tracing: install trace events file only if necessary

[mirror_qemu.git] / trace / control-target.c

/*
 * Interface for configuring and controlling the state of tracing events.
 *
 * Copyright (C) 2014-2017 Lluís Vilanova <vilanova@ac.upc.edu>
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or later.
 * See the COPYING file in the top-level directory.
 */

#include "qemu/osdep.h"
#include "qemu/lockable.h"
#include "cpu.h"
#include "trace/trace-root.h"
#include "trace/control.h"


void trace_event_set_state_dynamic_init(TraceEvent *ev, bool state)
{
    bool state_pre;
    assert(trace_event_get_state_static(ev));
    /*
     * We ignore the "vcpu" property here, since no vCPUs have been created
     * yet. Then dstate can only be 1 or 0.
     */
    state_pre = *ev->dstate;
    if (state_pre != state) {
        if (state) {
            trace_events_enabled_count++;
            *ev->dstate = 1;
        } else {
            trace_events_enabled_count--;
            *ev->dstate = 0;
        }
    }
}

void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
{
    assert(trace_event_get_state_static(ev));

    /*
     * There is no longer a "vcpu" property, dstate can only be 1 or
     * 0. With it, we haven't instantiated any vCPU yet, so we will
     * set a global state instead, and trace_init_vcpu will reconcile
     * it afterwards.
     */
    bool state_pre = *ev->dstate;
    if (state_pre != state) {
        if (state) {
            trace_events_enabled_count++;
            *ev->dstate = 1;
        } else {
            trace_events_enabled_count--;
            *ev->dstate = 0;
        }
    }
}