[Model Runner V2] Fix warmup for very small kvcache and/or blocksizes (#36176)

Signed-off-by: Nick Hill <nickhill123@gmail.com>

vllm/v1/worker/gpu_worker.py

@@ -464,6 +464,10 @@ class Worker(WorkerBase):
     def initialize_from_config(self, kv_cache_config: KVCacheConfig) -> None:
         """Allocate GPU KV cache with the specified kv_cache_config."""
 
+        # Update local config with adjusted num blocks after profiling,
+        # so that it's available to the warmup stage.
+        self.cache_config.num_gpu_blocks = kv_cache_config.num_blocks
+
         # Init kv cache connector here, because it requires
         # `kv_cache_config`.
         # NOTE(Kuntai): This need to be done before `initialize_kv_cache`,