tracing/osnoise: Support a list of trace_array *tr
osnoise/timerlat were built to run a single instance, and for this, a single variable is enough to store the current struct trace_array *tr with information about the tracing instance. This is done via the *osnoise_trace variable. A trace_array represents a trace instance. In preparation to support multiple instances, replace the *osnoise_trace variable with an RCU protected list of instances. The operations that refer to an instance now propagate to all elements of the list (all instances). Also, replace the osnoise_busy variable with a check if the list has elements (busy). No functional change is expected with this patch, i.e., only one instance is allowed yet. Link: https://lkml.kernel.org/r/91d006e889b9a5d1ff258fe6077f021ae3f26372.1635702894.git.bristot@kernel.org Cc: Ingo Molnar <mingo@redhat.com> Cc: Tom Zanussi <zanussi@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Daniel Bristot de Oliveira
Steven Rostedt (VMware)
Родитель
2bd1bdf01f
Коммит
dae181349f
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@ -38,8 +38,6 @@
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#define CREATE_TRACE_POINTS
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#include <trace/events/osnoise.h>
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static struct trace_array *osnoise_trace;
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/*
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* Default values.
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*/
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@ -50,6 +48,81 @@ static struct trace_array *osnoise_trace;
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#define DEFAULT_TIMERLAT_PERIOD 1000 /* 1ms */
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#define DEFAULT_TIMERLAT_PRIO 95 /* FIFO 95 */
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/*
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* trace_array of the enabled osnoise/timerlat instances.
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*/
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struct osnoise_instance {
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struct list_head list;
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struct trace_array *tr;
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};
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struct list_head osnoise_instances;
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static bool osnoise_has_registered_instances(void)
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{
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return !!list_first_or_null_rcu(&osnoise_instances,
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struct osnoise_instance,
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list);
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}
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/*
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* osnoise_register_instance - register a new trace instance
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*
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* Register a trace_array *tr in the list of instances running
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* osnoise/timerlat tracers.
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*/
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static int osnoise_register_instance(struct trace_array *tr)
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{
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struct osnoise_instance *inst;
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/*
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* register/unregister serialization is provided by trace's
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* trace_types_lock.
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*/
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lockdep_assert_held(&trace_types_lock);
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inst = kmalloc(sizeof(*inst), GFP_KERNEL);
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if (!inst)
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return -ENOMEM;
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INIT_LIST_HEAD_RCU(&inst->list);
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inst->tr = tr;
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list_add_tail_rcu(&inst->list, &osnoise_instances);
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return 0;
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}
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/*
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* osnoise_unregister_instance - unregister a registered trace instance
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*
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* Remove the trace_array *tr from the list of instances running
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* osnoise/timerlat tracers.
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*/
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static void osnoise_unregister_instance(struct trace_array *tr)
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{
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struct osnoise_instance *inst;
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int found = 0;
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/*
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* register/unregister serialization is provided by trace's
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* trace_types_lock.
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*/
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lockdep_assert_held(&trace_types_lock);
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list_for_each_entry_rcu(inst, &osnoise_instances, list) {
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if (inst->tr == tr) {
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list_del_rcu(&inst->list);
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found = 1;
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break;
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}
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}
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if (!found)
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return;
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synchronize_rcu();
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kfree(inst);
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}
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/*
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* NMI runtime info.
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*/
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@ -248,11 +321,6 @@ static struct osnoise_data {
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#endif
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};
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/*
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* Boolean variable used to inform that the tracer is currently sampling.
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*/
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static bool osnoise_busy;
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#ifdef CONFIG_PREEMPT_RT
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/*
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* Print the osnoise header info.
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@ -315,19 +383,24 @@ static void print_osnoise_headers(struct seq_file *s)
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* osnoise_taint - report an osnoise error.
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*/
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#define osnoise_taint(msg) ({ \
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struct trace_array *tr = osnoise_trace; \
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struct osnoise_instance *inst; \
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struct trace_buffer *buffer; \
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\
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trace_array_printk_buf(tr->array_buffer.buffer, _THIS_IP_, msg); \
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rcu_read_lock(); \
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list_for_each_entry_rcu(inst, &osnoise_instances, list) { \
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buffer = inst->tr->array_buffer.buffer; \
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trace_array_printk_buf(buffer, _THIS_IP_, msg); \
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} \
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rcu_read_unlock(); \
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osnoise_data.tainted = true; \
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})
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/*
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* Record an osnoise_sample into the tracer buffer.
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*/
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static void trace_osnoise_sample(struct osnoise_sample *sample)
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static void
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__trace_osnoise_sample(struct osnoise_sample *sample, struct trace_buffer *buffer)
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{
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struct trace_array *tr = osnoise_trace;
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struct trace_buffer *buffer = tr->array_buffer.buffer;
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struct trace_event_call *call = &event_osnoise;
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struct ring_buffer_event *event;
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struct osnoise_entry *entry;
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@ -350,6 +423,22 @@ static void trace_osnoise_sample(struct osnoise_sample *sample)
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trace_buffer_unlock_commit_nostack(buffer, event);
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}
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/*
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* Record an osnoise_sample on all osnoise instances.
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*/
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static void trace_osnoise_sample(struct osnoise_sample *sample)
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{
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struct osnoise_instance *inst;
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struct trace_buffer *buffer;
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rcu_read_lock();
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list_for_each_entry_rcu(inst, &osnoise_instances, list) {
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buffer = inst->tr->array_buffer.buffer;
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__trace_osnoise_sample(sample, buffer);
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}
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rcu_read_unlock();
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}
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#ifdef CONFIG_TIMERLAT_TRACER
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/*
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* Print the timerlat header info.
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@ -388,14 +477,10 @@ static void print_timerlat_headers(struct seq_file *s)
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}
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#endif /* CONFIG_PREEMPT_RT */
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/*
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* Record an timerlat_sample into the tracer buffer.
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*/
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static void trace_timerlat_sample(struct timerlat_sample *sample)
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static void
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__trace_timerlat_sample(struct timerlat_sample *sample, struct trace_buffer *buffer)
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{
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struct trace_array *tr = osnoise_trace;
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struct trace_event_call *call = &event_osnoise;
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struct trace_buffer *buffer = tr->array_buffer.buffer;
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struct ring_buffer_event *event;
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struct timerlat_entry *entry;
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@ -412,6 +497,22 @@ static void trace_timerlat_sample(struct timerlat_sample *sample)
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trace_buffer_unlock_commit_nostack(buffer, event);
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}
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/*
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* Record an timerlat_sample into the tracer buffer.
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*/
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static void trace_timerlat_sample(struct timerlat_sample *sample)
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{
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struct osnoise_instance *inst;
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struct trace_buffer *buffer;
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rcu_read_lock();
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list_for_each_entry_rcu(inst, &osnoise_instances, list) {
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buffer = inst->tr->array_buffer.buffer;
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__trace_timerlat_sample(sample, buffer);
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}
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rcu_read_unlock();
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}
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#ifdef CONFIG_STACKTRACE
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#define MAX_CALLS 256
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@ -451,29 +552,18 @@ static void timerlat_save_stack(int skip)
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return;
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}
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/*
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* timerlat_dump_stack - dump a stack trace previously saved
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*
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* Dump a saved stack trace into the trace buffer.
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*/
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static void timerlat_dump_stack(void)
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static void
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__timerlat_dump_stack(struct trace_buffer *buffer, struct trace_stack *fstack, unsigned int size)
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{
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struct trace_event_call *call = &event_osnoise;
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struct trace_array *tr = osnoise_trace;
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struct trace_buffer *buffer = tr->array_buffer.buffer;
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struct ring_buffer_event *event;
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struct trace_stack *fstack;
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struct stack_entry *entry;
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unsigned int size;
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preempt_disable_notrace();
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fstack = this_cpu_ptr(&trace_stack);
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size = fstack->stack_size;
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event = trace_buffer_lock_reserve(buffer, TRACE_STACK, sizeof(*entry) + size,
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tracing_gen_ctx());
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if (!event)
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goto out;
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return;
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entry = ring_buffer_event_data(event);
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@ -482,8 +572,29 @@ static void timerlat_dump_stack(void)
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if (!call_filter_check_discard(call, entry, buffer, event))
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trace_buffer_unlock_commit_nostack(buffer, event);
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}
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out:
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/*
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* timerlat_dump_stack - dump a stack trace previously saved
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*/
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static void timerlat_dump_stack(void)
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{
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struct osnoise_instance *inst;
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struct trace_buffer *buffer;
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struct trace_stack *fstack;
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unsigned int size;
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preempt_disable_notrace();
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fstack = this_cpu_ptr(&trace_stack);
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size = fstack->stack_size;
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rcu_read_lock();
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list_for_each_entry_rcu(inst, &osnoise_instances, list) {
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buffer = inst->tr->array_buffer.buffer;
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__timerlat_dump_stack(buffer, fstack, size);
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}
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rcu_read_unlock();
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preempt_enable_notrace();
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}
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#else
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@ -1078,12 +1189,37 @@ diff_osn_sample_stats(struct osnoise_variables *osn_var, struct osnoise_sample *
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*/
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static __always_inline void osnoise_stop_tracing(void)
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{
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struct trace_array *tr = osnoise_trace;
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struct osnoise_instance *inst;
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struct trace_array *tr;
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trace_array_printk_buf(tr->array_buffer.buffer, _THIS_IP_,
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"stop tracing hit on cpu %d\n", smp_processor_id());
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rcu_read_lock();
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list_for_each_entry_rcu(inst, &osnoise_instances, list) {
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tr = inst->tr;
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trace_array_printk_buf(tr->array_buffer.buffer, _THIS_IP_,
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"stop tracing hit on cpu %d\n", smp_processor_id());
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tracer_tracing_off(tr);
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tracer_tracing_off(tr);
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}
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rcu_read_unlock();
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}
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/*
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* notify_new_max_latency - Notify a new max latency via fsnotify interface.
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*/
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static void notify_new_max_latency(u64 latency)
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{
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struct osnoise_instance *inst;
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struct trace_array *tr;
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rcu_read_lock();
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list_for_each_entry_rcu(inst, &osnoise_instances, list) {
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tr = inst->tr;
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if (tr->max_latency < latency) {
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tr->max_latency = latency;
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latency_fsnotify(tr);
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}
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}
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rcu_read_unlock();
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}
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/*
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@ -1097,7 +1233,6 @@ static __always_inline void osnoise_stop_tracing(void)
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static int run_osnoise(void)
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{
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struct osnoise_variables *osn_var = this_cpu_osn_var();
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struct trace_array *tr = osnoise_trace;
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u64 start, sample, last_sample;
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u64 last_int_count, int_count;
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s64 noise = 0, max_noise = 0;
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@ -1232,11 +1367,7 @@ static int run_osnoise(void)
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trace_osnoise_sample(&s);
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/* Keep a running maximum ever recorded osnoise "latency" */
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if (max_noise > tr->max_latency) {
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tr->max_latency = max_noise;
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latency_fsnotify(tr);
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}
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notify_new_max_latency(max_noise);
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if (osnoise_data.stop_tracing_total)
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if (s.noise > osnoise_data.stop_tracing_total)
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@ -1294,7 +1425,6 @@ static int osnoise_main(void *data)
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static enum hrtimer_restart timerlat_irq(struct hrtimer *timer)
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{
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struct osnoise_variables *osn_var = this_cpu_osn_var();
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struct trace_array *tr = osnoise_trace;
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struct timerlat_variables *tlat;
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struct timerlat_sample s;
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u64 now;
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@ -1365,11 +1495,7 @@ static enum hrtimer_restart timerlat_irq(struct hrtimer *timer)
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trace_timerlat_sample(&s);
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/* Keep a running maximum ever recorded os noise "latency" */
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if (diff > tr->max_latency) {
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tr->max_latency = diff;
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latency_fsnotify(tr);
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}
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notify_new_max_latency(diff);
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if (osnoise_data.stop_tracing)
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if (time_to_us(diff) >= osnoise_data.stop_tracing)
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@ -1581,7 +1707,7 @@ static void osnoise_hotplug_workfn(struct work_struct *dummy)
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mutex_lock(&trace_types_lock);
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if (!osnoise_busy)
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if (!osnoise_has_registered_instances())
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goto out_unlock_trace;
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mutex_lock(&interface_lock);
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@ -1716,11 +1842,10 @@ osnoise_cpus_write(struct file *filp, const char __user *ubuf, size_t count,
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goto err_free;
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/*
|
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* trace_types_lock is taken to avoid concurrency on start/stop
|
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* and osnoise_busy.
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* trace_types_lock is taken to avoid concurrency on start/stop.
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*/
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mutex_lock(&trace_types_lock);
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running = osnoise_busy;
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running = osnoise_has_registered_instances();
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if (running)
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stop_per_cpu_kthreads();
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|
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@ -1943,8 +2068,6 @@ static int osnoise_workload_start(void)
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return retval;
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}
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osnoise_busy = true;
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return 0;
|
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}
|
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|
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|
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@ -1953,7 +2076,7 @@ static int osnoise_workload_start(void)
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|||
*/
|
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static void osnoise_workload_stop(void)
|
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{
|
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if (!osnoise_busy)
|
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if (osnoise_has_registered_instances())
|
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return;
|
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|
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trace_osnoise_callback_enabled = false;
|
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|
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@ -1968,28 +2091,28 @@ static void osnoise_workload_stop(void)
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unhook_irq_events();
|
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unhook_softirq_events();
|
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unhook_thread_events();
|
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|
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osnoise_busy = false;
|
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}
|
||||
|
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static void osnoise_tracer_start(struct trace_array *tr)
|
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{
|
||||
int retval;
|
||||
|
||||
if (osnoise_busy)
|
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if (osnoise_has_registered_instances())
|
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return;
|
||||
|
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retval = osnoise_workload_start();
|
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if (retval)
|
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pr_err(BANNER "Error starting osnoise tracer\n");
|
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|
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osnoise_register_instance(tr);
|
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}
|
||||
|
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static void osnoise_tracer_stop(struct trace_array *tr)
|
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{
|
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if (!osnoise_busy)
|
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if (!osnoise_has_registered_instances())
|
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return;
|
||||
|
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osnoise_unregister_instance(tr);
|
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osnoise_workload_stop();
|
||||
}
|
||||
|
||||
|
|
@ -1997,14 +2120,12 @@ static int osnoise_tracer_init(struct trace_array *tr)
|
|||
{
|
||||
|
||||
/* Only allow one instance to enable this */
|
||||
if (osnoise_busy)
|
||||
if (osnoise_has_registered_instances())
|
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return -EBUSY;
|
||||
|
||||
osnoise_trace = tr;
|
||||
tr->max_latency = 0;
|
||||
|
||||
osnoise_tracer_start(tr);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
|
@ -2028,7 +2149,7 @@ static void timerlat_tracer_start(struct trace_array *tr)
|
|||
{
|
||||
int retval;
|
||||
|
||||
if (osnoise_busy)
|
||||
if (osnoise_has_registered_instances())
|
||||
return;
|
||||
|
||||
osnoise_data.timerlat_tracer = 1;
|
||||
|
|
@ -2037,6 +2158,8 @@ static void timerlat_tracer_start(struct trace_array *tr)
|
|||
if (retval)
|
||||
goto out_err;
|
||||
|
||||
osnoise_register_instance(tr);
|
||||
|
||||
return;
|
||||
out_err:
|
||||
pr_err(BANNER "Error starting timerlat tracer\n");
|
||||
|
|
@ -2046,7 +2169,7 @@ static void timerlat_tracer_stop(struct trace_array *tr)
|
|||
{
|
||||
int cpu;
|
||||
|
||||
if (!osnoise_busy)
|
||||
if (!osnoise_has_registered_instances())
|
||||
return;
|
||||
|
||||
for_each_online_cpu(cpu)
|
||||
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@ -2060,11 +2183,9 @@ static void timerlat_tracer_stop(struct trace_array *tr)
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static int timerlat_tracer_init(struct trace_array *tr)
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{
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/* Only allow one instance to enable this */
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if (osnoise_busy)
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if (osnoise_has_registered_instances())
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return -EBUSY;
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osnoise_trace = tr;
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tr->max_latency = 0;
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timerlat_tracer_start(tr);
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@ -2111,6 +2232,8 @@ __init static int init_osnoise_tracer(void)
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#endif
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osnoise_init_hotplug_support();
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INIT_LIST_HEAD_RCU(&osnoise_instances);
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||||
init_tracefs();
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||||
|
||||
return 0;
|
||||
|
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