def calc_padded_numel(shape: torch.Size, dtype: torch.dtype):
    """for cuda memory alignment, make sure alignment by 128-bits"""
    align_numel = 128 // torch.finfo(dtype).bits
    numel = shape.numel()
    return (numel + align_numel - 1) // align_numel * align_numel
for cuda memory alignment, make sure alignment by 128-bits
verl/utils/memory_buffer.py