diff options
author | David Faure <david.faure@kdab.com> | 2013-06-21 10:32:17 +0200 |
---|---|---|
committer | The Qt Project <gerrit-noreply@qt-project.org> | 2013-08-24 13:09:46 +0200 |
commit | dacf9961da86751a59da0e84bc943fe0d1c8d95b (patch) | |
tree | 88fb959024904484ec8e7442b88c4777246a42a4 /src/corelib/thread | |
parent | 7c2a418857cd20e3e59852f0c1561a26f17d9825 (diff) |
QThreadPool: fix counting of waiting threads
QTBUG-21051 has a testcase where activeThreadCount() could actually
end up at -1 (converted to an autotest in this commit).
The reason was: start() calls tryStart() which returns false due to
too many active threads (reserveThread() causes this), so it calls
enqueueTask() - which actually wakes up the waiting thread, but
it didn't decrement the number of waiting threads.
Note that tryStart() is "if I can grab a waiting thread, enqueue task and wake it"
while start(), in case tryStart() fails, wants to "enqueue, and then if I can grab
a waiting thread, wake it". This is why enqueue shouldn't wake; waking must happen
only if we can grab a thread (d->waitingThreads > 0).
Task-number: QTBUG-21051
Change-Id: I3d98337103031c9bdf0bf365295f245be0c66aa7
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Diffstat (limited to 'src/corelib/thread')
-rw-r--r-- | src/corelib/thread/qthreadpool.cpp | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/src/corelib/thread/qthreadpool.cpp b/src/corelib/thread/qthreadpool.cpp index 31c3f5a256..9ef40a5209 100644 --- a/src/corelib/thread/qthreadpool.cpp +++ b/src/corelib/thread/qthreadpool.cpp @@ -180,6 +180,7 @@ bool QThreadPoolPrivate::tryStart(QRunnable *task) // recycle an available thread --waitingThreads; enqueueTask(task); + runnableReady.wakeOne(); return true; } @@ -218,7 +219,6 @@ void QThreadPoolPrivate::enqueueTask(QRunnable *runnable, int priority) if (it != begin && priority > (*(it - 1)).second) it = std::upper_bound(begin, --it, priority); queue.insert(it - begin, qMakePair(runnable, priority)); - runnableReady.wakeOne(); } int QThreadPoolPrivate::activeThreadCount() const @@ -456,8 +456,14 @@ void QThreadPool::start(QRunnable *runnable, int priority) Q_D(QThreadPool); QMutexLocker locker(&d->mutex); - if (!d->tryStart(runnable)) + if (!d->tryStart(runnable)) { d->enqueueTask(runnable, priority); + + if (d->waitingThreads > 0) { + --d->waitingThreads; + d->runnableReady.wakeOne(); + } + } } /*! |