server : free draft/MTP resources on sleep to fix VRAM leak (#23461)
The destroy() function in server_context_impl only cleaned up the main
model and context (via llama_init.reset()) but did not free the speculative
decoder (spec), draft context (ctx_dft), or draft model (model_dft).
For MTP (Multi-Token Prediction) models, ctx_dft holds GPU-allocated
resources (KV cache, compute buffers) that are not freed when entering
the sleeping state. On each sleep/resume cycle, new resources are
allocated without the old ones being freed, leading to a VRAM leak
that eventually crashes the server with out-of-memory errors.
Fix by explicitly resetting spec, ctx_dft, and model_dft in destroy()
before resetting llama_init, ensuring proper cleanup order to avoid
use-after-free.
overview / pkg / ggml / sources / llama.cpp / commit