Function fill_slots_from_block_table 

pub fn fill_slots_from_block_table(
    gpu: &dyn GpuBackend,
    kernel: KernelHandle,
    slots: DevicePtr,
    block_table: DevicePtr,
    start_pos: u32,
    count: u32,
    block_size: u32,
    stream: u64,
) -> Result<()>

2026-09-25: Fill count slot-mapping entries on the device from a block table: slots[i] = block_table[(start_pos + i) / block_size] * block_size + (start_pos + i) % block_size. count == 0 launches nothing.