diff options
Diffstat (limited to 'include/grpc++/impl/codegen/completion_queue.h')
-rw-r--r-- | include/grpc++/impl/codegen/completion_queue.h | 28 |
1 files changed, 25 insertions, 3 deletions
diff --git a/include/grpc++/impl/codegen/completion_queue.h b/include/grpc++/impl/codegen/completion_queue.h index ef00163b7e..03cecdc21c 100644 --- a/include/grpc++/impl/codegen/completion_queue.h +++ b/include/grpc++/impl/codegen/completion_queue.h @@ -52,6 +52,7 @@ #include <grpc++/impl/codegen/grpc_library.h> #include <grpc++/impl/codegen/status.h> #include <grpc++/impl/codegen/time.h> +#include <grpc/impl/codegen/atm.h> struct grpc_completion_queue; @@ -93,14 +94,17 @@ class ServerContext; extern CoreCodegenInterface* g_core_codegen_interface; -/// A thin wrapper around \a grpc_completion_queue (see / \a -/// src/core/surface/completion_queue.h). +/// A thin wrapper around \ref grpc_completion_queue (see \ref +/// src/core/lib/surface/completion_queue.h). +/// See \ref doc/cpp/perf_notes.md for notes on best practices for high +/// performance servers. class CompletionQueue : private GrpcLibraryCodegen { public: /// Default constructor. Implicitly creates a \a grpc_completion_queue /// instance. CompletionQueue() { cq_ = g_core_codegen_interface->grpc_completion_queue_create(nullptr); + InitialAvalanching(); // reserve this for the future shutdown } /// Wrap \a take, taking ownership of the instance. @@ -151,7 +155,8 @@ class CompletionQueue : private GrpcLibraryCodegen { /// Request the shutdown of the queue. /// - /// \warning This method must be called at some point. Once invoked, \a Next + /// \warning This method must be called at some point if this completion queue + /// is accessed with Next or AsyncNext. Once invoked, \a Next /// will start to return false and \a AsyncNext will return \a /// NextStatus::SHUTDOWN. Only once either one of these methods does that /// (that is, once the queue has been \em drained) can an instance of this @@ -165,6 +170,21 @@ class CompletionQueue : private GrpcLibraryCodegen { /// owership is performed. grpc_completion_queue* cq() { return cq_; } + /// Manage state of avalanching operations : completion queue tags that + /// trigger other completion queue operations. The underlying core completion + /// queue should not really shutdown until all avalanching operations have + /// been finalized. Note that we maintain the requirement that an avalanche + /// registration must take place before CQ shutdown (which must be maintained + /// elsehwere) + void InitialAvalanching() { + gpr_atm_rel_store(&avalanches_in_flight_, static_cast<gpr_atm>(1)); + } + void RegisterAvalanching() { + gpr_atm_no_barrier_fetch_add(&avalanches_in_flight_, + static_cast<gpr_atm>(1)); + }; + void CompleteAvalanching(); + private: // Friend synchronous wrappers so that they can access Pluck(), which is // a semi-private API geared towards the synchronous implementation. @@ -229,6 +249,8 @@ class CompletionQueue : private GrpcLibraryCodegen { } grpc_completion_queue* cq_; // owned + + gpr_atm avalanches_in_flight_; }; /// A specific type of completion queue used by the processing of notifications |