[webkit-qt] Memory Leak in QtWebKit

chen mihua chenmh at cn.fujitsu.com
Wed Feb 29 18:18:18 PST 2012

Dear Alexis

Thanks for your reply in such a quick.

Actually I have ever checked this problem in Qt 4.7.3、Qt 4.7.4 and Qt 4.8,  and it
remains the same in all these versions.  After that I decided to come to this place
to find some help.


Eric Chen

On 2012年03月01日 10:04, Alexis Menard wrote:
> On Wed, Feb 29, 2012 at 10:57 PM, chen mihua<chenmh at cn.fujitsu.com>  wrote:
>> Dear Alexis
>> Thanks for your reply.
>> It is correct that OS will free all allocated memory when the program is
>> closed, however, this will
>> not help us, because we want our program to run continuously after the
>> device is powered on.
>> The program has multi tab feature, so construction and destruction of
>> webview objects will happen
>> frequently in our scenario.
> Ah that is something else. You were talking about the all program in
> your original mail. Now yes deleting views should not leak I agree.
>> So it would be a problem if memory leak happens after every destruction of
>> webview object.
>> Don't you agree this?
> Agree.
>> You have mentioned that it is faster to free leaking memory by OS , but in
>> my view a program is
>> responsible for doing cleanup work by itself and never depends OS to do it.
>> So I want to figure out the real reason why webkit is designed like this?
>>   Can you provide some
>> information about this?
> I need to investigate. Maybe it is fixed since the version of Qt 4.8
> Could you try to compile a webkit trunk to see?
>> Best Regards
>> Eric Chen
>> On 2012年02月29日 19:17, Alexis Menard wrote:
>>> On Wed, Feb 29, 2012 at 12:53 AM, 陳敏華<chenmh at cn.fujitsu.com>   wrote:
>>>> Dear all
>>>> I'd like to ask you question about memory leak in Webkit. Currently, I am
>>>> using
>>>> QtWebkit self contained in Qt 4.8.0, and my test application is like
>>>> follows:
>>>> int main(int argc, char *argv[])
>>>> {
>>>>     QApplication a(argc, argv);
>>>>     QWebView* view = new QWebView();
>>>>     view->load(QUrl("http://www.baidu.com"));
>>>>     view->show();
>>>>     a.exec();
>>>>     delete view;
>>>>     return 0;
>>>> }
>>>> As you know, Webkit provide RefCountedLeakCounter class to detect memory
>>>> leak. When I run this test application in debug mode, I have noticed that
>>>> many WebCoreNodes and CachedResource have leaked. This leak could be a big
>>>> problem because we want to make use of WebKit in embedded device.
>>> But when the program is closed aren't the memory allocated to him
>>> freed by the OS?
>>>> So, I'd like to ask you all whether this memory leak real or not? I just
>>>> can't believe Webkit would leak memory in such a simple test, or if Webkit
>>>> provides some other mechanism to ensure memory will not be leaked, please
>>>> tell me.
>>> It happens that sometimes leaking on exit is not very bad as the OS
>>> will free the memory for you anyway. In some scenarios it is faster to
>>> do so...Now I haven't investigate myself but I know it sometimes
>>> happens. In modern OS it's not a problem, maybe on yours it is fine
>>> too. You have to check.
>>>> Can anyone provide some information about this problem? I really
>>>> appreciate your help.
>>>> Best Regards
>>>> Eric Chen
>>>> ---------------------------------------------------
>>>> Chen Minhua
>>>> Development Dept.III
>>>> Nanjing Fujitsu Nanda Software Tech. Co., Ltd.(FNST)
>>>> No. 6 Wenzhu Road, Nanjing, 210012, China
>>>> TEL: 县86630566-615
>>>> COINS: 79955-615
>>>> FAX: 县83317685
>>>> MAIL: chenmh at cn.fujitsu.com
>>>> ---------------------------------------------------
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