ceph/src/rocksdb/monitoring/thread_status_util.h

   1 // Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
   2 // This source code is licensed under the BSD-style license found in the
   3 // LICENSE file in the root directory of this source tree. An additional grant
   4 // of patent rights can be found in the PATENTS file in the same directory.
   5
   6 #pragma once
   7
   8 #include <string>
   9
  10 #include "monitoring/thread_status_updater.h"
  11 #include "rocksdb/db.h"
  12 #include "rocksdb/env.h"
  13 #include "rocksdb/thread_status.h"
  14
  15 namespace rocksdb {
  16
  17 class ColumnFamilyData;
  18
  19 // The static utility class for updating thread-local status.
  20 //
  21 // The thread-local status is updated via the thread-local cached
  22 // pointer thread_updater_local_cache_.  During each function call,
  23 // when ThreadStatusUtil finds thread_updater_local_cache_ is
  24 // left uninitialized (determined by thread_updater_initialized_),
  25 // it will tries to initialize it using the return value of
  26 // Env::GetThreadStatusUpdater().  When thread_updater_local_cache_
  27 // is initialized by a non-null pointer, each function call will
  28 // then update the status of the current thread.  Otherwise,
  29 // all function calls to ThreadStatusUtil will be no-op.
  30 class ThreadStatusUtil {
  31  public:
  32   // Register the current thread for tracking.
  33   static void RegisterThread(
  34       const Env* env, ThreadStatus::ThreadType thread_type);
  35
  36   // Unregister the current thread.
  37   static void UnregisterThread();
  38
  39   // Create an entry in the global ColumnFamilyInfo table for the
  40   // specified column family.  This function should be called only
  41   // when the current thread does not hold db_mutex.
  42   static void NewColumnFamilyInfo(const DB* db, const ColumnFamilyData* cfd,
  43                                   const std::string& cf_name, const Env* env);
  44
  45   // Erase the ConstantColumnFamilyInfo that is associated with the
  46   // specified ColumnFamilyData.  This function should be called only
  47   // when the current thread does not hold db_mutex.
  48   static void EraseColumnFamilyInfo(const ColumnFamilyData* cfd);
  49
  50   // Erase all ConstantColumnFamilyInfo that is associated with the
  51   // specified db instance.  This function should be called only when
  52   // the current thread does not hold db_mutex.
  53   static void EraseDatabaseInfo(const DB* db);
  54
  55   // Update the thread status to indicate the current thread is doing
  56   // something related to the specified column family.
  57   static void SetColumnFamily(const ColumnFamilyData* cfd, const Env* env,
  58                               bool enable_thread_tracking);
  59
  60   static void SetThreadOperation(ThreadStatus::OperationType type);
  61
  62   static ThreadStatus::OperationStage SetThreadOperationStage(
  63       ThreadStatus::OperationStage stage);
  64
  65   static void SetThreadOperationProperty(
  66       int code, uint64_t value);
  67
  68   static void IncreaseThreadOperationProperty(
  69       int code, uint64_t delta);
  70
  71   static void SetThreadState(ThreadStatus::StateType type);
  72
  73   static void ResetThreadStatus();
  74
  75 #ifndef NDEBUG
  76   static void TEST_SetStateDelay(
  77       const ThreadStatus::StateType state, int micro);
  78   static void TEST_StateDelay(const ThreadStatus::StateType state);
  79 #endif
  80
  81  protected:
  82   // Initialize the thread-local ThreadStatusUpdater when it finds
  83   // the cached value is nullptr.  Returns true if it has cached
  84   // a non-null pointer.
  85   static bool MaybeInitThreadLocalUpdater(const Env* env);
  86
  87 #ifdef ROCKSDB_USING_THREAD_STATUS
  88   // A boolean flag indicating whether thread_updater_local_cache_
  89   // is initialized.  It is set to true when an Env uses any
  90   // ThreadStatusUtil functions using the current thread other
  91   // than UnregisterThread().  It will be set to false when
  92   // UnregisterThread() is called.
  93   //
  94   // When this variable is set to true, thread_updater_local_cache_
  95   // will not be updated until this variable is again set to false
  96   // in UnregisterThread().
  97   static  __thread bool thread_updater_initialized_;
  98
  99   // The thread-local cached ThreadStatusUpdater that caches the
 100   // thread_status_updater_ of the first Env that uses any ThreadStatusUtil
 101   // function other than UnregisterThread().  This variable will
 102   // be cleared when UnregisterThread() is called.
 103   //
 104   // When this variable is set to a non-null pointer, then the status
 105   // of the current thread will be updated when a function of
 106   // ThreadStatusUtil is called.  Otherwise, all functions of
 107   // ThreadStatusUtil will be no-op.
 108   //
 109   // When thread_updater_initialized_ is set to true, this variable
 110   // will not be updated until this thread_updater_initialized_ is
 111   // again set to false in UnregisterThread().
 112   static __thread ThreadStatusUpdater* thread_updater_local_cache_;
 113 #else
 114   static bool thread_updater_initialized_;
 115   static ThreadStatusUpdater* thread_updater_local_cache_;
 116 #endif
 117 };
 118
 119 // A helper class for updating thread state.  It will set the
 120 // thread state according to the input parameter in its constructor
 121 // and set the thread state to the previous state in its destructor.
 122 class AutoThreadOperationStageUpdater {
 123  public:
 124   explicit AutoThreadOperationStageUpdater(
 125       ThreadStatus::OperationStage stage);
 126   ~AutoThreadOperationStageUpdater();
 127
 128 #ifdef ROCKSDB_USING_THREAD_STATUS
 129  private:
 130   ThreadStatus::OperationStage prev_stage_;
 131 #endif
 132 };
 133
 134 }  // namespace rocksdb