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path: root/kernel/trace/trace_sched_wakeup.c
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Diffstat (limited to 'kernel/trace/trace_sched_wakeup.c')
-rw-r--r--kernel/trace/trace_sched_wakeup.c52
1 files changed, 26 insertions, 26 deletions
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index ad69f10..26185d7 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -24,6 +24,7 @@ static int __read_mostly tracer_enabled;
static struct task_struct *wakeup_task;
static int wakeup_cpu;
+static int wakeup_current_cpu;
static unsigned wakeup_prio = -1;
static int wakeup_rt;
@@ -56,33 +57,23 @@ wakeup_tracer_call(unsigned long ip, unsigned long parent_ip)
resched = ftrace_preempt_disable();
cpu = raw_smp_processor_id();
+ if (cpu != wakeup_current_cpu)
+ goto out_enable;
+
data = tr->data[cpu];
disabled = atomic_inc_return(&data->disabled);
if (unlikely(disabled != 1))
goto out;
local_irq_save(flags);
- __raw_spin_lock(&wakeup_lock);
-
- if (unlikely(!wakeup_task))
- goto unlock;
-
- /*
- * The task can't disappear because it needs to
- * wake up first, and we have the wakeup_lock.
- */
- if (task_cpu(wakeup_task) != cpu)
- goto unlock;
trace_function(tr, ip, parent_ip, flags, pc);
- unlock:
- __raw_spin_unlock(&wakeup_lock);
local_irq_restore(flags);
out:
atomic_dec(&data->disabled);
-
+ out_enable:
ftrace_preempt_enable(resched);
}
@@ -107,11 +98,18 @@ static int report_latency(cycle_t delta)
return 1;
}
+static void probe_wakeup_migrate_task(struct task_struct *task, int cpu)
+{
+ if (task != wakeup_task)
+ return;
+
+ wakeup_current_cpu = cpu;
+}
+
static void notrace
probe_wakeup_sched_switch(struct rq *rq, struct task_struct *prev,
struct task_struct *next)
{
- unsigned long latency = 0, t0 = 0, t1 = 0;
struct trace_array_cpu *data;
cycle_t T0, T1, delta;
unsigned long flags;
@@ -157,10 +155,6 @@ probe_wakeup_sched_switch(struct rq *rq, struct task_struct *prev,
trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, flags, pc);
tracing_sched_switch_trace(wakeup_trace, prev, next, flags, pc);
- /*
- * usecs conversion is slow so we try to delay the conversion
- * as long as possible:
- */
T0 = data->preempt_timestamp;
T1 = ftrace_now(cpu);
delta = T1-T0;
@@ -168,13 +162,10 @@ probe_wakeup_sched_switch(struct rq *rq, struct task_struct *prev,
if (!report_latency(delta))
goto out_unlock;
- latency = nsecs_to_usecs(delta);
-
- tracing_max_latency = delta;
- t0 = nsecs_to_usecs(T0);
- t1 = nsecs_to_usecs(T1);
-
- update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu);
+ if (likely(!is_tracing_stopped())) {
+ tracing_max_latency = delta;
+ update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu);
+ }
out_unlock:
__wakeup_reset(wakeup_trace);
@@ -244,6 +235,7 @@ probe_wakeup(struct rq *rq, struct task_struct *p, int success)
__wakeup_reset(wakeup_trace);
wakeup_cpu = task_cpu(p);
+ wakeup_current_cpu = wakeup_cpu;
wakeup_prio = p->prio;
wakeup_task = p;
@@ -293,6 +285,13 @@ static void start_wakeup_tracer(struct trace_array *tr)
goto fail_deprobe_wake_new;
}
+ ret = register_trace_sched_migrate_task(probe_wakeup_migrate_task);
+ if (ret) {
+ pr_info("wakeup trace: Couldn't activate tracepoint"
+ " probe to kernel_sched_migrate_task\n");
+ return;
+ }
+
wakeup_reset(tr);
/*
@@ -325,6 +324,7 @@ static void stop_wakeup_tracer(struct trace_array *tr)
unregister_trace_sched_switch(probe_wakeup_sched_switch);
unregister_trace_sched_wakeup_new(probe_wakeup);
unregister_trace_sched_wakeup(probe_wakeup);
+ unregister_trace_sched_migrate_task(probe_wakeup_migrate_task);
}
static int __wakeup_tracer_init(struct trace_array *tr)
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