
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wakeup_tracer_call(unsigned long ip, unsigned long parent_ip)
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@ -80,8 +100,191 @@ static struct ftrace_ops trace_ops __read_mostly =
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{
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.func = wakeup_tracer_call,
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};
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static int start_func_tracer(int graph)
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{
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int ret;
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if (!graph)
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ret = register_ftrace_function(&trace_ops);
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else
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ret = register_ftrace_graph(&wakeup_graph_return,
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&wakeup_graph_entry);
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if (!ret && tracing_is_enabled())
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tracer_enabled = 1;
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else
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tracer_enabled = 0;
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return ret;
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}
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static void stop_func_tracer(int graph)
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{
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tracer_enabled = 0;
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if (!graph)
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unregister_ftrace_function(&trace_ops);
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else
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unregister_ftrace_graph();
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}
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#endif /* CONFIG_FUNCTION_TRACER */
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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static int wakeup_set_flag(u32 old_flags, u32 bit, int set)
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{
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if (!(bit & TRACE_DISPLAY_GRAPH))
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return -EINVAL;
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if (!(is_graph() ^ set))
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return 0;
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stop_func_tracer(!set);
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wakeup_reset(wakeup_trace);
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tracing_max_latency = 0;
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return start_func_tracer(set);
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}
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static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
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{
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struct trace_array *tr = wakeup_trace;
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struct trace_array_cpu *data;
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unsigned long flags;
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long disabled;
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int cpu, pc, ret = 0;
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if (likely(!wakeup_task))
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return 0;
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pc = preempt_count();
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preempt_disable_notrace();
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cpu = raw_smp_processor_id();
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if (cpu != wakeup_current_cpu)
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goto out_enable;
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data = tr->data[cpu];
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disabled = atomic_inc_return(&data->disabled);
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if (unlikely(disabled != 1))
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goto out;
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local_save_flags(flags);
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ret = __trace_graph_entry(tr, trace, flags, pc);
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out:
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atomic_dec(&data->disabled);
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out_enable:
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preempt_enable_notrace();
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return ret;
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}
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static void wakeup_graph_return(struct ftrace_graph_ret *trace)
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{
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struct trace_array *tr = wakeup_trace;
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struct trace_array_cpu *data;
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unsigned long flags;
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long disabled;
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int cpu, pc;
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if (likely(!wakeup_task))
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return;
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pc = preempt_count();
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preempt_disable_notrace();
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cpu = raw_smp_processor_id();
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if (cpu != wakeup_current_cpu)
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goto out_enable;
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data = tr->data[cpu];
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disabled = atomic_inc_return(&data->disabled);
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if (unlikely(disabled != 1))
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goto out;
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local_save_flags(flags);
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__trace_graph_return(tr, trace, flags, pc);
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out:
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atomic_dec(&data->disabled);
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out_enable:
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preempt_enable_notrace();
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return;
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}
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static void wakeup_trace_open(struct trace_iterator *iter)
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{
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if (is_graph())
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graph_trace_open(iter);
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}
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static void wakeup_trace_close(struct trace_iterator *iter)
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{
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if (iter->private)
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graph_trace_close(iter);
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}
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#define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_PROC)
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static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
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{
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/*
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* In graph mode call the graph tracer output function,
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* otherwise go with the TRACE_FN event handler
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*/
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if (is_graph())
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return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS);
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return TRACE_TYPE_UNHANDLED;
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}
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static void wakeup_print_header(struct seq_file *s)
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{
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if (is_graph())
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print_graph_headers_flags(s, GRAPH_TRACER_FLAGS);
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else
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trace_default_header(s);
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}
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static void
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__trace_function(struct trace_array *tr,
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unsigned long ip, unsigned long parent_ip,
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unsigned long flags, int pc)
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{
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if (is_graph())
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trace_graph_function(tr, ip, parent_ip, flags, pc);
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else
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trace_function(tr, ip, parent_ip, flags, pc);
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}
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#else
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#define __trace_function trace_function
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static int wakeup_set_flag(u32 old_flags, u32 bit, int set)
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{
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return -EINVAL;
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}
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static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
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{
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return -1;
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}
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static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
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{
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return TRACE_TYPE_UNHANDLED;
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}
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static void wakeup_graph_return(struct ftrace_graph_ret *trace) { }
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static void wakeup_print_header(struct seq_file *s) { }
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static void wakeup_trace_open(struct trace_iterator *iter) { }
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static void wakeup_trace_close(struct trace_iterator *iter) { }
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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/*
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* Should this new latency be reported/recorded?
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*/
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@ -152,7 +355,7 @@ probe_wakeup_sched_switch(void *ignore,
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/* The task we are waiting for is waking up */
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data = wakeup_trace->data[wakeup_cpu];
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trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, flags, pc);
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__trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, flags, pc);
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tracing_sched_switch_trace(wakeup_trace, prev, next, flags, pc);
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T0 = data->preempt_timestamp;
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@ -252,7 +455,7 @@ probe_wakeup(void *ignore, struct task_struct *p, int success)
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* is not called by an assembly function (where as schedule is)
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* it should be safe to use it here.
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*/
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trace_function(wakeup_trace, CALLER_ADDR1, CALLER_ADDR2, flags, pc);
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__trace_function(wakeup_trace, CALLER_ADDR1, CALLER_ADDR2, flags, pc);
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out_locked:
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arch_spin_unlock(&wakeup_lock);
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@ -303,12 +506,8 @@ static void start_wakeup_tracer(struct trace_array *tr)
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*/
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smp_wmb();
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register_ftrace_function(&trace_ops);
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if (tracing_is_enabled())
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tracer_enabled = 1;
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else
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tracer_enabled = 0;
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if (start_func_tracer(is_graph()))
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printk(KERN_ERR "failed to start wakeup tracer\n");
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return;
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fail_deprobe_wake_new:
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@ -320,7 +519,7 @@ fail_deprobe:
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static void stop_wakeup_tracer(struct trace_array *tr)
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{
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tracer_enabled = 0;
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unregister_ftrace_function(&trace_ops);
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stop_func_tracer(is_graph());
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unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL);
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unregister_trace_sched_wakeup_new(probe_wakeup, NULL);
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unregister_trace_sched_wakeup(probe_wakeup, NULL);
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@ -379,9 +578,15 @@ static struct tracer wakeup_tracer __read_mostly =
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.start = wakeup_tracer_start,
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.stop = wakeup_tracer_stop,
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.print_max = 1,
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.print_header = wakeup_print_header,
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.print_line = wakeup_print_line,
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.flags = &tracer_flags,
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.set_flag = wakeup_set_flag,
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#ifdef CONFIG_FTRACE_SELFTEST
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.selftest = trace_selftest_startup_wakeup,
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#endif
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.open = wakeup_trace_open,
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.close = wakeup_trace_close,
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.use_max_tr = 1,
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};
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@ -394,9 +599,15 @@ static struct tracer wakeup_rt_tracer __read_mostly =
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.stop = wakeup_tracer_stop,
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.wait_pipe = poll_wait_pipe,
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.print_max = 1,
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.print_header = wakeup_print_header,
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.print_line = wakeup_print_line,
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.flags = &tracer_flags,
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.set_flag = wakeup_set_flag,
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#ifdef CONFIG_FTRACE_SELFTEST
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.selftest = trace_selftest_startup_wakeup,
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#endif
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.open = wakeup_trace_open,
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.close = wakeup_trace_close,
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.use_max_tr = 1,
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};
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