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Subject[for-next][PATCH 2/8] tracing: Move tracing_max_latency into trace_array
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

In preparation for letting the latency tracers be used by instances,
remove the global tracing_max_latency variable and add a max_latency
field to the trace_array that the latency tracers will now use.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace.c | 14 ++++++--------
kernel/trace/trace.h | 3 +--
kernel/trace/trace_irqsoff.c | 14 +++++++-------
kernel/trace/trace_sched_wakeup.c | 12 ++++++------
kernel/trace/trace_selftest.c | 26 +++++++++++++-------------
5 files changed, 33 insertions(+), 36 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index fdd33aa..f5fc56b 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -982,8 +982,6 @@ static arch_spinlock_t ftrace_max_lock =
unsigned long __read_mostly tracing_thresh;

#ifdef CONFIG_TRACER_MAX_TRACE
-unsigned long __read_mostly tracing_max_latency;
-
/*
* Copy the new maximum trace into the separate maximum-trace
* structure. (this way the maximum trace is permanently saved,
@@ -1000,7 +998,7 @@ __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
max_buf->cpu = cpu;
max_buf->time_start = data->preempt_timestamp;

- max_data->saved_latency = tracing_max_latency;
+ max_data->saved_latency = tr->max_latency;
max_data->critical_start = data->critical_start;
max_data->critical_end = data->critical_end;

@@ -6328,6 +6326,11 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
trace_create_file("tracing_on", 0644, d_tracer,
tr, &rb_simple_fops);

+#ifdef CONFIG_TRACER_MAX_TRACE
+ trace_create_file("tracing_max_latency", 0644, d_tracer,
+ &tr->max_latency, &tracing_max_lat_fops);
+#endif
+
if (ftrace_create_function_files(tr, d_tracer))
WARN(1, "Could not allocate function filter files");

@@ -6353,11 +6356,6 @@ static __init int tracer_init_debugfs(void)

init_tracer_debugfs(&global_trace, d_tracer);

-#ifdef CONFIG_TRACER_MAX_TRACE
- trace_create_file("tracing_max_latency", 0644, d_tracer,
- &tracing_max_latency, &tracing_max_lat_fops);
-#endif
-
trace_create_file("tracing_thresh", 0644, d_tracer,
&tracing_thresh, &tracing_max_lat_fops);

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index df5256b..644a8b5 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -190,6 +190,7 @@ struct trace_array {
*/
struct trace_buffer max_buffer;
bool allocated_snapshot;
+ unsigned long max_latency;
#endif
int buffer_disabled;
#ifdef CONFIG_FTRACE_SYSCALLS
@@ -599,8 +600,6 @@ extern unsigned long nsecs_to_usecs(unsigned long nsecs);
extern unsigned long tracing_thresh;

#ifdef CONFIG_TRACER_MAX_TRACE
-extern unsigned long tracing_max_latency;
-
void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
void update_max_tr_single(struct trace_array *tr,
struct task_struct *tsk, int cpu);
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index b5cb047..40aa300 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -170,7 +170,7 @@ irqsoff_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
for_each_possible_cpu(cpu)
per_cpu(tracing_cpu, cpu) = 0;

- tracing_max_latency = 0;
+ tr->max_latency = 0;
tracing_reset_online_cpus(&irqsoff_trace->trace_buffer);

return start_irqsoff_tracer(irqsoff_trace, set);
@@ -297,13 +297,13 @@ static void irqsoff_print_header(struct seq_file *s)
/*
* Should this new latency be reported/recorded?
*/
-static int report_latency(cycle_t delta)
+static int report_latency(struct trace_array *tr, cycle_t delta)
{
if (tracing_thresh) {
if (delta < tracing_thresh)
return 0;
} else {
- if (delta <= tracing_max_latency)
+ if (delta <= tr->max_latency)
return 0;
}
return 1;
@@ -327,13 +327,13 @@ check_critical_timing(struct trace_array *tr,

pc = preempt_count();

- if (!report_latency(delta))
+ if (!report_latency(tr, delta))
goto out;

raw_spin_lock_irqsave(&max_trace_lock, flags);

/* check if we are still the max latency */
- if (!report_latency(delta))
+ if (!report_latency(tr, delta))
goto out_unlock;

__trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
@@ -346,7 +346,7 @@ check_critical_timing(struct trace_array *tr,
data->critical_end = parent_ip;

if (likely(!is_tracing_stopped())) {
- tracing_max_latency = delta;
+ tr->max_latency = delta;
update_max_tr_single(tr, current, cpu);
}

@@ -605,7 +605,7 @@ static void __irqsoff_tracer_init(struct trace_array *tr)
set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);

- tracing_max_latency = 0;
+ tr->max_latency = 0;
irqsoff_trace = tr;
/* make sure that the tracer is visible */
smp_wmb();
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 4dd986d..41e0b8a 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -218,7 +218,7 @@ wakeup_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
stop_func_tracer(tr, !set);

wakeup_reset(wakeup_trace);
- tracing_max_latency = 0;
+ tr->max_latency = 0;

return start_func_tracer(tr, set);
}
@@ -344,13 +344,13 @@ static void wakeup_print_header(struct seq_file *s)
/*
* Should this new latency be reported/recorded?
*/
-static int report_latency(cycle_t delta)
+static int report_latency(struct trace_array *tr, cycle_t delta)
{
if (tracing_thresh) {
if (delta < tracing_thresh)
return 0;
} else {
- if (delta <= tracing_max_latency)
+ if (delta <= tr->max_latency)
return 0;
}
return 1;
@@ -418,11 +418,11 @@ probe_wakeup_sched_switch(void *ignore,
T1 = ftrace_now(cpu);
delta = T1-T0;

- if (!report_latency(delta))
+ if (!report_latency(wakeup_trace, delta))
goto out_unlock;

if (likely(!is_tracing_stopped())) {
- tracing_max_latency = delta;
+ wakeup_trace->max_latency = delta;
update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu);
}

@@ -609,7 +609,7 @@ static int __wakeup_tracer_init(struct trace_array *tr)
set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1);
set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1);

- tracing_max_latency = 0;
+ tr->max_latency = 0;
wakeup_trace = tr;
ftrace_init_array_ops(tr, wakeup_tracer_call);
start_wakeup_tracer(tr);
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 519d04a..ac31858 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -807,7 +807,7 @@ out:
int
trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
{
- unsigned long save_max = tracing_max_latency;
+ unsigned long save_max = tr->max_latency;
unsigned long count;
int ret;

@@ -819,7 +819,7 @@ trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
}

/* reset the max latency */
- tracing_max_latency = 0;
+ tr->max_latency = 0;
/* disable interrupts for a bit */
local_irq_disable();
udelay(100);
@@ -846,7 +846,7 @@ trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
ret = -1;
}

- tracing_max_latency = save_max;
+ tr->max_latency = save_max;

return ret;
}
@@ -856,7 +856,7 @@ trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
int
trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
{
- unsigned long save_max = tracing_max_latency;
+ unsigned long save_max = tr->max_latency;
unsigned long count;
int ret;

@@ -881,7 +881,7 @@ trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
}

/* reset the max latency */
- tracing_max_latency = 0;
+ tr->max_latency = 0;
/* disable preemption for a bit */
preempt_disable();
udelay(100);
@@ -908,7 +908,7 @@ trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
ret = -1;
}

- tracing_max_latency = save_max;
+ tr->max_latency = save_max;

return ret;
}
@@ -918,7 +918,7 @@ trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
int
trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *tr)
{
- unsigned long save_max = tracing_max_latency;
+ unsigned long save_max = tr->max_latency;
unsigned long count;
int ret;

@@ -943,7 +943,7 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *
}

/* reset the max latency */
- tracing_max_latency = 0;
+ tr->max_latency = 0;

/* disable preemption and interrupts for a bit */
preempt_disable();
@@ -978,7 +978,7 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *
}

/* do the test by disabling interrupts first this time */
- tracing_max_latency = 0;
+ tr->max_latency = 0;
tracing_start();
trace->start(tr);

@@ -1009,7 +1009,7 @@ out:
tracing_start();
out_no_start:
trace->reset(tr);
- tracing_max_latency = save_max;
+ tr->max_latency = save_max;

return ret;
}
@@ -1062,7 +1062,7 @@ static int trace_wakeup_test_thread(void *data)
int
trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
{
- unsigned long save_max = tracing_max_latency;
+ unsigned long save_max = tr->max_latency;
struct task_struct *p;
struct completion is_ready;
unsigned long count;
@@ -1088,7 +1088,7 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
}

/* reset the max latency */
- tracing_max_latency = 0;
+ tr->max_latency = 0;

while (p->on_rq) {
/*
@@ -1118,7 +1118,7 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
trace->reset(tr);
tracing_start();

- tracing_max_latency = save_max;
+ tr->max_latency = save_max;

/* kill the thread */
kthread_stop(p);
--
1.8.5.3



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