Add indicator for ghost windows to frame

[whimboo]

With the both bugs fixed we could have an indicator for ghost windows in the widget:

https://bugzilla.mozilla.org/show_bug.cgi?id=738624 - Add ghost windows to about:compartments https://bugzilla.mozilla.org/show_bug.cgi?id=738011 - Add ghost windows to about:memory

@jlebar, would you mind giving us some more background on it? I assume those entries are zombie compartments across all the opened windows and not only the current one, right?

[jlebar]

Please have a look at the ghost windows section of http://blog.mozilla.com/nnethercote/2012/04/04/memshrink-progress-week-42/

I assume those entries are zombie compartments across all the opened windows and not only the current one, right?

Sorry, I don't know what you mean. Could you rephrase that?

[whimboo]

Seems like I missed a part on that blog post. It's clear now. So it's for real ChromeWindows and not content DOMWindows.

[jlebar]

So it's for real ChromeWindows and not content DOMWindows.

I don't know exactly what you mean, but I don't think it's correct. Chrome windows usually don't show up as ghost windows...

A ghost window is a likely leak. There may be leaked windows which aren't ghosts, and there may be ghosts which aren't leaks.

[whimboo]

I don't know exactly what you mean, but I don't think it's correct. Chrome windows usually don't show up as ghost windows...

With ChromeWindow I meant the top-level windows which is visible as real windows to the user. That means a ghost window correlates to tab's content window?

[jlebar]

That means a ghost window correlates to tab's content window?

Yes, a ghost window is usually created from content, like http://facebook.com.

A ghost window may be from a top-level content window -- corresponding to the URL in the address bar -- or it may be from an iframe or popup window.

[whimboo]

Alright. So one last question: It doesn't matter how many top-level windows and tabs in each you have open, the number of ghost windows shown will span over all of those top-level windows, right?

[jlebar]

Alright. So one last question: It doesn't matter how many top-level windows and tabs in each you have open, the number of ghost windows shown will span over all of those top-level windows, right?

Yes, ghost windows are a truly global count.

[xabolcs]

FYI, from #223.

@amccreight commented 5 hours ago

... I'm not sure if it is possible right now for an addon to check these easily, but it should be easy to add something to Firefox to allow that.

[xabolcs]

FYI.

var memSrv = Components.classes["@mozilla.org/memory-reporter-manager;1"].getService(Components.interfaces.nsIMemoryReporterManager);
> undefined
memSrv.ghostWindows;
> 0

[amccreight]

Great, thanks for looking that up!