RB_FL_OVERWRITE
buffer->flags |= RB_FL_OVERWRITE;
buffer->flags &= ~RB_FL_OVERWRITE;
if (!(buffer->flags & RB_FL_OVERWRITE)) {
buffer = ring_buffer_alloc(RB_TEST_BUFFER_SIZE, RB_FL_OVERWRITE);
buffer = ring_buffer_alloc(1000000, RB_FL_OVERWRITE);
temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
rb_flags = tr->trace_flags & TRACE_ITER(OVERWRITE) ? RB_FL_OVERWRITE : 0;