• Stefan Hajnoczi's avatar
    trace: add trace_event_get_state_backends() · d87aa138
    Stefan Hajnoczi authored
    Code that checks dstate is unaware of SystemTap and LTTng UST dstate, so
    the following trace event will not fire when solely enabled by SystemTap
    or LTTng UST:
    
      if (trace_event_get_state(TRACE_MY_EVENT)) {
          str = g_strdup_printf("Expensive string to generate ...",
                                ...);
          trace_my_event(str);
          g_free(str);
      }
    
    Add trace_event_get_state_backends() to fetch backend dstate.  Those
    backends that use QEMU dstate fetch it as part of
    generate_h_backend_dstate().
    
    Update existing trace_event_get_state() callers to use
    trace_event_get_state_backends() instead.
    Signed-off-by: 's avatarStefan Hajnoczi <stefanha@redhat.com>
    Message-id: 20170731140718.22010-3-stefanha@redhat.com
    Signed-off-by: 's avatarStefan Hajnoczi <stefanha@redhat.com>
    d87aa138