Add caching for model loading

server/model_loader.go

@@ -0,0 +1,63 @@
+package server
+
+import (
+	"fmt"
+	"sync"
+
+	"github.com/ollama/ollama/llama"
+	"github.com/ollama/ollama/types/model"
+)
+
+type loadedModel struct {
+	model     *llama.Model
+	modelPath string
+}
+
+// modelCache stores loaded models keyed by their full path and params hash
+var modelCache sync.Map // map[string]*loadedModel
+
+func LoadModel(name string, params llama.ModelParams) (*loadedModel, error) {
+	modelName := model.ParseName(name)
+	if !modelName.IsValid() {
+		return nil, fmt.Errorf("invalid model name: %s", modelName)
+	}
+
+	modelPath, err := GetModel(modelName.String())
+	if err != nil {
+		return nil, fmt.Errorf("model not found: %s", modelName)
+	}
+
+	// Create cache key from model path and params hash
+	cacheKey := fmt.Sprintf("%s-%+v", modelPath.ModelPath, params)
+	if cached, ok := modelCache.Load(cacheKey); ok {
+		return cached.(*loadedModel), nil
+	}
+
+	// Evict existing model if any
+	evictExistingModel()
+
+	model, err := llama.LoadModelFromFile(modelPath.ModelPath, params)
+	if err != nil {
+		return nil, fmt.Errorf("failed to load model: %v", err)
+	}
+
+	loaded := &loadedModel{
+		model:     model,
+		modelPath: modelPath.ModelPath,
+	}
+	modelCache.Store(cacheKey, loaded)
+
+	return loaded, nil
+}
+
+// evictExistingModel removes any currently loaded model from the cache
+// Currently only supports a single model in cache at a time
+// TODO: Add proper cache eviction policy (LRU/size/TTL based)
+func evictExistingModel() {
+	modelCache.Range(func(key, value any) bool {
+		if cached, ok := modelCache.LoadAndDelete(key); ok {
+			llama.FreeModel(cached.(*loadedModel).model)
+		}
+		return true
+	})
+}