[webkit-dev] memory leak fixes: your feedback helps......

[douchuan]

Is there convenient mem leak check tool in WebKit project?

Purushottam Sholapur 写道:
> Hi,
>
> I was facing more problem with memory leak, that too when web pages 
> have more images.
> I could find that div background images, images within div and dynamic 
> adding of div has some issue.
> For that, I have to do three changes (qt embedded +webkit 4.5 on linux)
> -------------------------
> First :
>
> For image objects, CachedResource reference count was not becoming 
> zero, even when removeChild is called.
>
> I could find that DocLoader::requestResource() is putting url and 
> image in hash, which is not cleaned properly.
>
> I have commented following two lines to solve this issue for time 
> being.(In DocLoader::requestResource())
>
> //m_docResources.set(resource->url(), resource);
> //checkCacheObjectStatus(resource);
>
> But browsing looks Ok, I do not see any issue.
>
> Can anybody tell me, what feature might break for this change. What is 
> the right fix for this.
> ------------------------
> Second:
> I had to call GarbageCollector explictly, because JSHTMLImageElement 
> objects were not getting freed in some cases.
>
> With g_timout_add, I am periodically calling garbagecollector collect 
> function.
>
> static gboolean callbackGarbageCollector(void* ptr)
> {
> if(! (JSDOMWindow::commonJSGlobalData()->heap.isBusy()))
> {
> JSLock lock(false);
> JSDOMWindow::commonJSGlobalData()->heap.collect();
> }
> return TRUE; // infinite ...
> }
>
> // Call this function only once ......
> __attribute__((visibility("default"))) void startGCTimer(int msec)
> {
> g_timeout_add(msec /*milli sec */, callbackGarbageCollector, NULL);
> }
>
> I assume there will be performce overhead, but any other issue because 
> of this.
>
> ---------------------------
> Third:
> I had to fix in our web page in javascript code.
> 1. innerHTML has to set to null ( = '';) after use.
> 2. div background images have to be set to null once they are removed.
> 3. For removeChild, We have traverse through the tree and remove each 
> child and set background image to null.
> Here is the code...
> function DeleteChildren(node){
> if(node){
> var cnt = node.childNodes.length;
> for(var x = 0; x < cnt; x++){
> var childNode = node.childNodes[0];
> if(childNode.hasChildNodes()){
> DeleteChildren(childNode);
> }
> node.removeChild(childNode);
> childNode=null;
> }
> node.style.backgroundImage = "";
> node=null;
> }
> }
> function removeElement() {
> ni = document.getElementById('myDiv');
> DeleteChildren(ni);
> ni.parentNode.removeChild(ni);
> }
> ---------------------------
>
> If there is something wrong please suggest, I am still a beginner in 
> qt+webkit.
>
> If people have seen such issues and have some fix, please share...
>
> regards
> Purush
>
>
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