Merge 5495b55ab2 into 6592bffc60

* Add phi_2 solver type to seeds_2

* Add sampler node of seeds_2

comfy/k_diffusion/sampling.py

@@ -1557,10 +1557,13 @@ def sample_er_sde(model, x, sigmas, extra_args=None, callback=None, disable=None
 
 
 @torch.no_grad()
-def sample_seeds_2(model, x, sigmas, extra_args=None, callback=None, disable=None, eta=1., s_noise=1., noise_sampler=None, r=0.5):
+def sample_seeds_2(model, x, sigmas, extra_args=None, callback=None, disable=None, eta=1., s_noise=1., noise_sampler=None, r=0.5, solver_type="phi_1"):
     """SEEDS-2 - Stochastic Explicit Exponential Derivative-free Solvers (VP Data Prediction) stage 2.
     arXiv: https://arxiv.org/abs/2305.14267 (NeurIPS 2023)
     """
+    if solver_type not in {"phi_1", "phi_2"}:
+        raise ValueError("solver_type must be 'phi_1' or 'phi_2'")
+
     extra_args = {} if extra_args is None else extra_args
     seed = extra_args.get("seed", None)
     noise_sampler = default_noise_sampler(x, seed=seed) if noise_sampler is None else noise_sampler
@@ -1600,8 +1603,14 @@ def sample_seeds_2(model, x, sigmas, extra_args=None, callback=None, disable=Non
         denoised_2 = model(x_2, sigma_s_1 * s_in, **extra_args)
 
         # Step 2
-        denoised_d = torch.lerp(denoised, denoised_2, fac)
-        x = sigmas[i + 1] / sigmas[i] * (-h * eta).exp() * x - alpha_t * ei_h_phi_1(-h_eta) * denoised_d
+        if solver_type == "phi_1":
+            denoised_d = torch.lerp(denoised, denoised_2, fac)
+            x = sigmas[i + 1] / sigmas[i] * (-h * eta).exp() * x - alpha_t * ei_h_phi_1(-h_eta) * denoised_d
+        elif solver_type == "phi_2":
+            b2 = ei_h_phi_2(-h_eta) / r
+            b1 = ei_h_phi_1(-h_eta) - b2
+            x = sigmas[i + 1] / sigmas[i] * (-h * eta).exp() * x - alpha_t * (b1 * denoised + b2 * denoised_2)
+
         if inject_noise:
             segment_factor = (r - 1) * h * eta
             sde_noise = sde_noise * segment_factor.exp()

comfy/model_management.py

@@ -26,6 +26,18 @@ import importlib
 import platform
 import weakref
 import gc
+import os
+
+from functools import lru_cache
+
+@lru_cache(maxsize=1)
+def get_mmap_mem_threshold_gb():
+    mmap_mem_threshold_gb = int(os.environ.get("MMAP_MEM_THRESHOLD_GB", "0"))
+    logging.debug(f"MMAP_MEM_THRESHOLD_GB: {mmap_mem_threshold_gb}")
+    return mmap_mem_threshold_gb
+
+def get_free_disk():
+    return psutil.disk_usage("/").free
 
 class VRAMState(Enum):
     DISABLED = 0    #No vram present: no need to move models to vram
@@ -521,16 +533,33 @@ class LoadedModel:
         return False
 
     def model_unload(self, memory_to_free=None, unpatch_weights=True):
-        if memory_to_free is not None:
-            if memory_to_free < self.model.loaded_size():
-                freed = self.model.partially_unload(self.model.offload_device, memory_to_free)
-                if freed >= memory_to_free:
-                    return False
-        self.model.detach(unpatch_weights)
-        self.model_finalizer.detach()
-        self.model_finalizer = None
-        self.real_model = None
-        return True
+        if memory_to_free is None:
+            # free the full model
+            memory_to_free = self.model.loaded_size()
+
+        available_memory = get_free_memory(self.model.offload_device)
+
+        mmap_mem_threshold = get_mmap_mem_threshold_gb() * 1024 * 1024 * 1024  # this is reserved memory for other system usage
+        if memory_to_free > available_memory - mmap_mem_threshold or memory_to_free < self.model.loaded_size():
+            partially_unload = True
+        else:
+            partially_unload = False
+
+        if partially_unload:
+            freed = self.model.partially_unload(self.model.offload_device, memory_to_free)
+            if freed < memory_to_free:
+                logging.debug(f"Partially unload not enough memory, freed {freed/(1024*1024*1024)} GB, memory_to_free {memory_to_free/(1024*1024*1024)} GB")
+        else:
+            self.model.detach(unpatch_weights)
+            self.model_finalizer.detach()
+            self.model_finalizer = None
+            self.real_model = None
+
+        if partially_unload:
+            return False
+        else:
+            return True
+
 
     def model_use_more_vram(self, extra_memory, force_patch_weights=False):
         return self.model.partially_load(self.device, extra_memory, force_patch_weights=force_patch_weights)

comfy/model_patcher.py

@@ -27,6 +27,10 @@ import uuid
 from typing import Callable, Optional
 
 import torch
+import os
+import tempfile
+import weakref
+import gc
 
 import comfy.float
 import comfy.hooks
@@ -37,6 +41,76 @@ import comfy.utils
 from comfy.comfy_types import UnetWrapperFunction
 from comfy.quant_ops import QuantizedTensor
 from comfy.patcher_extension import CallbacksMP, PatcherInjection, WrappersMP
+from comfy.model_management import get_free_memory, get_mmap_mem_threshold_gb, get_free_disk
+from comfy.quant_ops import QuantizedTensor
+
+def need_mmap() -> bool:
+    free_cpu_mem = get_free_memory(torch.device("cpu"))
+    mmap_mem_threshold_gb = get_mmap_mem_threshold_gb()
+    if free_cpu_mem < mmap_mem_threshold_gb * 1024 * 1024 * 1024:
+        logging.debug(f"Enabling mmap, current free cpu memory {free_cpu_mem/(1024*1024*1024)} GB < {mmap_mem_threshold_gb} GB")
+        return True
+    return False
+
+def to_mmap(t: torch.Tensor, filename: Optional[str] = None) -> torch.Tensor:
+    """
+    Convert a tensor to a memory-mapped CPU tensor using PyTorch's native mmap support.
+    """
+    # Create temporary file
+    if filename is None:
+        temp_file = tempfile.mkstemp(suffix='.pt', prefix='comfy_mmap_')[1]
+    else:
+        temp_file = filename
+    
+    # Save tensor to file
+    cpu_tensor = t.cpu()
+    torch.save(cpu_tensor, temp_file)
+    
+    # If we created a CPU copy from other device, delete it to free memory
+    if not t.device.type == 'cpu':
+        del cpu_tensor
+        gc.collect()
+    
+    # Load with mmap - this doesn't load all data into RAM
+    mmap_tensor = torch.load(temp_file, map_location='cpu', mmap=True, weights_only=False)
+    
+    # Register cleanup callback - will be called when tensor is garbage collected
+    def _cleanup():
+        try:
+            if os.path.exists(temp_file):
+                os.remove(temp_file)
+                logging.debug(f"Cleaned up mmap file: {temp_file}")
+        except Exception:
+            pass
+    
+    weakref.finalize(mmap_tensor, _cleanup)
+
+    return mmap_tensor
+                
+def model_to_mmap(model: torch.nn.Module):
+    """Convert all parameters and buffers to memory-mapped tensors
+    
+    Args:
+        model: PyTorch module to convert
+        
+    Returns:
+        The same model with all tensors converted to memory-mapped format
+    """
+    free_cpu_mem = get_free_memory(torch.device("cpu"))
+    logging.debug(f"Converting model {model.__class__.__name__} to mmap, current free cpu memory: {free_cpu_mem/(1024*1024*1024)} GB")
+    
+    def convert_fn(t):
+        if isinstance(t, torch.nn.Parameter):
+            new_tensor = to_mmap(t.detach())
+            return torch.nn.Parameter(new_tensor, requires_grad=t.requires_grad)
+        elif isinstance(t, torch.Tensor):
+            return to_mmap(t)
+        return t
+    
+    new_model = model._apply(convert_fn)
+    free_cpu_mem = get_free_memory(torch.device("cpu"))
+    logging.debug(f"Model {model.__class__.__name__} converted to mmap, current free cpu memory: {free_cpu_mem/(1024*1024*1024)} GB")
+    return new_model
 
 
 def string_to_seed(data):
@@ -506,6 +580,7 @@ class ModelPatcher:
                 return comfy.utils.get_attr(self.model, name)
 
     def model_patches_to(self, device):
+        # TODO(sf): to mmap
         to = self.model_options["transformer_options"]
         if "patches" in to:
             patches = to["patches"]
@@ -853,9 +928,15 @@ class ModelPatcher:
             self.model.current_weight_patches_uuid = None
             self.backup.clear()
 
+                
             if device_to is not None:
-                self.model.to(device_to)
+                if need_mmap():
+                    # offload to mmap
+                    model_to_mmap(self.model)
+                else:
+                    self.model.to(device_to)
                 self.model.device = device_to
+            
             self.model.model_loaded_weight_memory = 0
             self.model.model_offload_buffer_memory = 0
 
@@ -914,7 +995,14 @@ class ModelPatcher:
                     bias_key = "{}.bias".format(n)
                     if move_weight:
                         cast_weight = self.force_cast_weights
-                        m.to(device_to)
+                        if need_mmap():
+                            if get_free_disk() < module_mem:
+                                logging.warning(f"Not enough disk space to offload {n} to mmap, current free disk space {get_free_disk()/(1024*1024*1024)} GB < {module_mem/(1024*1024*1024)} GB")
+                                break
+                            # offload to mmap
+                            model_to_mmap(m)
+                        else:
+                            m.to(device_to)
                         module_mem += move_weight_functions(m, device_to)
                         if lowvram_possible:
                             if weight_key in self.patches:

comfy/quant_ops.py

@@ -130,7 +130,19 @@ class QuantizedTensor(torch.Tensor):
             layout_type: Layout class (subclass of QuantizedLayout)
             layout_params: Dict with layout-specific parameters
         """
-        return torch.Tensor._make_wrapper_subclass(cls, qdata.shape, device=qdata.device, dtype=qdata.dtype, requires_grad=False)
+        # Use as_subclass so the QuantizedTensor instance shares the same
+        # storage and metadata as the underlying qdata tensor. This ensures
+        # torch.save/torch.load and the torch serialization storage scanning
+        # see a valid underlying storage (fixes data_ptr errors).
+        if not isinstance(qdata, torch.Tensor):
+            raise TypeError("qdata must be a torch.Tensor")
+        obj = qdata.as_subclass(cls)
+        # Ensure grad flag is consistent for quantized tensors
+        try:
+            obj.requires_grad_(False)
+        except Exception:
+            pass
+        return obj
 
     def __init__(self, qdata, layout_type, layout_params):
         self._qdata = qdata
@@ -578,3 +590,34 @@ def fp8_func(func, args, kwargs):
         ar[0] = plain_input
         return QuantizedTensor(func(*ar, **kwargs), "TensorCoreFP8Layout", input_tensor._layout_params)
     return func(*args, **kwargs)
+
+def _rebuild_quantized_tensor(qdata, layout_type, layout_params):
+    """Rebuild QuantizedTensor during unpickling when qdata is already a tensor."""
+    return QuantizedTensor(qdata, layout_type, layout_params)
+
+
+def _rebuild_quantized_tensor_from_base(qdata_reduce, layout_type, layout_params):
+    """Rebuild QuantizedTensor during unpickling given the base tensor's reduce tuple.
+
+    qdata_reduce is the tuple returned by qdata.__reduce_ex__(protocol) on the original
+    inner tensor. We call the provided rebuild function with its args to recreate the
+    inner tensor, then wrap it in QuantizedTensor.
+    """
+    rebuild_fn, rebuild_args = qdata_reduce
+    qdata = rebuild_fn(*rebuild_args)
+    return QuantizedTensor(qdata, layout_type, layout_params)
+
+
+# Register custom globals with torch.serialization so torch.load(..., weights_only=True)
+# accepts these during unpickling. Wrapped in try/except for older PyTorch versions.
+try:
+    import torch as _torch_serial
+    if hasattr(_torch_serial, "serialization") and hasattr(_torch_serial.serialization, "add_safe_globals"):
+        _torch_serial.serialization.add_safe_globals([
+            QuantizedTensor,
+            _rebuild_quantized_tensor,
+            _rebuild_quantized_tensor_from_base,
+        ])
+except Exception:
+    # If add_safe_globals doesn't exist or registration fails, we silently continue.
+    pass

comfy_extras/nodes_custom_sampler.py

@@ -659,6 +659,31 @@ class SamplerSASolver(io.ComfyNode):
     get_sampler = execute
 
 
+class SamplerSEEDS2(io.ComfyNode):
+    @classmethod
+    def define_schema(cls):
+        return io.Schema(
+            node_id="SamplerSEEDS2",
+            category="sampling/custom_sampling/samplers",
+            inputs=[
+                io.Combo.Input("solver_type", options=["phi_1", "phi_2"]),
+                io.Float.Input("eta", default=1.0, min=0.0, max=100.0, step=0.01, round=False, tooltip="Stochastic strength"),
+                io.Float.Input("s_noise", default=1.0, min=0.0, max=100.0, step=0.01, round=False, tooltip="SDE noise multiplier"),
+                io.Float.Input("r", default=0.5, min=0.01, max=1.0, step=0.01, round=False, tooltip="Relative step size for the intermediate stage (c2 node)"),
+            ],
+            outputs=[io.Sampler.Output()]
+        )
+
+    @classmethod
+    def execute(cls, solver_type, eta, s_noise, r) -> io.NodeOutput:
+        sampler_name = "seeds_2"
+        sampler = comfy.samplers.ksampler(
+            sampler_name,
+            {"eta": eta, "s_noise": s_noise, "r": r, "solver_type": solver_type},
+        )
+        return io.NodeOutput(sampler)
+
+
 class Noise_EmptyNoise:
     def __init__(self):
         self.seed = 0
@@ -996,6 +1021,7 @@ class CustomSamplersExtension(ComfyExtension):
             SamplerDPMAdaptative,
             SamplerER_SDE,
             SamplerSASolver,
+            SamplerSEEDS2,
             SplitSigmas,
             SplitSigmasDenoise,
             FlipSigmas,

tests-unit/comfy_quant/test_quant_registry.py

@@ -47,6 +47,29 @@ class TestQuantizedTensor(unittest.TestCase):
         self.assertEqual(dequantized.dtype, torch.float32)
         self.assertTrue(torch.allclose(dequantized, torch.ones(10, 20) * 3.0, rtol=0.1))
 
+    def test_save_load(self):
+        """Test creating a QuantizedTensor with TensorCoreFP8Layout"""
+        fp8_data = torch.randn(256, 128, dtype=torch.float32).to(torch.float8_e4m3fn)
+        scale = torch.tensor(2.0)
+        layout_params = {'scale': scale, 'orig_dtype': torch.bfloat16}
+
+        qt = QuantizedTensor(fp8_data, "TensorCoreFP8Layout", layout_params)
+
+        self.assertIsInstance(qt, QuantizedTensor)
+        self.assertEqual(qt.shape, (256, 128))
+        self.assertEqual(qt.dtype, torch.float8_e4m3fn)
+        self.assertEqual(qt._layout_params['scale'], scale)
+        self.assertEqual(qt._layout_params['orig_dtype'], torch.bfloat16)
+        self.assertEqual(qt._layout_type, "TensorCoreFP8Layout")
+
+        torch.save(qt, "test.pt")
+        loaded_qt = torch.load("test.pt", weights_only=False)
+        # loaded_qt = torch.load("test.pt", map_location='cpu', mmap=True, weights_only=False)
+
+        self.assertEqual(loaded_qt._layout_type, "TensorCoreFP8Layout")
+        self.assertEqual(loaded_qt._layout_params['scale'], scale)
+        self.assertEqual(loaded_qt._layout_params['orig_dtype'], torch.bfloat16)
+
     def test_from_float(self):
         """Test creating QuantizedTensor from float tensor"""
         float_tensor = torch.randn(64, 32, dtype=torch.float32)

tests/inference/test_model_mmap.py

@@ -0,0 +1,287 @@
+import pytest
+import torch
+import torch.nn as nn
+import psutil
+import os
+import gc
+import tempfile
+import sys
+
+# Ensure the project root is on the Python path (so `import comfy` works when running tests from this folder)
+sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '..', '..')))
+
+from comfy.model_patcher import model_to_mmap, to_mmap
+
+
+class LargeModel(nn.Module):
+    """A simple model with large parameters for testing memory mapping"""
+    
+    def __init__(self, size_gb=10):
+        super().__init__()
+        # Calculate number of float32 elements needed for target size
+        # 1 GB = 1024^3 bytes, float32 = 4 bytes
+        bytes_per_gb = 1024 * 1024 * 1024
+        elements_per_gb = bytes_per_gb // 4  # float32 is 4 bytes
+        total_elements = int(size_gb * elements_per_gb)
+        
+        # Create a large linear layer
+        # Split into multiple layers to avoid single tensor size limits
+        self.layers = nn.ModuleList()
+        elements_per_layer = 500 * 1024 * 1024  # 500M elements per layer (~2GB)
+        num_layers = (total_elements + elements_per_layer - 1) // elements_per_layer
+        
+        for i in range(num_layers):
+            if i == num_layers - 1:
+                # Last layer gets the remaining elements
+                remaining = total_elements - (i * elements_per_layer)
+                in_features = int(remaining ** 0.5)
+                out_features = (remaining + in_features - 1) // in_features
+            else:
+                in_features = int(elements_per_layer ** 0.5)
+                out_features = (elements_per_layer + in_features - 1) // in_features
+            
+            # Create layer without bias to control size precisely
+            self.layers.append(nn.Linear(in_features, out_features, bias=False))
+    
+    def forward(self, x):
+        for layer in self.layers:
+            x = layer(x)
+        return x
+
+
+def get_process_memory_gb():
+    """Get current process memory usage in GB"""
+    process = psutil.Process(os.getpid())
+    mem_info = process.memory_info()
+    return mem_info.rss / (1024 ** 3)  # Convert to GB
+
+
+def get_model_size_gb(model):
+    """Calculate model size in GB"""
+    total_size = 0
+    for param in model.parameters():
+        total_size += param.nelement() * param.element_size()
+    for buffer in model.buffers():
+        total_size += buffer.nelement() * buffer.element_size()
+    return total_size / (1024 ** 3)
+
+
+def test_model_to_mmap_memory_efficiency():
+    """Test that model_to_mmap reduces memory usage for a 10GB model to less than 1GB
+    
+    The typical use case is:
+    1. Load a large model on CUDA
+    2. Convert to mmap to offload from GPU to disk-backed memory
+    3. This frees GPU memory and reduces CPU RAM usage
+    """
+    
+    # Check if CUDA is available
+    if not torch.cuda.is_available():
+        pytest.skip("CUDA is not available, skipping test")
+    
+    # Force garbage collection before starting
+    gc.collect()
+    torch.cuda.empty_cache()
+    
+    # Record initial memory
+    initial_cpu_memory = get_process_memory_gb()
+    initial_gpu_memory = torch.cuda.memory_allocated() / (1024 ** 3)
+    print(f"\nInitial CPU memory: {initial_cpu_memory:.2f} GB")
+    print(f"Initial GPU memory: {initial_gpu_memory:.2f} GB")
+    
+    # Create a 10GB model
+    print("Creating 10GB model...")
+    model = LargeModel(size_gb=10)
+    
+    # Verify model size
+    model_size = get_model_size_gb(model)
+    print(f"Model size: {model_size:.2f} GB")
+    assert model_size >= 9.5, f"Model size {model_size:.2f} GB is less than expected 10 GB"
+    
+    # Move model to CUDA
+    print("Moving model to CUDA...")
+    model = model.cuda()
+    torch.cuda.synchronize()
+    
+    # Memory after moving to CUDA
+    cpu_after_cuda = get_process_memory_gb()
+    gpu_after_cuda = torch.cuda.memory_allocated() / (1024 ** 3)
+    print(f"CPU memory after moving to CUDA: {cpu_after_cuda:.2f} GB")
+    print(f"GPU memory after moving to CUDA: {gpu_after_cuda:.2f} GB")
+    
+    # Convert to mmap (this should move model from GPU to disk-backed memory)
+    # Note: model_to_mmap modifies the model in-place via _apply()
+    # so model and model_mmap will be the same object
+    print("Converting model to mmap...")
+    model_mmap = model_to_mmap(model)
+    
+    # Verify that model and model_mmap are the same object (in-place modification)
+    assert model is model_mmap, "model_to_mmap should modify the model in-place"
+    
+    # Force garbage collection and clear CUDA cache
+    # The original CUDA tensors should be automatically freed when replaced
+    gc.collect()
+    torch.cuda.empty_cache()
+    torch.cuda.synchronize()
+    
+    # Memory after mmap conversion
+    cpu_after_mmap = get_process_memory_gb()
+    gpu_after_mmap = torch.cuda.memory_allocated() / (1024 ** 3)
+    print(f"CPU memory after mmap: {cpu_after_mmap:.2f} GB")
+    print(f"GPU memory after mmap: {gpu_after_mmap:.2f} GB")
+    
+    # Calculate memory changes from CUDA state (the baseline we're converting from)
+    cpu_increase = cpu_after_mmap - cpu_after_cuda
+    gpu_decrease = gpu_after_cuda - gpu_after_mmap  # Should be positive (freed)
+    print(f"\nCPU memory increase from CUDA: {cpu_increase:.2f} GB")
+    print(f"GPU memory freed: {gpu_decrease:.2f} GB")
+    
+    # Verify that CPU memory usage increase is less than 1GB
+    # The mmap should use disk-backed storage, keeping CPU RAM usage low
+    # We use 1.5 GB threshold to account for overhead
+    assert cpu_increase < 1.5, (
+        f"CPU memory increase after mmap ({cpu_increase:.2f} GB) should be less than 1.5 GB. "
+        f"CUDA state: {cpu_after_cuda:.2f} GB, After mmap: {cpu_after_mmap:.2f} GB"
+    )
+    
+    # Verify that GPU memory has been freed
+    # We expect at least 9 GB to be freed (original 10GB model with some tolerance)
+    assert gpu_decrease > 9.0, (
+        f"GPU memory should be freed after mmap. "
+        f"Freed: {gpu_decrease:.2f} GB (from {gpu_after_cuda:.2f} to {gpu_after_mmap:.2f} GB), expected > 9 GB"
+    )
+    
+    # Verify the model is still functional (basic sanity check)
+    assert model_mmap is not None
+    assert len(list(model_mmap.parameters())) > 0
+    
+    print(f"\n✓ Test passed!")
+    print(f"  CPU memory increase: {cpu_increase:.2f} GB < 1.5 GB")
+    print(f"  GPU memory freed: {gpu_decrease:.2f} GB > 9.0 GB")
+    print(f"  Model successfully offloaded from GPU to disk-backed memory")
+    
+    # Cleanup (model and model_mmap are the same object)
+    del model, model_mmap
+    gc.collect()
+    torch.cuda.empty_cache()
+
+
+def test_to_mmap_cuda_cycle():
+    """Test CUDA -> mmap -> CUDA cycle
+    
+    This test verifies:
+    1. CUDA tensor can be converted to mmap tensor
+    2. CPU memory increase is minimal when using mmap (< 0.1 GB)
+    3. GPU memory is freed when converting to mmap
+    4. mmap tensor can be moved back to CUDA
+    5. Data remains consistent throughout the cycle
+    6. mmap file is automatically cleaned up via garbage collection
+    """
+    
+    # Check if CUDA is available
+    if not torch.cuda.is_available():
+        pytest.skip("CUDA is not available, skipping test")
+    
+    # Force garbage collection
+    gc.collect()
+    torch.cuda.empty_cache()
+    
+    print("\nTest: CUDA -> mmap -> CUDA cycle")
+    
+    # Record initial CPU memory
+    initial_cpu_memory = get_process_memory_gb()
+    print(f"Initial CPU memory: {initial_cpu_memory:.2f} GB")
+    
+    # Step 1: Create a CUDA tensor
+    print("\n1. Creating CUDA tensor...")
+    original_data = torch.randn(5000, 5000).cuda()
+    original_sum = original_data.sum().item()
+    print(f"   Shape: {original_data.shape}")
+    print(f"   Device: {original_data.device}")
+    print(f"   Sum: {original_sum:.2f}")
+    
+    # Record GPU and CPU memory after CUDA allocation
+    cpu_after_cuda = get_process_memory_gb()
+    gpu_before_mmap = torch.cuda.memory_allocated() / (1024 ** 3)
+    print(f"   GPU memory: {gpu_before_mmap:.2f} GB")
+    print(f"   CPU memory: {cpu_after_cuda:.2f} GB")
+    
+    # Step 2: Convert to mmap tensor
+    print("\n2. Converting to mmap tensor...")
+    mmap_tensor = to_mmap(original_data)
+    del original_data
+    gc.collect()
+    torch.cuda.empty_cache()
+    
+    print(f"   Device: {mmap_tensor.device}")
+    print(f"   Sum: {mmap_tensor.sum().item():.2f}")
+    
+    # Verify GPU memory is freed
+    gpu_after_mmap = torch.cuda.memory_allocated() / (1024 ** 3)
+    cpu_after_mmap = get_process_memory_gb()
+    print(f"   GPU memory freed: {gpu_before_mmap - gpu_after_mmap:.2f} GB")
+    print(f"   CPU memory: {cpu_after_mmap:.2f} GB")
+    
+    # Verify GPU memory is freed
+    assert gpu_after_mmap < 0.1, f"GPU memory should be freed, but {gpu_after_mmap:.2f} GB still allocated"
+    
+    # Verify CPU memory increase is minimal (should be close to 0 due to mmap)
+    cpu_increase = cpu_after_mmap - cpu_after_cuda
+    print(f"   CPU memory increase: {cpu_increase:.2f} GB")
+    assert cpu_increase < 0.1, f"CPU memory should increase minimally, but increased by {cpu_increase:.2f} GB"
+    
+    # Get the temp file path (we'll check if it gets cleaned up)
+    # The file should exist at this point
+    temp_files_before = len([f for f in os.listdir(tempfile.gettempdir()) if f.startswith('comfy_mmap_')])
+    print(f"   Temp mmap files exist: {temp_files_before}")
+    
+    # Step 3: Move back to CUDA
+    print("\n3. Moving back to CUDA...")
+    cuda_tensor = mmap_tensor.to('cuda')
+    torch.cuda.synchronize()
+    
+    print(f"   Device: {cuda_tensor.device}")
+    final_sum = cuda_tensor.sum().item()
+    print(f"   Sum: {final_sum:.2f}")
+    
+    # Verify GPU memory is used again
+    gpu_after_cuda = torch.cuda.memory_allocated() / (1024 ** 3)
+    print(f"   GPU memory: {gpu_after_cuda:.2f} GB")
+    
+    # Step 4: Verify data consistency
+    print("\n4. Verifying data consistency...")
+    sum_diff = abs(original_sum - final_sum)
+    print(f"   Original sum: {original_sum:.2f}")
+    print(f"   Final sum: {final_sum:.2f}")
+    print(f"   Difference: {sum_diff:.6f}")
+    assert sum_diff < 0.01, f"Data should be consistent, but difference is {sum_diff:.6f}"
+    
+    # Step 5: Verify file cleanup (delayed until garbage collection)
+    print("\n5. Verifying file cleanup...")
+    # Delete the mmap tensor reference to trigger garbage collection
+    del mmap_tensor
+    gc.collect()
+    import time
+    time.sleep(0.1)  # Give OS time to clean up
+    temp_files_after = len([f for f in os.listdir(tempfile.gettempdir()) if f.startswith('comfy_mmap_')])
+    print(f"   Temp mmap files after GC: {temp_files_after}")
+    # File should be cleaned up after garbage collection
+    assert temp_files_after <= temp_files_before, "mmap file should be cleaned up after garbage collection"
+    
+    print("\n✓ Test passed!")
+    print("  CUDA -> mmap -> CUDA cycle works correctly")
+    print(f"  CPU memory increase: {cpu_increase:.2f} GB < 0.1 GB (mmap efficiency)")
+    print("  Data consistency maintained")
+    print("  File cleanup successful (via garbage collection)")
+    
+    # Cleanup
+    del cuda_tensor  # mmap_tensor already deleted in Step 5
+    gc.collect()
+    torch.cuda.empty_cache()
+
+
+if __name__ == "__main__":
+    # Run the tests directly
+    test_model_to_mmap_memory_efficiency()
+    test_to_mmap_cuda_cycle()
+