[for-next][PATCH 2/4] tracing: Kill the dead code in probe_sched_switch() and probe_sched_wakeup()

From: Steven Rostedt
Date: Tue Nov 04 2014 - 08:50:05 EST


From: Oleg Nesterov <oleg@xxxxxxxxxx>

After the previous patch it is clear that "tracer_enabled" can never be
true, we can remove the "if (tracer_enabled)" code in probe_sched_switch()
and probe_sched_wakeup(). Plus we can obviously remove tracer_enabled,
ctx_trace, and sched_stopped as well.

Link: http://lkml.kernel.org/p/20140723193503.GA30217@xxxxxxxxxx

Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/trace/trace_sched_switch.c | 40 ---------------------------------------
1 file changed, 40 deletions(-)

diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index 3b60301c59d2..f7c7f4f1544c 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -14,12 +14,8 @@

#include "trace.h"

-static struct trace_array *ctx_trace;
-static int __read_mostly tracer_enabled;
static int sched_ref;
static DEFINE_MUTEX(sched_register_mutex);
-static int sched_stopped;
-

void
tracing_sched_switch_trace(struct trace_array *tr,
@@ -52,29 +48,11 @@ tracing_sched_switch_trace(struct trace_array *tr,
static void
probe_sched_switch(void *ignore, struct task_struct *prev, struct task_struct *next)
{
- struct trace_array_cpu *data;
- unsigned long flags;
- int cpu;
- int pc;
-
if (unlikely(!sched_ref))
return;

tracing_record_cmdline(prev);
tracing_record_cmdline(next);
-
- if (!tracer_enabled || sched_stopped)
- return;
-
- pc = preempt_count();
- local_irq_save(flags);
- cpu = raw_smp_processor_id();
- data = per_cpu_ptr(ctx_trace->trace_buffer.data, cpu);
-
- if (likely(!atomic_read(&data->disabled)))
- tracing_sched_switch_trace(ctx_trace, prev, next, flags, pc);
-
- local_irq_restore(flags);
}

void
@@ -108,28 +86,10 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
static void
probe_sched_wakeup(void *ignore, struct task_struct *wakee, int success)
{
- struct trace_array_cpu *data;
- unsigned long flags;
- int cpu, pc;
-
if (unlikely(!sched_ref))
return;

tracing_record_cmdline(current);
-
- if (!tracer_enabled || sched_stopped)
- return;
-
- pc = preempt_count();
- local_irq_save(flags);
- cpu = raw_smp_processor_id();
- data = per_cpu_ptr(ctx_trace->trace_buffer.data, cpu);
-
- if (likely(!atomic_read(&data->disabled)))
- tracing_sched_wakeup_trace(ctx_trace, wakee, current,
- flags, pc);
-
- local_irq_restore(flags);
}

static int tracing_sched_register(void)
--
2.1.1


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