[OVEP] Enable Session Option to Stop Context Sharing (#822)

This PR enables the session option: StopShareEpContexts ("ep.stop_share_ep_contexts" = 1/0), to explicitly clear the globally shared EP context after a session completes. This allows controlled cleanup of shared weights, metadata, its file path, and other cached artifacts stored in SharedContext.

For example, for model abc and model xyz:

model_abc(ep.share_ep_contexts=1, ep.stop_share_ep_contexts=1)
After this session, all existing shared context data is cleared.

model_xyz(ep.share_ep_contexts=1)
This model starts with a fresh shared context, without any leftover metadata or weights from model_abc.

Fixed format and unique pointer handling.

Author: n1harika

onnxruntime/core/providers/openvino/contexts.h

@@ -61,11 +61,22 @@ class SharedContext : public WeakSingleton<SharedContext> {
       size_t weights_size_;
     };
 
+    void clear() {
+      metadata.clear();
+      metadata_filepath.clear();
+      external_weight_filename.clear();
+      mapped_weights.reset();
+    }
+
     fs::path external_weight_filename;
     std::unique_ptr<WeightsFile> mapped_weights;
     Metadata::Map metadata;
     fs::path metadata_filepath;
   } shared_weights;
+
+  void clear() {
+    shared_weights.clear();
+  }
 };
 
 using config_t = std::map<std::string, ov::AnyMap>;
@@ -109,6 +120,7 @@ struct ProviderInfo {
   bool so_context_embed_mode{false};       // ORT session option
   bool so_share_ep_contexts{false};        // ORT session option
   fs::path so_context_file_path{};         // ORT session option
+  bool so_stop_share_ep_contexts{false};   // ORT session option
   const ConfigOptions* config_options{NULL};
   const std::unordered_set<std::string> valid_provider_keys = {"device_type", "device_id", "device_luid", "cache_dir", "precision",
                                                                "load_config", "context", "num_of_threads", "model_priority", "num_streams", "enable_opencl_throttling", "enable_qdq_optimizer",

onnxruntime/core/providers/openvino/openvino_execution_provider.cc

@@ -65,6 +65,7 @@ OpenVINOExecutionProvider::~OpenVINOExecutionProvider() {
     backend_manager.ShutdownBackendManager();
   }
   backend_managers_.clear();
+  shared_context_.reset();
 }
 
 std::vector<std::unique_ptr<ComputeCapability>>
@@ -214,6 +215,12 @@ common::Status OpenVINOExecutionProvider::Compile(
     file << metadata;
   }
 
+  if (session_context_.so_stop_share_ep_contexts) {
+    if (shared_context_) {
+      shared_context_->clear();
+    }
+  }
+
   return status;
 }
 

onnxruntime/core/providers/openvino/openvino_provider_factory.cc

@@ -28,6 +28,7 @@ void ParseConfigOptions(ProviderInfo& pi) {
   pi.so_context_embed_mode = pi.config_options->GetConfigOrDefault(kOrtSessionOptionEpContextEmbedMode, "0") == "1";
   pi.so_share_ep_contexts = pi.config_options->GetConfigOrDefault(kOrtSessionOptionShareEpContexts, "0") == "1";
   pi.so_context_file_path = pi.config_options->GetConfigOrDefault(kOrtSessionOptionEpContextFilePath, "");
+  pi.so_stop_share_ep_contexts = pi.config_options->GetConfigOrDefault(kOrtSessionOptionStopShareEpContexts, "0") == "1";
 
   if (pi.so_share_ep_contexts) {
     ov::AnyMap map;