686875 - SVG image doc uses too much style system memory

Status: NEW

(Core :: CSS Parsing and Computation, defect)

Description

[Kyle Huey (Exited; not receiving bugmail, old account, do not use)]

1. Load https://tbpl.mozilla.org/images/closebutton-dark.svg
2. Check about:memory
3. See that this doc is using 600K of styledata memory.

Comment 1

[Boris Zbarsky [:bzbarsky]]

Is this with more reporters than there were about a week ago?  Because my opt build shows u using about 75KB on styledata on this SVG.  Which is similar to how much data we use for about:blank, unsurprisingly.  All of that is due to ua.css, of course.

Comment 2

[Kyle Huey (Exited; not receiving bugmail, old account, do not use)]

This is with Tuesday's stock nightly which AFAIK has no new reporters.

I am on Windows ... if that might matter.

Comment 3

[Boris Zbarsky [:bzbarsky]]

OK, just tried this in today's stock Mac nightly, with a clean profile.


│   └────108,224 B (00.18%) -- shell(https://tbpl.mozilla.org/images/closebutton-dark.svg)
│        ├───74,368 B (00.12%) -- styledata

Granted, on Mac, so in a 64-bit build.  I have a really hard time believing that we're really using 8-9x as much memory there in a Windows 32-bit build.

Just to make sure, this is a clean profile, no extensions, no huge userContent.css?

Comment 4

[Kyle Huey (Exited; not receiving bugmail, old account, do not use)]

(In reply to Boris Zbarsky (:bz) from comment #3)
> Just to make sure, this is a clean profile, no extensions, no huge
> userContent.css?

No, it's not actually.  I can't reproduce this in a clean profile.

Comment 5

[Boris Zbarsky [:bzbarsky]]

Alright!  So what's different about your profile?  This seems worth figuring out....

Comment 6

[Kyle Huey (Exited; not receiving bugmail, old account, do not use)]

I have Adblock Plus installed.

Not sure what we can do here other than share stuff between documents or something similar.

Comment 7

[Boris Zbarsky [:bzbarsky]]

The amount of memory used by styledata (as measured by our current reporter) essentially depends on the number of selectors used in the stylesheets....  So yeah, either fewer selectors or more sharing of some sort.  This last is complicated by the fact that the cascade really does need to be different for different documents, in general.

Comment 8

[Wladimir Palant]

Which selectors count here? I guess that selectors in @-moz-document limited to another domain don't count? If so, we are currently talking about roughly 4500 selectors in EasyList. Unfortunately, finding the ones that are no longer useful is non-trivial. A solution is planned but might take a while to implement.

Comment 9

[Boris Zbarsky [:bzbarsky]]

> I guess that selectors in @-moz-document limited to another domain don't count?

I believe that is correct.