Files
smthemex-ComfyUI_UniBlockSwap/block_swap.py
T
Flakeforever ec21b19fb2 Fix block slicing access in UniBlockSwap
The block manager previously assumed all __getitem__ calls used integer indices. When a slice was used (e.g. blocks[start:end]), the slice object was incorrectly passed into swap logic, causing invalid comparisons and failures.
2026-08-05 08:53:08 -07:00

307 lines
10 KiB
Python

"""
UniBlockSwap - Universal single-block swap for ComfyUI.
Safetensor blocks: freed to meta on swap, restored by vbar automatically.
GGUF blocks: freed to CPU on swap, moved to GPU when accessed.
"""
import gc
import logging
import torch
import torch.nn as nn
logger = logging.getLogger(__name__)
CONTAINER_NAMES = (
"blocks", "transformer_blocks", "double_blocks", "single_blocks",
"input_blocks", "output_blocks", "middle_block", "layers",
"double_stream_layers", "single_stream_layers",
"block",
)
def find_blocks(model):
for name in CONTAINER_NAMES:
c = getattr(model, name, None)
if isinstance(c, (nn.ModuleList, list)) and len(c) > 0 and hasattr(c[0], "forward"):
return name, c
return None, None
def _has_ggml_params(module):
"""Check if module has GGMLTensor parameters (quantized GGUF weights)."""
for p in module.parameters():
if hasattr(p, 'tensor_type'):
return True
return False
def _free_to_meta(module):
"""Free param data to meta tensor - NO CPU copy created.
The module structure is preserved. next load() restores from backup."""
for param in module.parameters(recurse=False):
param.data = torch.empty(0, device='meta')
class SwappableModuleList(nn.ModuleList):
def __init__(self, modules, compute_device, offload_device,
non_swap_count=0):
super().__init__(modules)
self.compute_device = compute_device
self.offload_device = offload_device
self.non_swap_count = non_swap_count
self.total_count = len(modules)
self._loaded_swap_idx = -1
self.container_name = ''
def _load_swap(self, local_idx):
idx = local_idx + self.non_swap_count
if local_idx == self._loaded_swap_idx:
return
if self._loaded_swap_idx >= 0:
prev = self._loaded_swap_idx + self.non_swap_count
try:
# FREE previous block GPU memory
if _has_ggml_params(self._modules[str(prev)]):
# GGUF: move quantized data to CPU (preserves GGMLTensor attributes)
self._modules[str(prev)].to(self.offload_device)
else:
# Safetensor: set to meta (vbar restores automatically)
_free_to_meta(self._modules[str(prev)])
for m in self._modules[str(prev)].modules():
for attr in ('_v', '_prefetch', '_v_signature'):
if hasattr(m, attr):
try:
delattr(m, attr)
except Exception:
pass
except Exception:
pass
# LOAD current block if GGUF
if _has_ggml_params(self._modules[str(idx)]):
self._modules[str(idx)].to(self.compute_device)
# else: safetensor - vbar handles restoration
self._loaded_swap_idx = local_idx
def offload_swap_blocks(self):
for i in range(self.non_swap_count, self.total_count):
try:
if _has_ggml_params(self._modules[str(i)]):
self._modules[str(i)].to(self.offload_device)
else:
_free_to_meta(self._modules[str(i)])
for m in self._modules[str(i)].modules():
for attr in ('_v', '_prefetch', '_v_signature'):
if hasattr(m, attr):
try:
delattr(m, attr)
except Exception:
pass
except Exception:
pass
self._loaded_swap_idx = -1
def _apply(self, fn, recurse=True):
"""Apply fn to non-swap blocks only.
CRITICAL: Prevents model.to(device_to) from moving swap block
GGMLTensors to GPU, which would cause a VRAM spike (12GB).
Safetensor swap blocks are already meta (no-op), so this only
affects GGUF paths.
nn.ModuleList._apply(recurse=False) applies fn to all _modules
entries INCLUDING swap blocks. We skip that and handle only
non_swap_count blocks manually.
"""
for i in range(self.non_swap_count):
try:
child = self._modules.get(str(i))
if child is not None:
child._apply(fn, recurse)
except Exception:
pass
return self
def __getattr__(self, name):
try:
idx = int(name)
if 0 <= idx < self.total_count:
return self.__getitem__(idx)
except (ValueError, TypeError):
pass
raise AttributeError(f"'{type(self).__name__}' has no attribute '{name}'")
def __getitem__(self, idx):
# Support slicing: blocks[start:end]
if isinstance(idx, slice):
start, stop, step = idx.indices(self.total_count)
return [self[i] for i in range(start, stop, step)]
if idx >= self.non_swap_count:
self._load_swap(idx - self.non_swap_count)
return super().__getitem__(idx)
def __iter__(self):
for idx in range(self.total_count):
yield self.__getitem__(idx)
def install_block_swap(diffusion_model, compute_device, offload_device,
num_blocks=-1):
all_containers = []
for name in CONTAINER_NAMES:
c = getattr(diffusion_model, name, None)
if isinstance(c, (nn.ModuleList, list)) and len(c) > 0 and hasattr(c[0], "forward"):
all_containers.append((name, c))
if not all_containers:
return None, lambda: None, set()
first_swl = None
all_names = set()
for name, orig in all_containers:
total = len(orig)
n = num_blocks if num_blocks > 0 else total
n = max(1, min(n, total))
swl = SwappableModuleList(
orig, compute_device, offload_device,
non_swap_count=total - n,
)
swl.container_name = name
setattr(diffusion_model, name, swl)
all_names.add(name)
if first_swl is None:
first_swl = swl
logger.info("UniBlockSwap: '%s' = %d blocks, swapping %d",
name, total, n)
# For GGUF: offload swap blocks to CPU immediately.
# Safetensor blocks stay on GPU (original behavior).
for i in range(total - n, total):
blk = swl._modules[str(i)]
if _has_ggml_params(blk):
blk.to(offload_device)
orig_fwd = diffusion_model.forward
def wrapped(*args, **kwargs):
try:
return orig_fwd(*args, **kwargs)
finally:
if torch.cuda.is_available():
torch.cuda.synchronize(compute_device)
gc.collect()
torch.cuda.empty_cache()
diffusion_model.forward = wrapped
def cleanup():
diffusion_model.forward = orig_fwd
for name, orig in all_containers:
setattr(diffusion_model, name, orig)
all_swls = []
for name in CONTAINER_NAMES:
c = getattr(diffusion_model, name, None)
if hasattr(c, 'offload_swap_blocks'):
all_swls.append(c)
return first_swl, cleanup, all_names, all_swls
def find_te_containers(cond_stage_model):
results = []
seen_ids = set()
def _recurse(module, depth=0):
if depth > 20:
return
for name in CONTAINER_NAMES:
c = getattr(module, name, None)
if (isinstance(c, (nn.ModuleList, list)) and
len(c) > 0 and hasattr(c[0], "forward") and
id(c) not in seen_ids):
seen_ids.add(id(c))
results.append((name, c, module))
for child_name, child in module.named_children():
if isinstance(child, (nn.ModuleList, list)):
continue
_recurse(child, depth + 1)
_recurse(cond_stage_model)
return results
def install_te_block_swap(cond_stage_model, compute_device, offload_device,
num_blocks=-1):
containers = find_te_containers(cond_stage_model)
if not containers:
return [], lambda: None, set()
mgr_list = []
container_names = set()
parent_to_mgrs = {}
for name, orig, parent in containers:
total = len(orig)
n = num_blocks if num_blocks > 0 else total
n = max(1, min(n, total))
swl = SwappableModuleList(
orig, compute_device, offload_device,
non_swap_count=total - n,
)
swl.container_name = name
setattr(parent, name, swl)
mgr_list.append(swl)
container_names.add(name)
parent_id = id(parent)
if parent_id not in parent_to_mgrs:
parent_to_mgrs[parent_id] = (parent, parent.forward, [])
parent_to_mgrs[parent_id][2].append(swl)
logger.info("UniBlockSwapTE: '%s' (%s) = %d blocks, swapping %d",
name, type(parent).__name__, total, n)
for i in range(total - n, total):
blk = swl._modules[str(i)]
if _has_ggml_params(blk):
blk.to(offload_device)
else:
_free_to_meta(blk)
wrapped_parents = []
for parent_id, (parent, orig_fwd, parent_mgrs) in parent_to_mgrs.items():
def make_wrapped(_orig_fwd=orig_fwd, _mgrs=parent_mgrs, _cdevice=compute_device,
_root=cond_stage_model):
def wrapped(*args, **kwargs):
try:
return _orig_fwd(*args, **kwargs)
finally:
for m in _mgrs:
m.offload_swap_blocks()
backup_cleaner = getattr(_root, '_uniblockswap_backup_cleanup', None)
patcher = getattr(_root, '_patcher_ref', None)
if backup_cleaner is not None and patcher is not None:
backup_cleaner(patcher)
if torch.cuda.is_available():
torch.cuda.synchronize(_cdevice)
gc.collect()
torch.cuda.empty_cache()
return wrapped
parent.forward = make_wrapped()
wrapped_parents.append((parent, orig_fwd))
def cleanup():
for name, orig, parent in containers:
current = getattr(parent, name, None)
if hasattr(current, 'offload_swap_blocks'):
setattr(parent, name, orig)
for parent, orig_fwd in wrapped_parents:
parent.forward = orig_fwd
return mgr_list, cleanup, container_names