1143912 - Excessive Memory Usage due to lots of ghost windows, with 33 extensions enabled

Status: RESOLVED INCOMPLETE

(Firefox :: Untriaged, defect)

Description

[John Smith]

Attachment: memory-report.json.gz

User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:38.0) Gecko/20100101 Firefox/38.0
Build ID: 20150315004016

Steps to reproduce:

Open a bunch of tabs, close them


Actual results:

After closing all the tabs and visiting about:memory "minimize memory usage" still using ~2GB according to Windows Task Manager


Expected results:

Should be using aprox the same amount of memory a freshly started Firefox does. Which is ~ 500MB on my profile

Comment 1

[Loic]

Do you have any add-ons installed in your profile?

If yes, could you post the list (there is a table in about:support).

Comment 2

[Nicholas Nethercote [inactive]]

The memory reports include this:

> 94 ── ghost-windows

Ghost windows are a particular kind of bad leak that are almost always caused by add-ons.

Comment 3

[John Smith]

Attachment: List of Installed Extensions

Comment 4

[John Smith]

Attachment: Another memory report taken right after starting Firefox

Comment 5

[John Smith]

Attachment: Another memory report taken after opening then closing many tabs and minimizing memory usage

Comment 6

[Nicholas Nethercote [inactive]]

33 extensions enabled... one or more are almost certainly at fault. The only way to find out is to selectively disable them, unfortunately. I suggest starting with GreaseMonkey and Stylish because they've caused similar problems in the past. Maybe YesScript, too.

Comment 7

[John Smith]

I disabled all my extensions. Now start-up usage is ~ 200 MB and after doing the above memory is ~ 1100 MB. Yet another memory report, this time with no extensions attached.

Comment 8

[John Smith]

Attachment: Memory Report with no Extensions

Comment 9

[Nickolay_Ponomarev]

The last memory report seems to indicate that the memory was freed, but not yet fully released to the OS, which is normal:

> 524.03 MB (100.0%) -- explicit
> ├──346.77 MB (66.17%) -- heap-overhead
> │  ├──318.09 MB (60.70%) ── bin-unused
> ...
> 477.77 MB (100.0%) -- decommitted
> ...
>       152.58 MB ── heap-committed
> ...
>     1,193.19 MB ── resident

I expect that if you keep using the rest of the system (not Firefox), the resident number will eventually go down, as the memory is allocated for other activities. If it doesn't go down, and the system starts swapping instead, that would be a valid bug (although hard to confirm/debug).

If you repeat the procedure again, you should end up with approximately the same resident number, not twice the current amount, which would confirm that this number by itself is not a problem. If on the other hand the resident number will keep growing with each iteration, it's also a bug, in which case we'll need more specific steps to reproduce.

Comment 10

[Paul Pasca[Away. Please needinfo? Paul Oiegas [:pauloiegasSV]]]

Since the reporter didn't provide any information requested by Nickolay, I will mark this issue as RESOLVED INCOMPLETE. If you encounter this issue again, please feel free to reopen this bug or file a new one.