function trace(entry_p, extra) {
  %( $# > 1 %? if (tid() in trace) %)
  printf("%s%s%s %s\n",
         thread_indent (entry_p),
         (entry_p>0?"->":"<-"),
         ppfunc (),
         extra)
}
//probe module("nfs").function("*").call   { trace(1, $$parms) }
//probe module("nfs").function("*").return { trace(-1, $$return) }

probe module("vboxsf").function("*").call   { trace(1, $$parms) }
probe module("vboxsf").function("*").return { trace(-1, $$return) }

//probe module("ext4").function("*").call   { trace(1, $$parms) }
//probe module("ext4").function("*").return { trace(-1, $$return) }

//probe kernel.function("*@mm/filemap.c").call { trace(1, $$parms) }
//probe kernel.function("*@mm/filemap.c").return { trace(-1, $$return) }

probe kernel.function("*@mm/readahead.c").call { trace(1, $$parms) }
probe kernel.function("*@mm/readahead.c").return { trace(-1, $$return) }

probe kernel.function("generic_file_read_iter").call { trace(1, $$parms) }
probe kernel.function("generic_file_read_iter").return { trace(-1, $$return) }