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sd: fix VAE tiled fallback VRAM leak #10139

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Merged
merged 1 commit into from
Oct 1, 2025
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sd: fix VAE tiled fallback VRAM leak #10139

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16 changes: 16 additions & 0 deletions comfy/sd.py
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Original file line number Diff line number Diff line change
Expand Up @@ -636,6 +636,7 @@ def encode_tiled_3d(self, samples, tile_t=9999, tile_x=512, tile_y=512, overlap=
def decode(self, samples_in, vae_options={}):
self.throw_exception_if_invalid()
pixel_samples = None
do_tile = False
try:
memory_used = self.memory_used_decode(samples_in.shape, self.vae_dtype)
model_management.load_models_gpu([self.patcher], memory_required=memory_used, force_full_load=self.disable_offload)
Expand All @@ -651,6 +652,13 @@ def decode(self, samples_in, vae_options={}):
pixel_samples[x:x+batch_number] = out
except model_management.OOM_EXCEPTION:
logging.warning("Warning: Ran out of memory when regular VAE decoding, retrying with tiled VAE decoding.")
#NOTE: We don't know what tensors were allocated to stack variables at the time of the
#exception and the exception itself refs them all until we get out of this except block.
#So we just set a flag for tiler fallback so that tensor gc can happen once the
#exception is fully off the books.
do_tile = True

if do_tile:
dims = samples_in.ndim - 2
if dims == 1 or self.extra_1d_channel is not None:
pixel_samples = self.decode_tiled_1d(samples_in)
Expand Down Expand Up @@ -697,6 +705,7 @@ def encode(self, pixel_samples):
self.throw_exception_if_invalid()
pixel_samples = self.vae_encode_crop_pixels(pixel_samples)
pixel_samples = pixel_samples.movedim(-1, 1)
do_tile = False
if self.latent_dim == 3 and pixel_samples.ndim < 5:
if not self.not_video:
pixel_samples = pixel_samples.movedim(1, 0).unsqueeze(0)
Expand All @@ -718,6 +727,13 @@ def encode(self, pixel_samples):

except model_management.OOM_EXCEPTION:
logging.warning("Warning: Ran out of memory when regular VAE encoding, retrying with tiled VAE encoding.")
#NOTE: We don't know what tensors were allocated to stack variables at the time of the
#exception and the exception itself refs them all until we get out of this except block.
#So we just set a flag for tiler fallback so that tensor gc can happen once the
#exception is fully off the books.
do_tile = True

if do_tile:
if self.latent_dim == 3:
tile = 256
overlap = tile // 4
Expand Down