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+/**
+ * Copyright (C) 2022-present MongoDB, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the Server Side Public License, version 1,
+ * as published by MongoDB, Inc.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * Server Side Public License for more details.
+ *
+ * You should have received a copy of the Server Side Public License
+ * along with this program. If not, see
+ * <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ * As a special exception, the copyright holders give permission to link the
+ * code of portions of this program with the OpenSSL library under certain
+ * conditions as described in each individual source file and distribute
+ * linked combinations including the program with the OpenSSL library. You
+ * must comply with the Server Side Public License in all respects for
+ * all of the code used other than as permitted herein. If you modify file(s)
+ * with this exception, you may extend this exception to your version of the
+ * file(s), but you are not obligated to do so. If you do not wish to do so,
+ * delete this exception statement from your version. If you delete this
+ * exception statement from all source files in the program, then also delete
+ * it in the license file.
+ */
+#pragma once
+
+#if defined(__linux__)
+#include <semaphore.h>
+#endif
+
+#include <queue>
+
+#include "mongo/db/operation_context.h"
+#include "mongo/db/service_context.h"
+#include "mongo/platform/mutex.h"
+#include "mongo/stdx/condition_variable.h"
+#include "mongo/util/concurrency/admission_context.h"
+#include "mongo/util/concurrency/mutex.h"
+#include "mongo/util/concurrency/ticket_queues.h"
+#include "mongo/util/concurrency/ticketholder.h"
+#include "mongo/util/hierarchical_acquisition.h"
+#include "mongo/util/time_support.h"
+
+namespace mongo {
+
+class SemaphoreTicketHolder final : public TicketHolderWithQueueingStats {
+public:
+ explicit SemaphoreTicketHolder(int numTickets, ServiceContext* serviceContext);
+ ~SemaphoreTicketHolder() override final;
+
+ int available() const override final;
+
+ int queued() const override final {
+ auto removed = _semaphoreStats.totalRemovedQueue.loadRelaxed();
+ auto added = _semaphoreStats.totalAddedQueue.loadRelaxed();
+ return std::max(static_cast<int>(added - removed), 0);
+ };
+
+ bool recordImmediateTicketStatistics() noexcept override final {
+ // Historically, operations that now acquire 'immediate' tickets bypassed the ticketing
+ // mechanism completely. Preserve legacy behavior where 'immediate' ticketing is not tracked
+ // in the statistics.
+ return false;
+ }
+
+private:
+ boost::optional<Ticket> _waitForTicketUntilImpl(OperationContext* opCtx,
+ AdmissionContext* admCtx,
+ Date_t until,
+ WaitMode waitMode) override final;
+
+ boost::optional<Ticket> _tryAcquireImpl(AdmissionContext* admCtx) override final;
+ void _releaseToTicketPoolImpl(AdmissionContext* admCtx) noexcept override final;
+
+ void _appendImplStats(BSONObjBuilder& b) const override final;
+
+ void _resize(int newSize, int oldSize) noexcept override final;
+
+ QueueStats& _getQueueStatsToUse(const AdmissionContext* admCtx) noexcept override final {
+ return _semaphoreStats;
+ }
+#if defined(__linux__)
+ mutable sem_t _sem;
+
+#else
+ bool _tryAcquire();
+
+ int _numTickets;
+ Mutex _mutex =
+ MONGO_MAKE_LATCH(HierarchicalAcquisitionLevel(0), "SemaphoreTicketHolder::_mutex");
+ stdx::condition_variable _newTicket;
+#endif
+ QueueStats _semaphoreStats;
+};
+
+} // namespace mongo