[webkit-help] cached scripts leak in C Loop Interpreter mode

Baldeva, Arpit abaldeva at ea.com
Wed Apr 9 17:46:48 PDT 2014


I am using WebCore::gcController().discardAllCompiledCode() API to discard cached scripts and free up memory. This works pretty well in the JIT mode. However, when I used C Loop interpreter, the cached scripts are not discarded. So far, I have traced it down to JSC::SourceCode::m_provider member. The ref count on this member is all wrong.

The reproduction is pretty simple. Load a "hello world" type page in web view, then go to Google.com. That causes about 0.189 MB worth of scripts to get cached. Go back to the hello world page and now call WebCore::gcController().discardAllCompiledCode(). The JIT path is able to get rid of the cached scripts. However, C loop interpreter leaks pretty much everything (the ref count on the member noted about is around ~850 whereas it should be 1). The direct url of the problematic script is http://www.google.com/xjs/_/js/k=xjs.hp.en_US.75bv2nh_qxI.O/m=sb_he,pcc/rt=j/d=1/sv=1/rs=AItRSTOX5WMsAVpkgEafYeVKZ7ZCJdNXcg

An even more accessible scenario is just keep on reloading the sunspider test suite. I used 0.9.1 - http://www.webkit.org/perf/sunspider-0.9.1/sunspider-0.9.1/driver.html Every reload is pretty much leaking causing the memory usage to grow unbounded. The C Loop interpreter path memory usage goes up to 200 MB just within few minutes however the JIT path stays around 12 MB.

My version of code is about 5 months old (157437). However, I did not see any leak fixes going in recently when I search bugzilla.

Any help is appreciated.


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