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rust-rocksdb/monitoring/thread_status_util.h

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#pragma once
#include <string>
#include "monitoring/thread_status_updater.h"
#include "rocksdb/db.h"
#include "rocksdb/env.h"
#include "rocksdb/thread_status.h"
namespace ROCKSDB_NAMESPACE {
class ColumnFamilyData;
// The static utility class for updating thread-local status.
//
// The thread-local status is updated via the thread-local cached
// pointer thread_updater_local_cache_. During each function call,
// when ThreadStatusUtil finds thread_updater_local_cache_ is
// left uninitialized (determined by thread_updater_initialized_),
// it will tries to initialize it using the return value of
// Env::GetThreadStatusUpdater(). When thread_updater_local_cache_
// is initialized by a non-null pointer, each function call will
// then update the status of the current thread. Otherwise,
// all function calls to ThreadStatusUtil will be no-op.
class ThreadStatusUtil {
public:
// Register the current thread for tracking.
static void RegisterThread(const Env* env,
ThreadStatus::ThreadType thread_type);
// Unregister the current thread.
static void UnregisterThread();
// Create an entry in the global ColumnFamilyInfo table for the
// specified column family. This function should be called only
// when the current thread does not hold db_mutex.
static void NewColumnFamilyInfo(const DB* db, const ColumnFamilyData* cfd,
const std::string& cf_name, const Env* env);
// Erase the ConstantColumnFamilyInfo that is associated with the
// specified ColumnFamilyData. This function should be called only
// when the current thread does not hold db_mutex.
static void EraseColumnFamilyInfo(const ColumnFamilyData* cfd);
// Erase all ConstantColumnFamilyInfo that is associated with the
// specified db instance. This function should be called only when
// the current thread does not hold db_mutex.
static void EraseDatabaseInfo(const DB* db);
static void SetEnableTracking(bool enable_tracking);
// Update the thread status to indicate the current thread is doing
// something related to the specified column family.
//
// REQUIRES: cfd != nullptr
static void SetColumnFamily(const ColumnFamilyData* cfd);
static void SetThreadOperation(ThreadStatus::OperationType type);
static ThreadStatus::OperationType GetThreadOperation();
static ThreadStatus::OperationStage SetThreadOperationStage(
ThreadStatus::OperationStage stage);
static void SetThreadOperationProperty(int code, uint64_t value);
static void IncreaseThreadOperationProperty(int code, uint64_t delta);
static void SetThreadState(ThreadStatus::StateType type);
static void ResetThreadStatus();
#ifndef NDEBUG
static void TEST_SetStateDelay(const ThreadStatus::StateType state,
int micro);
static void TEST_StateDelay(const ThreadStatus::StateType state);
static Env::IOActivity TEST_GetExpectedIOActivity(
ThreadStatus::OperationType thread_op);
#endif
protected:
// Initialize the thread-local ThreadStatusUpdater when it finds
// the cached value is nullptr. Returns true if it has cached
// a non-null pointer.
static bool MaybeInitThreadLocalUpdater(const Env* env);
#ifdef ROCKSDB_USING_THREAD_STATUS
// A boolean flag indicating whether thread_updater_local_cache_
// is initialized. It is set to true when an Env uses any
// ThreadStatusUtil functions using the current thread other
// than UnregisterThread(). It will be set to false when
// UnregisterThread() is called.
//
// When this variable is set to true, thread_updater_local_cache_
// will not be updated until this variable is again set to false
// in UnregisterThread().
static thread_local bool thread_updater_initialized_;
// The thread-local cached ThreadStatusUpdater that caches the
// thread_status_updater_ of the first Env that uses any ThreadStatusUtil
// function other than UnregisterThread(). This variable will
// be cleared when UnregisterThread() is called.
//
// When this variable is set to a non-null pointer, then the status
// of the current thread will be updated when a function of
// ThreadStatusUtil is called. Otherwise, all functions of
// ThreadStatusUtil will be no-op.
//
// When thread_updater_initialized_ is set to true, this variable
// will not be updated until this thread_updater_initialized_ is
// again set to false in UnregisterThread().
static thread_local ThreadStatusUpdater* thread_updater_local_cache_;
#else
static bool thread_updater_initialized_;
static ThreadStatusUpdater* thread_updater_local_cache_;
#endif
};
// A helper class for updating thread state. It will set the
// thread state according to the input parameter in its constructor
// and set the thread state to the previous state in its destructor.
class AutoThreadOperationStageUpdater {
public:
explicit AutoThreadOperationStageUpdater(ThreadStatus::OperationStage stage);
~AutoThreadOperationStageUpdater();
#ifdef ROCKSDB_USING_THREAD_STATUS
private:
ThreadStatus::OperationStage prev_stage_;
#endif
};
} // namespace ROCKSDB_NAMESPACE