[webkit-dev] DocumentLoader::m_mainResourceData seems no need

[Pavel Feldman]

On Tue, Aug 16, 2011 at 12:44 PM, Xianzhu Wang <phnixwxz at gmail.com> wrote:

>
>
> On Tue, Aug 16, 2011 at 3:41 PM, Pavel Feldman <pfeldman at chromium.org>wrote:
>
>> On Tue, Aug 16, 2011 at 11:20 AM, Xianzhu Wang <phnixwxz at gmail.com>wrote:
>>
>>> Hi,
>>>
>>> I found that DocumentLoader will hold m_mainResourceData during its whole
>>> life. I'm wondering if this is necessary. I searched all callers of
>>> DocumentLoader::mainResourceData() and DocumentLoader::mainResource() and
>>> they seem all called before or just after the document is loaded.
>>>
>>
>> This is not the case for the inspector and a number of other usages I can
>> see here:
>>
>> http://codesearch.google.com/codesearch#search/&exact_package=chromium&q=mainResourceData%5C(%5C)&type=cs
>>
>
> Thanks. I missed some cases (like WebKit2 and WebDataSource ones) as I only
> searched the compiled files in my environment. And I did overlooked the
> first case in inspector.
>
>
>> "just after" might be problematic to define as well.
>>
>
> I meant "just after" that the function is called from somewhere
> xxxDidFinishLoading() etc. For these cases, by carefully adjust the
> sequence, we can let them depend on DocumentLoader::m_mainResourceLoader
> instead of m_mainResourceData.
>
> An (maybe incomplete) list of cases that might use
> DocumentLoader::mainResourceData() after loading is:
>   WebDataSource::data()
>   WebKit::WebFrame::source()
>   WebKit::WebPage::getMainResourceDataOfFrame()
>   InspectorPageAgent::resourceContent()
>
> As the amount of memory saved by removing m_mainResourceData could be
> significant on mobile devices, for these cases I think it might be
> reasonable to have some constraints on particular platforms. For example,
> use an alternative way like fetching from cache, reloading, etc., or simply
> don't support them.
>
>
See https://bugs.webkit.org/show_bug.cgi?id=49246 as a relevant request.


>
>> Regards
>> Pavel
>>
>>  If we remove DocumentLoader::m_mainResourceData, the main resource data
>>> could be freed if there is no other references (seems true if the page is
>>> not inspected) and will save memory.
>>>
>>> I tried to removing DocumentLoader::m_mainResourceData and run all layout
>>> tests in chromium-linux. I got 6 text mismatches and 1 timeout and will
>>> investigate the failures.
>>>
>>> However, can anyone describe the original intent of
>>> DocumentLoader::m_mainResourceData? What's the case that it is used after
>>> the document is loaded?
>>>
>>> Thanks,
>>> Xianzhu
>>>
>>>
>>> _______________________________________________
>>> webkit-dev mailing list
>>> webkit-dev at lists.webkit.org
>>> http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
>>>
>>>
>>
>
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