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Diffstat (limited to 'src/mongo/db/repl/delayable_timeout_callback.h')
| -rw-r--r-- | src/mongo/db/repl/delayable_timeout_callback.h | 159 |
1 files changed, 0 insertions, 159 deletions
diff --git a/src/mongo/db/repl/delayable_timeout_callback.h b/src/mongo/db/repl/delayable_timeout_callback.h deleted file mode 100644 index d1cb8e29f95..00000000000 --- a/src/mongo/db/repl/delayable_timeout_callback.h +++ /dev/null @@ -1,159 +0,0 @@ -/** - * 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 - -#include <string> - -#include "mongo/base/status.h" -#include "mongo/executor/task_executor.h" -#include "mongo/util/time_support.h" - -namespace mongo { -namespace repl { - -/** - * The DelayableTimeoutCallback is a utility class which allows a callback to be scheduled on an - * executor at a given time, and then that time pushed back (later) arbitrarily often without - * rescheduling the call on the executor. The callback is never called with CallbackCanceled or - * ShutdownInProgress. - * - * All methods are thread safe, though isActive() and getNextCall() may return stale information - * if external synchronization is not used. The callback is called without any locks held. - */ -class DelayableTimeoutCallback { -public: - /** - * Creates a DelayableTimeoutCallback with the given executor and callback function. The - * DelayableTimeoutCallback is inactive (the callback is not scheduled) when constructed. - */ - DelayableTimeoutCallback(executor::TaskExecutor* executor, - executor::TaskExecutor::CallbackFn callback, - std::string timerName = std::string()) - : _executor(executor), _callback(std::move(callback)), _timerName(std::move(timerName)){}; - - ~DelayableTimeoutCallback(); - - /** - * If the timeout is scheduled, cancel it. The callback function will not be called. - */ - void cancel(); - - /** - * Schedule the timeout to occur at "when", regardless of if or when it is already scheduled. - * If it is already scheduled to occur after "when", it is canceled and rescheduled - * - * Returns status of the attempt to schedule on the executor. - */ - Status scheduleAt(Date_t when); - - /** - * Schedule the timeout to occur at "when" if it is not scheduled or scheduled to occur before - * "when". If it is already scheduled to occur before "when", this call has no effect. - * - * Returns status of the attempt to schedule on the executor. - */ - Status delayUntil(Date_t when); - - /** - * Returns whether the callback is scheduled at all. - */ - bool isActive() const; - - /** - * Returns when the next call to the passed-in callback will be made, or Date_t() if inactive. - */ - Date_t getNextCall() const; - -protected: - void _cancel(WithLock); - Status _scheduleAt(WithLock, Date_t when); - Status _delayUntil(WithLock, Date_t when); - executor::TaskExecutor* _getExecutor() { - return _executor; - } - - mutable Mutex _mutex = MONGO_MAKE_LATCH("DelayableTimeoutCallback"); - -private: - void _handleTimeout(const executor::TaskExecutor::CallbackArgs& cbData); - Status _reschedule(WithLock, Date_t when); - - executor::TaskExecutor* _executor; - executor::TaskExecutor::CallbackHandle _cbHandle; - const executor::TaskExecutor::CallbackFn _callback; - Date_t _nextCall; - - // Timer name is used only for logging. - const std::string _timerName; -}; - -/** - * DelayableTimeoutCallbackWithJitter is a slight variation on DelayableTimeoutCallback - * which adds some additional random time to delays. Since the callback may be delayed at - * intervals much shorter than the random time, this would naively result in the timeout - * either being moved backwards often, or if we forbid moving it backwards, ending up quickly - * moving to the maximum jitter (which isn't very random). To avoid that, we only recompute - * the jitter every maximum jitter interval -- e.g. if the max jitter is 10 seconds and we - * add 3 seconds jitter at time T, we will add 3 seconds jitter to every subsequent call until - * time T + 10. - * - * The typical purpose of the jitter is to prevent two timers receiving delay calls at the same - * times from firing at the same time. - * - * Synchronization of the randomSource is up to the caller; it is provided externally to - * avoid having a separate random number generator per timer. The randomSource function will - * be called with the maximum jitter value passed to delayUntilWithJitter; it should return - * a value in the range [0, maxJitter) or [0, maxJitter] depending on what you want the - * actual jitter range to be. - */ -class DelayableTimeoutCallbackWithJitter : public DelayableTimeoutCallback { -public: - using RandomSource = std::function<int64_t(int64_t)>; - - DelayableTimeoutCallbackWithJitter(executor::TaskExecutor* executor, - executor::TaskExecutor::CallbackFn callback, - RandomSource randomSource, - std::string timerName = std::string()) - : DelayableTimeoutCallback(executor, std::move(callback), timerName), - _randomSource(std::move(randomSource)) {} - - Status scheduleAt(Date_t when); - Status delayUntil(Date_t when); - Status delayUntilWithJitter(Date_t when, Milliseconds maxJitter); - -private: - void _resetRandomization(WithLock); - - RandomSource _randomSource; - Date_t _lastRandomizationTime; - Milliseconds _currentJitter; -}; - -} // namespace repl -} // namespace mongo |