| // Copyright 2021 gRPC authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #ifndef GRPC_CORE_LIB_RESOURCE_QUOTA_THREAD_QUOTA_H |
| #define GRPC_CORE_LIB_RESOURCE_QUOTA_THREAD_QUOTA_H |
| |
| #include <grpc/support/port_platform.h> |
| |
| #include <cstddef> |
| #include <limits> |
| |
| #include "absl/base/thread_annotations.h" |
| |
| #include "src/core/lib/gprpp/ref_counted.h" |
| #include "src/core/lib/gprpp/ref_counted_ptr.h" |
| #include "src/core/lib/gprpp/sync.h" |
| |
| namespace grpc_core { |
| |
| // Tracks the amount of threads in a resource quota. |
| class ThreadQuota : public RefCounted<ThreadQuota> { |
| public: |
| ThreadQuota(); |
| ~ThreadQuota() override; |
| |
| ThreadQuota(const ThreadQuota&) = delete; |
| ThreadQuota& operator=(const ThreadQuota&) = delete; |
| |
| // Set the maximum number of threads that can be used by this quota. |
| // If there are more, new reservations will fail until the quota is available. |
| void SetMax(size_t new_max); |
| |
| // Try to allocate some number of threads. |
| // Returns true if the allocation succeeded, false otherwise. |
| bool Reserve(size_t num_threads); |
| |
| // Release some number of threads. |
| void Release(size_t num_threads); |
| |
| private: |
| Mutex mu_; |
| size_t allocated_ ABSL_GUARDED_BY(mu_) = 0; |
| size_t max_ ABSL_GUARDED_BY(mu_) = std::numeric_limits<size_t>::max(); |
| }; |
| |
| using ThreadQuotaPtr = RefCountedPtr<ThreadQuota>; |
| |
| } // namespace grpc_core |
| |
| #endif // GRPC_CORE_LIB_RESOURCE_QUOTA_THREAD_QUOTA_H |