ring_buffer_alloc
buffer = ring_buffer_alloc(RB_TEST_BUFFER_SIZE, RB_FL_OVERWRITE);
buffer = ring_buffer_alloc(1000000, RB_FL_OVERWRITE);
buf->buffer = ring_buffer_alloc(size, rb_flags);
temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);