LCOV - code coverage report
Current view: directory - xpcom/threads - nsThreadPool.cpp (source / functions) Found Hit Coverage
Test: app.info Lines: 160 123 76.9 %
Date: 2012-06-02 Functions: 23 15 65.2 %

       1                 : /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2                 : /* vim:set ts=2 sw=2 sts=2 et cindent: */
       3                 : /* ***** BEGIN LICENSE BLOCK *****
       4                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
       5                 :  *
       6                 :  * The contents of this file are subject to the Mozilla Public License Version
       7                 :  * 1.1 (the "License"); you may not use this file except in compliance with
       8                 :  * the License. You may obtain a copy of the License at
       9                 :  * http://www.mozilla.org/MPL/
      10                 :  *
      11                 :  * Software distributed under the License is distributed on an "AS IS" basis,
      12                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
      13                 :  * for the specific language governing rights and limitations under the
      14                 :  * License.
      15                 :  *
      16                 :  * The Original Code is Mozilla code.
      17                 :  *
      18                 :  * The Initial Developer of the Original Code is Google Inc.
      19                 :  * Portions created by the Initial Developer are Copyright (C) 2006
      20                 :  * the Initial Developer. All Rights Reserved.
      21                 :  *
      22                 :  * Contributor(s):
      23                 :  *  Darin Fisher <darin@meer.net>
      24                 :  *
      25                 :  * Alternatively, the contents of this file may be used under the terms of
      26                 :  * either the GNU General Public License Version 2 or later (the "GPL"), or
      27                 :  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
      28                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
      29                 :  * of those above. If you wish to allow use of your version of this file only
      30                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
      31                 :  * use your version of this file under the terms of the MPL, indicate your
      32                 :  * decision by deleting the provisions above and replace them with the notice
      33                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
      34                 :  * the provisions above, a recipient may use your version of this file under
      35                 :  * the terms of any one of the MPL, the GPL or the LGPL.
      36                 :  *
      37                 :  * ***** END LICENSE BLOCK ***** */
      38                 : 
      39                 : #include "nsIClassInfoImpl.h"
      40                 : #include "nsThreadPool.h"
      41                 : #include "nsThreadManager.h"
      42                 : #include "nsThread.h"
      43                 : #include "nsMemory.h"
      44                 : #include "nsAutoPtr.h"
      45                 : #include "prinrval.h"
      46                 : #include "prlog.h"
      47                 : 
      48                 : using namespace mozilla;
      49                 : 
      50                 : #ifdef PR_LOGGING
      51            1464 : static PRLogModuleInfo *sLog = PR_NewLogModule("nsThreadPool");
      52                 : #endif
      53                 : #define LOG(args) PR_LOG(sLog, PR_LOG_DEBUG, args)
      54                 : 
      55                 : // DESIGN:
      56                 : //  o  Allocate anonymous threads.
      57                 : //  o  Use nsThreadPool::Run as the main routine for each thread.
      58                 : //  o  Each thread waits on the event queue's monitor, checking for
      59                 : //     pending events and rescheduling itself as an idle thread.
      60                 : 
      61                 : #define DEFAULT_THREAD_LIMIT 4
      62                 : #define DEFAULT_IDLE_THREAD_LIMIT 1
      63                 : #define DEFAULT_IDLE_THREAD_TIMEOUT PR_SecondsToInterval(60)
      64                 : 
      65            3626 : NS_IMPL_THREADSAFE_ADDREF(nsThreadPool)
      66            5186 : NS_IMPL_THREADSAFE_RELEASE(nsThreadPool)
      67                 : NS_IMPL_CLASSINFO(nsThreadPool, NULL, nsIClassInfo::THREADSAFE,
      68                 :                   NS_THREADPOOL_CID)
      69            1880 : NS_IMPL_QUERY_INTERFACE3_CI(nsThreadPool, nsIThreadPool, nsIEventTarget,
      70               0 :                             nsIRunnable)
      71               0 : NS_IMPL_CI_INTERFACE_GETTER2(nsThreadPool, nsIThreadPool, nsIEventTarget)
      72                 : 
      73            1560 : nsThreadPool::nsThreadPool()
      74                 :   : mThreadLimit(DEFAULT_THREAD_LIMIT)
      75                 :   , mIdleThreadLimit(DEFAULT_IDLE_THREAD_LIMIT)
      76            1560 :   , mIdleThreadTimeout(DEFAULT_IDLE_THREAD_TIMEOUT)
      77                 :   , mIdleCount(0)
      78            3120 :   , mShutdown(false)
      79                 : {
      80            1560 : }
      81                 : 
      82            3120 : nsThreadPool::~nsThreadPool()
      83                 : {
      84            1560 :   Shutdown();
      85            1560 : }
      86                 : 
      87                 : nsresult
      88            1263 : nsThreadPool::PutEvent(nsIRunnable *event)
      89                 : {
      90                 :   // Avoid spawning a new thread while holding the event queue lock...
      91                 :  
      92            1263 :   bool spawnThread = false;
      93                 :   {
      94            2526 :     ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
      95                 : 
      96            1263 :     LOG(("THRD-P(%p) put [%d %d %d]\n", this, mIdleCount, mThreads.Count(),
      97                 :          mThreadLimit));
      98            1263 :     NS_ASSERTION(mIdleCount <= (PRUint32) mThreads.Count(), "oops");
      99                 : 
     100                 :     // Make sure we have a thread to service this event.
     101            1263 :     if (mIdleCount == 0 && mThreads.Count() < (PRInt32) mThreadLimit)
     102             186 :       spawnThread = true;
     103                 : 
     104            1263 :     mEvents.PutEvent(event);
     105                 :   }
     106                 : 
     107            1263 :   LOG(("THRD-P(%p) put [spawn=%d]\n", this, spawnThread));
     108            1263 :   if (!spawnThread)
     109            1077 :     return NS_OK;
     110                 : 
     111             372 :   nsCOMPtr<nsIThread> thread;
     112             186 :   nsThreadManager::get()->NewThread(0,
     113                 :                                     nsIThreadManager::DEFAULT_STACK_SIZE,
     114             186 :                                     getter_AddRefs(thread));
     115             186 :   NS_ENSURE_STATE(thread);
     116                 : 
     117             186 :   bool killThread = false;
     118                 :   {
     119             372 :     ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
     120             186 :     if (mThreads.Count() < (PRInt32) mThreadLimit) {
     121             186 :       mThreads.AppendObject(thread);
     122                 :     } else {
     123               0 :       killThread = true;  // okay, we don't need this thread anymore
     124                 :     }
     125                 :   }
     126             186 :   LOG(("THRD-P(%p) put [%p kill=%d]\n", this, thread.get(), killThread));
     127             186 :   if (killThread) {
     128               0 :     thread->Shutdown();
     129                 :   } else {
     130             186 :     thread->Dispatch(this, NS_DISPATCH_NORMAL);
     131                 :   }
     132                 : 
     133             186 :   return NS_OK;
     134                 : }
     135                 : 
     136                 : void
     137              29 : nsThreadPool::ShutdownThread(nsIThread *thread)
     138                 : {
     139              29 :   LOG(("THRD-P(%p) shutdown async [%p]\n", this, thread));
     140                 : 
     141                 :   // This method is responsible for calling Shutdown on |thread|.  This must be
     142                 :   // done from some other thread, so we use the main thread of the application.
     143                 : 
     144              29 :   NS_ASSERTION(!NS_IsMainThread(), "wrong thread");
     145                 : 
     146              58 :   nsRefPtr<nsIRunnable> r = NS_NewRunnableMethod(thread, &nsIThread::Shutdown);
     147              29 :   NS_DispatchToMainThread(r);
     148              29 : }
     149                 : 
     150                 : NS_IMETHODIMP
     151             186 : nsThreadPool::Run()
     152                 : {
     153             186 :   LOG(("THRD-P(%p) enter\n", this));
     154                 : 
     155             372 :   nsCOMPtr<nsIThread> current;
     156             186 :   nsThreadManager::get()->GetCurrentThread(getter_AddRefs(current));
     157                 : 
     158             186 :   bool shutdownThreadOnExit = false;
     159             186 :   bool exitThread = false;
     160             186 :   bool wasIdle = false;
     161                 :   PRIntervalTime idleSince;
     162                 : 
     163             372 :   nsCOMPtr<nsIThreadPoolListener> listener;
     164                 :   {
     165             372 :     ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
     166             186 :     listener = mListener;
     167                 :   }
     168                 : 
     169             186 :   if (listener) {
     170               0 :     listener->OnThreadCreated();
     171                 :   }
     172                 : 
     173            3015 :   do {
     174            6030 :     nsCOMPtr<nsIRunnable> event;
     175                 :     {
     176            6030 :       ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
     177            3015 :       if (!mEvents.GetPendingEvent(getter_AddRefs(event))) {
     178            1752 :         PRIntervalTime now     = PR_IntervalNow();
     179            1752 :         PRIntervalTime timeout = PR_MillisecondsToInterval(mIdleThreadTimeout);
     180                 : 
     181                 :         // If we are shutting down, then don't keep any idle threads
     182            1752 :         if (mShutdown) {
     183             157 :           exitThread = true;
     184                 :         } else {
     185            1595 :           if (wasIdle) {
     186                 :             // if too many idle threads or idle for too long, then bail.
     187             342 :             if (mIdleCount > mIdleThreadLimit || (now - idleSince) >= timeout)
     188               0 :               exitThread = true;
     189                 :           } else {
     190                 :             // if would be too many idle threads...
     191            1253 :             if (mIdleCount == mIdleThreadLimit) {
     192              29 :               exitThread = true;
     193                 :             } else {
     194            1224 :               ++mIdleCount;
     195            1224 :               idleSince = now;
     196            1224 :               wasIdle = true;
     197                 :             }
     198                 :           }
     199                 :         }
     200                 : 
     201            1752 :         if (exitThread) {
     202             186 :           if (wasIdle)
     203             156 :             --mIdleCount;
     204             186 :           shutdownThreadOnExit = mThreads.RemoveObject(current);
     205                 :         } else {
     206            1566 :           PRIntervalTime delta = timeout - (now - idleSince);
     207            1566 :           LOG(("THRD-P(%p) waiting [%d]\n", this, delta));
     208            1566 :           mon.Wait(delta);
     209                 :         }
     210            1263 :       } else if (wasIdle) {
     211            1068 :         wasIdle = false;
     212            1068 :         --mIdleCount;
     213                 :       }
     214                 :     }
     215            3015 :     if (event) {
     216            1263 :       LOG(("THRD-P(%p) running [%p]\n", this, event.get()));
     217            1263 :       event->Run();
     218                 :     }
     219            3015 :   } while (!exitThread);
     220                 : 
     221             186 :   if (listener) {
     222               0 :     listener->OnThreadShuttingDown();
     223                 :   }
     224                 : 
     225             186 :   if (shutdownThreadOnExit) {
     226              29 :     ShutdownThread(current);
     227                 :   }
     228                 : 
     229             186 :   LOG(("THRD-P(%p) leave\n", this));
     230             186 :   return NS_OK;
     231                 : }
     232                 : 
     233                 : NS_IMETHODIMP
     234            1266 : nsThreadPool::Dispatch(nsIRunnable *event, PRUint32 flags)
     235                 : {
     236            1266 :   LOG(("THRD-P(%p) dispatch [%p %x]\n", this, event, flags));
     237                 : 
     238            1266 :   NS_ENSURE_STATE(!mShutdown);
     239                 : 
     240            1263 :   if (flags & DISPATCH_SYNC) {
     241               0 :     nsCOMPtr<nsIThread> thread;
     242               0 :     nsThreadManager::get()->GetCurrentThread(getter_AddRefs(thread));
     243               0 :     NS_ENSURE_STATE(thread);
     244                 : 
     245                 :     nsRefPtr<nsThreadSyncDispatch> wrapper =
     246               0 :         new nsThreadSyncDispatch(thread, event);
     247               0 :     PutEvent(wrapper);
     248                 : 
     249               0 :     while (wrapper->IsPending())
     250               0 :       NS_ProcessNextEvent(thread);
     251                 :   } else {
     252            1263 :     NS_ASSERTION(flags == NS_DISPATCH_NORMAL, "unexpected dispatch flags");
     253            1263 :     PutEvent(event);
     254                 :   }
     255            1263 :   return NS_OK;
     256                 : }
     257                 : 
     258                 : NS_IMETHODIMP
     259               0 : nsThreadPool::IsOnCurrentThread(bool *result)
     260                 : {
     261                 :   // No one should be calling this method.  If this assertion gets hit, then we
     262                 :   // need to think carefully about what this method should be returning.
     263               0 :   NS_NOTREACHED("implement me");
     264                 : 
     265               0 :   *result = false;
     266               0 :   return NS_OK;
     267                 : }
     268                 : 
     269                 : NS_IMETHODIMP
     270            3120 : nsThreadPool::Shutdown()
     271                 : {
     272            6240 :   nsCOMArray<nsIThread> threads;
     273            6240 :   nsCOMPtr<nsIThreadPoolListener> listener;
     274                 :   {
     275            6240 :     ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
     276            3120 :     mShutdown = true;
     277            3120 :     mon.NotifyAll();
     278                 : 
     279            3120 :     threads.AppendObjects(mThreads);
     280            3120 :     mThreads.Clear();
     281                 : 
     282                 :     // Swap in a null listener so that we release the listener at the end of
     283                 :     // this method. The listener will be kept alive as long as the other threads
     284                 :     // that were created when it was set.
     285            3120 :     mListener.swap(listener);
     286                 :   }
     287                 : 
     288                 :   // It's important that we shutdown the threads while outside the event queue
     289                 :   // monitor.  Otherwise, we could end up dead-locking.
     290                 : 
     291            3277 :   for (PRInt32 i = 0; i < threads.Count(); ++i)
     292             157 :     threads[i]->Shutdown();
     293                 : 
     294            3120 :   return NS_OK;
     295                 : }
     296                 : 
     297                 : NS_IMETHODIMP
     298               0 : nsThreadPool::GetThreadLimit(PRUint32 *value)
     299                 : {
     300               0 :   *value = mThreadLimit;
     301               0 :   return NS_OK;
     302                 : }
     303                 : 
     304                 : NS_IMETHODIMP
     305            1560 : nsThreadPool::SetThreadLimit(PRUint32 value)
     306                 : {
     307            3120 :   ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
     308            1560 :   mThreadLimit = value;
     309            1560 :   if (mIdleThreadLimit > mThreadLimit)
     310               0 :     mIdleThreadLimit = mThreadLimit;
     311            1560 :   mon.NotifyAll();  // wake up threads so they observe this change
     312            1560 :   return NS_OK;
     313                 : }
     314                 : 
     315                 : NS_IMETHODIMP
     316               0 : nsThreadPool::GetIdleThreadLimit(PRUint32 *value)
     317                 : {
     318               0 :   *value = mIdleThreadLimit;
     319               0 :   return NS_OK;
     320                 : }
     321                 : 
     322                 : NS_IMETHODIMP
     323            1560 : nsThreadPool::SetIdleThreadLimit(PRUint32 value)
     324                 : {
     325            3120 :   ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
     326            1560 :   mIdleThreadLimit = value;
     327            1560 :   if (mIdleThreadLimit > mThreadLimit)
     328            1426 :     mIdleThreadLimit = mThreadLimit;
     329            1560 :   mon.NotifyAll();  // wake up threads so they observe this change
     330            1560 :   return NS_OK;
     331                 : }
     332                 : 
     333                 : NS_IMETHODIMP
     334               0 : nsThreadPool::GetIdleThreadTimeout(PRUint32 *value)
     335                 : {
     336               0 :   *value = mIdleThreadTimeout;
     337               0 :   return NS_OK;
     338                 : }
     339                 : 
     340                 : NS_IMETHODIMP
     341            1560 : nsThreadPool::SetIdleThreadTimeout(PRUint32 value)
     342                 : {
     343            3120 :   ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
     344            1560 :   mIdleThreadTimeout = value;
     345            1560 :   mon.NotifyAll();  // wake up threads so they observe this change
     346            1560 :   return NS_OK;
     347                 : }
     348                 : 
     349                 : NS_IMETHODIMP
     350               0 : nsThreadPool::GetListener(nsIThreadPoolListener** aListener)
     351                 : {
     352               0 :   ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
     353               0 :   NS_IF_ADDREF(*aListener = mListener);
     354               0 :   return NS_OK;
     355                 : }
     356                 : 
     357                 : NS_IMETHODIMP
     358               0 : nsThreadPool::SetListener(nsIThreadPoolListener* aListener)
     359                 : {
     360               0 :   nsCOMPtr<nsIThreadPoolListener> swappedListener(aListener);
     361                 :   {
     362               0 :     ReentrantMonitorAutoEnter mon(mEvents.GetReentrantMonitor());
     363               0 :     mListener.swap(swappedListener);
     364                 :   }
     365               0 :   return NS_OK;
     366            4392 : }

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