- The image and video load guards read is_active() and only then selected an
engine, acquired the arbiter and registered the load. A /train/diffusion/start
reserving inside that window freed residents the load had not registered yet,
so the trainer came up beside a brand-new pipeline. The service already had
exactly the right pattern for this in dataset_mutation, so gpu_load_admission
mirrors it: reserve() refuses while an admission is open, an admission refuses
once a start is reserved, both decided under the one lock. The span is only the
registration, since begin_load returns as soon as the load is registered and
_free_gpu_for_diffusion_training preempts an in-flight load from that point.
Chat is deliberately not covered: its load spans an eviction plus a multi-minute
GGUF load, and it admits models that fit beside training by design, which is a
different contract from the diffusion pipeline's all-or-nothing one.
- Hugging Face gives the LTX-2 family the image-to-video pipeline_tag (both
Lightricks/LTX-2 and unsloth/LTX-2.3-GGUF report it), so a text-to-video-only
filter dropped the flagship audio family out of Video Hub search while the rest
of the app routed it to Video.
- Task-scoped quant fit sized picks against the LARGEST visible device while
resolve_diffusion_device_target returns a bare "cuda" and torch places on the
current one. On a heterogeneous host that recommended a checkpoint sized for the
bigger card and then loaded it onto the smaller one. Fit now uses the device the
load actually lands on; identical on a homogeneous host.
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