1 files changed, 4 insertions, 196 deletions

diff --git a/src/mongo/util/concurrency/ticketholder.h b/src/mongo/util/concurrency/ticketholder.h
index a87dacca15f..5d16ef1ae25 100644
--- a/src/mongo/util/concurrency/ticketholder.h
+++ b/src/mongo/util/concurrency/ticketholder.h
@@ -28,12 +28,6 @@
  */
 #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"
@@ -41,13 +35,14 @@
 #include "mongo/stdx/future.h"
 #include "mongo/util/concurrency/admission_context.h"
 #include "mongo/util/concurrency/mutex.h"
-#include "mongo/util/concurrency/ticket_queues.h"
 #include "mongo/util/hierarchical_acquisition.h"
 #include "mongo/util/time_support.h"
 
 namespace mongo {
 
 class Ticket;
+class PriorityTicketHolder;
+class SemaphoreTicketHolder;
 
 /**
  * Maintains and distributes tickets across operations from a limited pool of tickets. The ticketing
@@ -224,198 +219,11 @@ private:
     AtomicWord<int> _outof;
 
 protected:
-    ServiceContext* _serviceContext;
-};
-
-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;
-};
-
-/**
- * A ticketholder implementation that centralises all ticket acquisition/releases.  Waiters will get
- * placed in a specific internal queue according to some logic.  Releasers will wake up a waiter
- * from a group chosen according to some logic.
- */
-class PriorityTicketHolder : public TicketHolderWithQueueingStats {
-public:
-    explicit PriorityTicketHolder(int numTickets,
-                                  int lowPriorityBypassThreshold,
-                                  ServiceContext* serviceContext);
-    ~PriorityTicketHolder() override{};
-
-    int available() const override final {
-        return _ticketsAvailable.load();
-    };
-
-    int queued() const override final {
-        return _enqueuedElements.loadRelaxed();
-    }
-
-    bool recordImmediateTicketStatistics() noexcept override final {
-        return true;
-    };
-
     /**
-     * Number of times low priority operations are expedited for ticket admission over normal
-     * priority operations.
+     * Appends the standard statistics stored in QueueStats to BSONObjBuilder b;
      */
-    std::int64_t expedited() const {
-        return _expeditedLowPriorityAdmissions.loadRelaxed();
-    }
+    void _appendCommonQueueImplStats(BSONObjBuilder& b, const QueueStats& stats) const;
 
-    /**
-     * Returns the number of times the low priority queue is bypassed in favor of dequeuing from the
-     * normal priority queue when a ticket becomes available.
-     */
-    std::int64_t bypassed() const {
-        return _lowPriorityBypassCount.loadRelaxed();
-    };
-
-    void updateLowPriorityAdmissionBypassThreshold(const int& newBypassThreshold);
-
-private:
-    enum class QueueType : unsigned int {
-        kLowPriority = 0,
-        kNormalPriority = 1,
-        // Exclusively used for statistics tracking. This queue should never have any processes
-        // 'queued'.
-        kImmediatePriority = 2,
-        QueueTypeSize = 3
-    };
-
-    boost::optional<Ticket> _tryAcquireImpl(AdmissionContext* admCtx) override final;
-
-    boost::optional<Ticket> _waitForTicketUntilImpl(OperationContext* opCtx,
-                                                    AdmissionContext* admCtx,
-                                                    Date_t until,
-                                                    WaitMode waitMode) override final;
-
-    void _releaseToTicketPoolImpl(AdmissionContext* admCtx) noexcept override final;
-
-    void _resize(int newSize, int oldSize) noexcept override final;
-
-    QueueStats& _getQueueStatsToUse(const AdmissionContext* admCtx) noexcept override final;
-
-    void _appendImplStats(BSONObjBuilder& b) const override final;
-
-    bool _tryAcquireTicket();
-
-    /**
-     * Wakes up a waiting thread (if it exists) in order for it to attempt to obtain a ticket.
-     * Implementors MUST wake at least one waiting thread if at least one thread is pending to be
-     * woken between all the queues. In other words, attemptToDequeue on each non-empty Queue must
-     * be called until either it returns true at least once or has been called on all queues.
-     *
-     * Care must be taken to ensure that only CPU-bound work is performed here and it doesn't block.
-     *
-     * When called the following invariants will be held:
-     * - The number of items in each queue will not change during the execution
-     * - No other thread will proceed to wait during the execution of the method
-     */
-    void _dequeueWaitingThread(const ticket_queues::SharedLockGuard& sharedQueueLock);
-
-    /**
-     * Returns whether there are higher priority threads pending to get a ticket in front of the
-     * given queue type and not enough tickets for all of them.
-     */
-    bool _hasToWaitForHigherPriority(const ticket_queues::UniqueLockGuard& lk, QueueType queueType);
-
-    unsigned int _enumToInt(QueueType queueType) {
-        return static_cast<unsigned int>(queueType);
-    }
-    unsigned int _enumToInt(QueueType queueType) const {
-        return static_cast<unsigned int>(queueType);
-    }
-
-    ticket_queues::Queue& _getQueue(QueueType queueType) {
-        return _queues[_enumToInt(queueType)];
-    }
-
-
-    QueueType _getQueueType(const AdmissionContext* admCtx) {
-        auto priority = admCtx->getPriority();
-        switch (priority) {
-            case AdmissionContext::Priority::kLow:
-                return QueueType::kLowPriority;
-            case AdmissionContext::Priority::kNormal:
-                return QueueType::kNormalPriority;
-            case AdmissionContext::Priority::kImmediate:
-                return QueueType::kImmediatePriority;
-            default:
-                MONGO_UNREACHABLE;
-        }
-    }
-
-    ticket_queues::QueueMutex _queueMutex;
-    std::array<ticket_queues::Queue, static_cast<unsigned int>(QueueType::QueueTypeSize)> _queues;
-    std::array<QueueStats, static_cast<unsigned int>(QueueType::QueueTypeSize)> _stats;
-
-    /**
-     * Limits the number times the low priority queue is non-empty and bypassed in favor of the
-     * normal priority queue for the next ticket admission.
-     *
-     * Updates must be done under the ticket_queues::UniqueLockGuard.
-     */
-    int _lowPriorityBypassThreshold;
-
-    /**
-     * Counts the number of times normal operations are dequeued over operations queued in the low
-     * priority queue.
-     */
-    AtomicWord<std::uint64_t> _lowPriorityBypassCount{0};
-
-    /**
-     * Number of times ticket admission is expedited for low priority operations.
-     */
-    AtomicWord<std::int64_t> _expeditedLowPriorityAdmissions{0};
-    AtomicWord<int> _ticketsAvailable;
-    AtomicWord<int> _enqueuedElements;
     ServiceContext* _serviceContext;
 };