src/sim/drain.cc

   1 /*
   2  * Copyright (c) 2012, 2015, 2017 ARM Limited
   3  * All rights reserved
   4  *
   5  * The license below extends only to copyright in the software and shall
   6  * not be construed as granting a license to any other intellectual
   7  * property including but not limited to intellectual property relating
   8  * to a hardware implementation of the functionality of the software
   9  * licensed hereunder.  You may use the software subject to the license
  10  * terms below provided that you ensure that this notice is replicated
  11  * unmodified and in its entirety in all distributions of the software,
  12  * modified or unmodified, in source code or in binary form.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions are
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  17  * notice, this list of conditions and the following disclaimer;
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  19  * notice, this list of conditions and the following disclaimer in the
  20  * documentation and/or other materials provided with the distribution;
  21  * neither the name of the copyright holders nor the names of its
  22  * contributors may be used to endorse or promote products derived from
  23  * this software without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  27  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 #include "sim/drain.hh"
  39
  40 #include <algorithm>
  41
  42 #include "base/logging.hh"
  43 #include "base/trace.hh"
  44 #include "debug/Drain.hh"
  45 #include "sim/sim_exit.hh"
  46 #include "sim/sim_object.hh"
  47
  48 DrainManager DrainManager::_instance;
  49
  50 DrainManager::DrainManager()
  51     : _count(0),
  52       _state(DrainState::Running)
  53 {
  54 }
  55
  56 DrainManager::~DrainManager()
  57 {
  58 }
  59
  60 bool
  61 DrainManager::tryDrain()
  62 {
  63     panic_if(_state == DrainState::Drained,
  64              "Trying to drain a drained system\n");
  65
  66     panic_if(_count != 0,
  67              "Drain counter must be zero at the start of a drain cycle\n");
  68
  69     DPRINTF(Drain, "Trying to drain %u objects.\n", drainableCount());
  70     _state = DrainState::Draining;
  71     for (auto *obj : _allDrainable) {
  72         DrainState status = obj->dmDrain();
  73         if (DTRACE(Drain) && status != DrainState::Drained) {
  74             SimObject *temp = dynamic_cast<SimObject*>(obj);
  75             if (temp)
  76                 DPRINTF(Drain, "Failed to drain %s\n", temp->name());
  77         }
  78         _count += status == DrainState::Drained ? 0 : 1;
  79     }
  80
  81     if (_count == 0) {
  82         DPRINTF(Drain, "Drain done.\n");
  83         _state = DrainState::Drained;
  84         return true;
  85     } else {
  86         DPRINTF(Drain, "Need another drain cycle. %u/%u objects not ready.\n",
  87                 _count, drainableCount());
  88         return false;
  89     }
  90 }
  91
  92 void
  93 DrainManager::resume()
  94 {
  95     panic_if(_state == DrainState::Running,
  96              "Trying to resume a system that is already running\n");
  97
  98     warn_if(_state == DrainState::Draining,
  99             "Resuming a system that isn't fully drained, this is untested and "
 100             "likely to break\n");
 101
 102     panic_if(_state == DrainState::Resuming,
 103              "Resuming a system that is already trying to resume. This should "
 104              "never happen.\n");
 105
 106     panic_if(_count != 0,
 107              "Resume called in the middle of a drain cycle. %u objects "
 108              "left to drain.\n", _count);
 109
 110     // At this point in time the DrainManager and all objects will be
 111     // in the the Drained state. New objects (i.e., objects created
 112     // while resuming) will inherit the Resuming state from the
 113     // DrainManager, which means we have to resume objects until all
 114     // objects are in the Running state.
 115     _state = DrainState::Resuming;
 116
 117     do {
 118         DPRINTF(Drain, "Resuming %u objects.\n", drainableCount());
 119         for (auto *obj : _allDrainable) {
 120             if (obj->drainState() != DrainState::Running) {
 121                 assert(obj->drainState() == DrainState::Drained ||
 122                        obj->drainState() == DrainState::Resuming);
 123                 obj->dmDrainResume();
 124             }
 125         }
 126     } while (!allInState(DrainState::Running));
 127
 128     _state = DrainState::Running;
 129 }
 130
 131 void
 132 DrainManager::preCheckpointRestore()
 133 {
 134     panic_if(_state != DrainState::Running,
 135              "preCheckpointRestore() called on a system that isn't in the "
 136              "Running state.\n");
 137
 138     DPRINTF(Drain, "Applying pre-restore fixes to %u objects.\n",
 139             drainableCount());
 140     _state = DrainState::Drained;
 141     for (auto *obj : _allDrainable)
 142         obj->_drainState = DrainState::Drained;
 143 }
 144
 145 void
 146 DrainManager::signalDrainDone()
 147 {
 148     assert(_count > 0);
 149     if (--_count == 0) {
 150         DPRINTF(Drain, "All %u objects drained..\n", drainableCount());
 151         exitSimLoop("Finished drain", 0);
 152     }
 153 }
 154
 155
 156 void
 157 DrainManager::registerDrainable(Drainable *obj)
 158 {
 159     std::lock_guard<std::mutex> lock(globalLock);
 160     assert(std::find(_allDrainable.begin(), _allDrainable.end(), obj) ==
 161            _allDrainable.end());
 162     _allDrainable.push_back(obj);
 163 }
 164
 165 void
 166 DrainManager::unregisterDrainable(Drainable *obj)
 167 {
 168     std::lock_guard<std::mutex> lock(globalLock);
 169     auto o = std::find(_allDrainable.begin(), _allDrainable.end(), obj);
 170     assert(o != _allDrainable.end());
 171     _allDrainable.erase(o);
 172 }
 173
 174 bool
 175 DrainManager::allInState(DrainState state) const
 176 {
 177     for (const auto *obj : _allDrainable) {
 178         if (obj->drainState() != state)
 179             return false;
 180     }
 181
 182     return true;
 183 }
 184
 185 size_t
 186 DrainManager::drainableCount() const
 187 {
 188     std::lock_guard<std::mutex> lock(globalLock);
 189     return _allDrainable.size();
 190 }
 191
 192
 193
 194 Drainable::Drainable()
 195     : _drainManager(DrainManager::instance()),
 196       _drainState(_drainManager.state())
 197 {
 198     _drainManager.registerDrainable(this);
 199 }
 200
 201 Drainable::~Drainable()
 202 {
 203     _drainManager.unregisterDrainable(this);
 204 }
 205
 206 DrainState
 207 Drainable::dmDrain()
 208 {
 209     _drainState = DrainState::Draining;
 210     _drainState = drain();
 211     assert(_drainState == DrainState::Draining ||
 212            _drainState == DrainState::Drained);
 213
 214     return _drainState;
 215 }
 216
 217 void
 218 Drainable::dmDrainResume()
 219 {
 220     panic_if(_drainState != DrainState::Drained &&
 221              _drainState != DrainState::Resuming,
 222              "Trying to resume an object that hasn't been drained\n");
 223
 224     _drainState = DrainState::Running;
 225     drainResume();
 226 }