[webkit-dev] RenderArena: Teaching an old dog new tricks

[Chris Evans]

On Thu, Nov 15, 2012 at 12:34 AM, Elliott Sprehn <esprehn at chromium.org>wrote:

>
> On Thu, Nov 15, 2012 at 3:22 AM, Chris Evans <cevans at chromium.org> wrote:
>
>>
>>> ...
>>>
>>
>> My read on the Arena is that it's fragmentation resistant (i.e. it will
>> not repurpose a larger free chunk to satisfy a smaller allocation.)
>> However, memory usage at any given time is defined by peak usage since it
>> cannot release pages back to the system without ruining its security
>> guarantee. Interestingly, it can't be super bad: we already bite this
>> bullet for RenderArena as used by RenderObjects. The RenderArena lifetime
>> is the same as the document / DOM and I was surprised to recently be told
>> that we don't throw away the RenderArena on a full layout.
>>
>>
> My understanding is that the render tree is rather small compared to the
> DOM in terms of memory usage on most pages
>

This does not seem to necessarily be the case.

Loading Gmail to the inbox view, sizes in bytes for all live allocations:
- 541k in the DOM arena
- At least a 918k plus a 49k render arena. May have failed to count a few
smaller ones that are still live.

Would you like similar measurements for a simpler page? Or some other
complicated page you think might be instructive?


Cheers
Chris

so not releasing it may not be so bad, but never releasing the memory used
> from DOM nodes seems like it'd be bad for large web apps.
>
> - E
>
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