tracing: only show tracing_max_latency when latency tracer configured
The tracing_max_latency file should only be present when one of the
latency tracers ({preempt|irqs}off, wakeup*) are enabled.
This patch also removes tracing_thresh when latency tracers are not
enabled, as well as compiles out code that is only used for latency
tracers.
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt
Steven Rostedt
Родитель
c0729be99c
Коммит
5d4a9dba2d
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@ -43,9 +43,6 @@
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#define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE)
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unsigned long __read_mostly tracing_max_latency;
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unsigned long __read_mostly tracing_thresh;
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/*
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* On boot up, the ring buffer is set to the minimum size, so that
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* we do not waste memory on systems that are not using tracing.
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@ -338,45 +335,6 @@ static struct {
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int trace_clock_id;
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/*
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* ftrace_max_lock is used to protect the swapping of buffers
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* when taking a max snapshot. The buffers themselves are
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* protected by per_cpu spinlocks. But the action of the swap
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* needs its own lock.
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*
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* This is defined as a raw_spinlock_t in order to help
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* with performance when lockdep debugging is enabled.
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*/
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static raw_spinlock_t ftrace_max_lock =
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(raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
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/*
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* Copy the new maximum trace into the separate maximum-trace
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* structure. (this way the maximum trace is permanently saved,
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* for later retrieval via /sys/kernel/debug/tracing/latency_trace)
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*/
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static void
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__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
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{
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struct trace_array_cpu *data = tr->data[cpu];
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max_tr.cpu = cpu;
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max_tr.time_start = data->preempt_timestamp;
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data = max_tr.data[cpu];
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data->saved_latency = tracing_max_latency;
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memcpy(data->comm, tsk->comm, TASK_COMM_LEN);
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data->pid = tsk->pid;
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data->uid = task_uid(tsk);
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data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
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data->policy = tsk->policy;
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data->rt_priority = tsk->rt_priority;
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/* record this tasks comm */
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tracing_record_cmdline(tsk);
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}
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ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
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{
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int len;
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@ -420,6 +378,53 @@ static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
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return cnt;
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}
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/*
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* ftrace_max_lock is used to protect the swapping of buffers
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* when taking a max snapshot. The buffers themselves are
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* protected by per_cpu spinlocks. But the action of the swap
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* needs its own lock.
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*
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* This is defined as a raw_spinlock_t in order to help
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* with performance when lockdep debugging is enabled.
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*
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* It is also used in other places outside the update_max_tr
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* so it needs to be defined outside of the
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* CONFIG_TRACER_MAX_TRACE.
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*/
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static raw_spinlock_t ftrace_max_lock =
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(raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
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#ifdef CONFIG_TRACER_MAX_TRACE
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unsigned long __read_mostly tracing_max_latency;
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unsigned long __read_mostly tracing_thresh;
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/*
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* Copy the new maximum trace into the separate maximum-trace
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* structure. (this way the maximum trace is permanently saved,
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* for later retrieval via /sys/kernel/debug/tracing/latency_trace)
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*/
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static void
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__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
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{
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struct trace_array_cpu *data = tr->data[cpu];
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max_tr.cpu = cpu;
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max_tr.time_start = data->preempt_timestamp;
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data = max_tr.data[cpu];
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data->saved_latency = tracing_max_latency;
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memcpy(data->comm, tsk->comm, TASK_COMM_LEN);
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data->pid = tsk->pid;
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data->uid = task_uid(tsk);
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data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
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data->policy = tsk->policy;
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data->rt_priority = tsk->rt_priority;
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/* record this tasks comm */
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tracing_record_cmdline(tsk);
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}
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/**
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* update_max_tr - snapshot all trace buffers from global_trace to max_tr
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* @tr: tracer
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@ -476,6 +481,7 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
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__update_max_tr(tr, tsk, cpu);
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__raw_spin_unlock(&ftrace_max_lock);
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}
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#endif /* CONFIG_TRACER_MAX_TRACE */
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/**
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* register_tracer - register a tracer with the ftrace system.
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@ -3952,11 +3958,13 @@ static __init int tracer_init_debugfs(void)
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trace_create_file("current_tracer", 0644, d_tracer,
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&global_trace, &set_tracer_fops);
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#ifdef CONFIG_TRACER_MAX_TRACE
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trace_create_file("tracing_max_latency", 0644, d_tracer,
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&tracing_max_latency, &tracing_max_lat_fops);
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trace_create_file("tracing_thresh", 0644, d_tracer,
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&tracing_thresh, &tracing_max_lat_fops);
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#endif
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trace_create_file("README", 0444, d_tracer,
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NULL, &tracing_readme_fops);
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@ -473,12 +473,14 @@ void unregister_tracer(struct tracer *type);
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extern unsigned long nsecs_to_usecs(unsigned long nsecs);
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#ifdef CONFIG_TRACER_MAX_TRACE
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extern unsigned long tracing_max_latency;
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extern unsigned long tracing_thresh;
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void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
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void update_max_tr_single(struct trace_array *tr,
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struct task_struct *tsk, int cpu);
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#endif /* CONFIG_TRACER_MAX_TRACE */
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#ifdef CONFIG_STACKTRACE
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void ftrace_trace_stack(struct trace_array *tr, unsigned long flags,
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