tracing: Move ftrace_max_lock into trace_array
In preparation for having tracers enabled in instances, the max_lock
should be unique as updating the max for one tracer is a separate
operation than updating it for another tracer using a different max.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f5fc56b..bb5147a5 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -963,22 +963,6 @@
return cnt;
}
-/*
- * ftrace_max_lock is used to protect the swapping of buffers
- * when taking a max snapshot. The buffers themselves are
- * protected by per_cpu spinlocks. But the action of the swap
- * needs its own lock.
- *
- * This is defined as a arch_spinlock_t in order to help
- * with performance when lockdep debugging is enabled.
- *
- * It is also used in other places outside the update_max_tr
- * so it needs to be defined outside of the
- * CONFIG_TRACER_MAX_TRACE.
- */
-static arch_spinlock_t ftrace_max_lock =
- (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
-
unsigned long __read_mostly tracing_thresh;
#ifdef CONFIG_TRACER_MAX_TRACE
@@ -1046,14 +1030,14 @@
return;
}
- arch_spin_lock(&ftrace_max_lock);
+ arch_spin_lock(&tr->max_lock);
buf = tr->trace_buffer.buffer;
tr->trace_buffer.buffer = tr->max_buffer.buffer;
tr->max_buffer.buffer = buf;
__update_max_tr(tr, tsk, cpu);
- arch_spin_unlock(&ftrace_max_lock);
+ arch_spin_unlock(&tr->max_lock);
}
/**
@@ -1079,7 +1063,7 @@
return;
}
- arch_spin_lock(&ftrace_max_lock);
+ arch_spin_lock(&tr->max_lock);
ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->trace_buffer.buffer, cpu);
@@ -1097,7 +1081,7 @@
WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
__update_max_tr(tr, tsk, cpu);
- arch_spin_unlock(&ftrace_max_lock);
+ arch_spin_unlock(&tr->max_lock);
}
#endif /* CONFIG_TRACER_MAX_TRACE */
@@ -1351,7 +1335,7 @@
}
/* Prevent the buffers from switching */
- arch_spin_lock(&ftrace_max_lock);
+ arch_spin_lock(&global_trace.max_lock);
buffer = global_trace.trace_buffer.buffer;
if (buffer)
@@ -1363,7 +1347,7 @@
ring_buffer_record_enable(buffer);
#endif
- arch_spin_unlock(&ftrace_max_lock);
+ arch_spin_unlock(&global_trace.max_lock);
ftrace_start();
out:
@@ -1418,7 +1402,7 @@
goto out;
/* Prevent the buffers from switching */
- arch_spin_lock(&ftrace_max_lock);
+ arch_spin_lock(&global_trace.max_lock);
buffer = global_trace.trace_buffer.buffer;
if (buffer)
@@ -1430,7 +1414,7 @@
ring_buffer_record_disable(buffer);
#endif
- arch_spin_unlock(&ftrace_max_lock);
+ arch_spin_unlock(&global_trace.max_lock);
out:
raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
@@ -3331,7 +3315,7 @@
mutex_lock(&tracing_cpumask_update_lock);
local_irq_disable();
- arch_spin_lock(&ftrace_max_lock);
+ arch_spin_lock(&tr->max_lock);
for_each_tracing_cpu(cpu) {
/*
* Increase/decrease the disabled counter if we are
@@ -3348,7 +3332,7 @@
ring_buffer_record_enable_cpu(tr->trace_buffer.buffer, cpu);
}
}
- arch_spin_unlock(&ftrace_max_lock);
+ arch_spin_unlock(&tr->max_lock);
local_irq_enable();
cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
@@ -6129,6 +6113,8 @@
raw_spin_lock_init(&tr->start_lock);
+ tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+
tr->current_trace = &nop_trace;
INIT_LIST_HEAD(&tr->systems);
@@ -6627,6 +6613,8 @@
*/
global_trace.current_trace = &nop_trace;
+ global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+
ftrace_init_global_array_ops(&global_trace);
register_tracer(&nop_trace);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 644a8b5..5d2f07d 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -192,6 +192,20 @@
bool allocated_snapshot;
unsigned long max_latency;
#endif
+ /*
+ * max_lock is used to protect the swapping of buffers
+ * when taking a max snapshot. The buffers themselves are
+ * protected by per_cpu spinlocks. But the action of the swap
+ * needs its own lock.
+ *
+ * This is defined as a arch_spinlock_t in order to help
+ * with performance when lockdep debugging is enabled.
+ *
+ * It is also used in other places outside the update_max_tr
+ * so it needs to be defined outside of the
+ * CONFIG_TRACER_MAX_TRACE.
+ */
+ arch_spinlock_t max_lock;
int buffer_disabled;
#ifdef CONFIG_FTRACE_SYSCALLS
int sys_refcount_enter;
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index ac31858..1c95cd7 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -65,7 +65,7 @@
/* Don't allow flipping of max traces now */
local_irq_save(flags);
- arch_spin_lock(&ftrace_max_lock);
+ arch_spin_lock(&buf->tr->max_lock);
cnt = ring_buffer_entries(buf->buffer);
@@ -83,7 +83,7 @@
break;
}
tracing_on();
- arch_spin_unlock(&ftrace_max_lock);
+ arch_spin_unlock(&buf->tr->max_lock);
local_irq_restore(flags);
if (count)
