fix(scanner): respect lazy hash for checkpoints, add posix_fadvise, cancel on shutdown (#985)

py/lora_manager.py

@@ -436,5 +436,14 @@ class LoraManager:
         try:
             logger.info("LoRA Manager: Cleaning up services")
 
+            # Cancel any in-flight scanner initialization tasks so thread-pool
+            # workers (e.g. _initialize_cache_sync) can break out of their loops
+            # when the server shuts down (e.g. Ctrl+C on WSL).
+            for name in ("lora_scanner", "checkpoint_scanner", "embedding_scanner"):
+                scanner = ServiceRegistry.get_service_sync(name)
+                if scanner is not None and hasattr(scanner, "cancel_task"):
+                    scanner.cancel_task()
+                    logger.debug("LoRA Manager: Cancelled %s", name)
+
         except Exception as e:
             logger.error(f"Error during cleanup: {e}", exc_info=True)

py/services/model_scanner.py

@@ -1067,8 +1067,11 @@ class ModelScanner:
 
         model_data = self._build_cache_entry(metadata, folder=normalized_folder)
 
-        # Compute SHA256 hash when metadata provided none (e.g., CivitAI API response has empty hashes)
-        if not model_data.get('sha256') and file_path:
+        # Compute SHA256 hash when metadata provided none (e.g., CivitAI API response has empty hashes).
+        # Respect hash_status='pending' (set by CheckpointScanner for large models) to defer
+        # hash calculation until on-demand — avoids reading entire checkpoint files at startup.
+        hash_status = model_data.get('hash_status', '')
+        if not model_data.get('sha256') and hash_status != 'pending' and file_path:
             try:
                 logger.info(f"Computing SHA256 hash for {file_path} (was empty from metadata)")
                 sha256 = await calculate_sha256(file_path)

py/utils/file_utils.py

@@ -34,10 +34,17 @@ def _get_hash_chunk_size_bytes() -> int:
 
 
 async def calculate_sha256(file_path: str) -> str:
-    """Calculate SHA256 hash of a file (full file content)."""
+    """Calculate SHA256 hash of a file (full file content).
+
+    Uses ``posix_fadvise`` with ``POSIX_FADV_DONTNEED`` to avoid polluting the OS page
+    cache — critical on WSL where cached file pages live inside the VM and are not
+    accounted for in guest ``used`` memory, causing VmmemWSL to balloon.
+    """
     sha256_hash = hashlib.sha256()
     chunk_size = _get_hash_chunk_size_bytes()
     with open(file_path, "rb") as f:
+        fd = f.fileno()
+        os.posix_fadvise(fd, 0, 0, os.POSIX_FADV_DONTNEED)
         for byte_block in iter(lambda: f.read(chunk_size), b""):
             sha256_hash.update(byte_block)
     return sha256_hash.hexdigest()