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

Xianzhu Wang phnixwxz at gmail.com
Tue Aug 16 01:44:42 PDT 2011

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:

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.

> 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
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.webkit.org/pipermail/webkit-dev/attachments/20110816/aff69d11/attachment.html>

More information about the webkit-dev mailing list