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Fix crashes when loading large .qmlproject's (Mac OS X)

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There is a hard limit on the number of file handles that can be open at one point per process on Mac OS X (e.g. it's 2560 on Mac OS X Snow Leopard Server, as shown by ulimit -a). Opening one or several .qmlproject's with a large number of directories to watch easily exceeds this. The results are crashes later on, e.g. when threads cannot be created any more.

This patch implements a heuristic that the file system watcher used for .qmlproject files never uses more than half the number of available file handles. It also increases the number from rlim_cur to rlim_max - the old code in main.cpp failed, see last section in

 http://developer.apple.com/maac/library/documentation/Darwin/Reference/ManPages/man2/setrlimit.2.html

for details.

Reviewed-by: ckamm
Task-number: QTCREATORBUG-1487
Task-number: QTCREATORBUG-1486
This commit is contained in:
Kai Koehne
2010-05-28 13:45:53 +02:00
parent 3082395c14
commit 7f1f9e14af
2 changed files with 37 additions and 1 deletions
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35
src/plugins/qmlprojectmanager/fileformat/filesystemwatcher.cpp
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@@ -72,6 +72,19 @@ void FileSystemWatcher::addFile(const QString &file)
addFiles(QStringList(file));
}
#ifdef Q_OS_MAC
// Returns upper limit of file handles that can be opened by this process at once. Exceeding it will probably result in crashes!
static rlim_t getFileLimit()
{
struct rlimit rl;
getrlimit(RLIMIT_NOFILE, &rl);
return rl.rlim_cur;
}
#endif
void FileSystemWatcher::addFiles(const QStringList &files)
{
QStringList toAdd;
@@ -84,6 +97,17 @@ void FileSystemWatcher::addFiles(const QStringList &files)
qWarning() << "FileSystemWatcher: File" << file << "is already being watched";
continue;
}
#ifdef Q_OS_MAC
static rlim_t maxFileOpen = getFileLimit();
// We're potentially watching a _lot_ of directories. This might crash qtcreator when we hit the upper limit.
// Heuristic is therefore: Don't use more than half of the file handles available in this watcher
if ((rlim_t)m_directories.size() + (rlim_t)m_files.size() > maxFileOpen / 2) {
qWarning() << "File" << file << "is not watched: Too many file handles are already open (max is" << maxFileOpen;
break;
}
#endif
m_files.append(file);
const int count = ++m_fileCount[file];
@@ -149,6 +173,17 @@ void FileSystemWatcher::addDirectories(const QStringList &directories)
qWarning() << "Directory" << directory << "is already being watched";
continue;
}
#ifdef Q_OS_MAC
static rlim_t maxFileOpen = getFileLimit();
// We're potentially watching a _lot_ of directories. This might crash qtcreator when we hit the upper limit.
// Heuristic is therefore: Don't use more than half of the file handles available in this watcher
if ((rlim_t)m_directories.size() + (rlim_t)m_files.size() > maxFileOpen / 2) {
qWarning() << "Directory" << directory << "is not watched: Too many file handles are already open (max is" << maxFileOpen;
break;
}
#endif
m_directories.append(directory);
const int count = ++m_directoryCount[directory];