760309 - maps.google.com compartment takes many collections to disappear

Status: RESOLVED WORKSFORME

(Core :: General, defect)

Description

[Gregory Szorc [:gps]]

I was looking at about:memory and noticed that a compartment for maps.google.com was lingering. With a fresh profile (read: no extensions), I noticed that when I close a maps.google.com tab, it takes 2 iterations of "minimize memory usage" in about:memory to make the compartment go away.

This is with Nightly 2012-05-30.

STR:

1) Open about:memory
2) Open https://maps.google.com/
3) Do some interaction (I don't think this really matters). I also activated WebGL maps, but the behavior is present with Google Maps Classic.
4) Close the Google Maps tab.
5) Click "Minimize memory usage" in about:memory
6) See the maps.google.com is still around taking up as much memory as it did with the active tab
7) Click "Minimize memory usage" 1 more time.
8) maps.google.com compartment disappears.

It is my understanding that a "minimize memory usage" should remove compartments from closed tabs.

On a fresh profile, I notice the compartment goes away on its own eventually. Maybe after a minute or two. However, on my main profile, the compartment has lingered for about 10 minutes after closing. There could be a separate bug there. But, I think it is related.

Comment 1

[Gregory Szorc [:gps]]

:Jesse pointed out on IRC that the "minimize memory usage" button actually performs 3 passes each time it is clicked, so updating bug summary.

Also, I notice if I constantly refresh about:memory after closing maps.google.com, the memory footprint of that compartment goes through 2 stages. The first stage (4-6s after tab close) roughly halves the memory footprint. The 2nd, about 4-6s later seems to remove the compartment. Perhaps when I am hitting "minimize memory usage" this background process has already executed and I am attributing things to the button press? I don't know what magic is happening behind the scenes.

Comment 2

[Andrew McCreight [:mccr8]]

gps, can you still reproduce this? At least using classic mode, it doesn't seem to happen for me any more.

Comment 3

[Gregory Szorc [:gps]]

I'm still seeing it. Running 2012-09-13 official Nightly on Windows 7.

1) Open maps.google.com
2) Close maps.google.com
3) Minimize memory
4) maps.google.com compartment persists
5) Minimize memory
5) maps.google.com compartment disappears

Same steps as last time.

Comment 4

[Gregory Szorc [:gps]]

I'm also seeing a ghost window for gmail. Well, at least about:memory says it is a ghost. Isn't there a write-up somewhere on how to identify the root cause of ghost windows?

Comment 5

[Andrew McCreight [:mccr8]]

Okay, I'll try again. Can you reproduce in safe mode?

As for ghost windows, if you get a cycle collector dump ( https://wiki.mozilla.org/Performance:Leak_Tools#Cycle_collector_heap_dump ) then I can use my log analysis tools to maybe figure out why it is alive. Just the smaller cc-edges-* file is needed, at least most of the time.

Comment 6

[Nicholas Nethercote [inactive]]

I can't reproduce this.  The google maps tab is disappearing from about:memory as soon as I redo "Measure" -- I don't need to "minimize memory usage" once, let alone twice.