105080 - Leaks when closing windows

Status: RESOLVED INVALID

(Core :: XUL, defect)

Description

[scottputterman]

I couldn't see this on the list of open windows bugs and don't know who this
should be assigned to or if this is working as expected.

I use a lot of windows throughout the course of the day and have noticed that my
memory usage as measured through the Windows task manager goes up pretty high.

Here are some steps to show what I'm seeing:

1.  Open 10 browser windows.  I used about:blank
2.  watch the task manager go up 20MB
3.  Close all 10 windows.
4.  only about 6MB is regained.  It looks like we leaked 14MB.

The interesting thing is that if I repeat the process, I only gain 10 MB on
opening (though when I close them I only regain 3MB)

Anyway, my point being that someone who opens and closes a lot of windows is
going to watch their footprint rise pretty quicklky throughout the day.

Comment 1

[Cathleen]

-> dbaron

dbaron, can you take a look at this?

Comment 2

[scottputterman]

I recognize this is a pretty general bug and that it's quite possibly expected
behavior or it might just be all of the leaks we already know about.  But, if
footprint is really a big deal then I think this bug needs to be addressed. 
Over the course of every day of using the browser, mail, and IM my memory usages
gets close to 100MB.  I'm opening and shutting windows all day long. 

Comment 3

[scottputterman]

this is the bug I mentioned in Thursday's perf meeting.

Comment 4

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

FWIW, task manager isn't the most reliable measurement of how much memory we're
using, partly since I think it ignores memory that is paged out, and minimizing
programs can affect that.  Or something like that...

Comment 5

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Bug 109671 could be a major part of the problem here.

Comment 6

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

jrgm wrote on bug 109671:
> I have a test that opens and times 100 windows, some opened singly,
> some in groups of three, and some 10 at a time. After running this 
> test with dbaron's leak fix, task manager on win2k reports that I'm 
> using 23.8MB (26.6MB peak). By comparison, without the fix, I use
> 44.3MB (46.0MB peak). Gee. A mere 20MB savings. Is that all :-]

Comment 7

[scottputterman]

That's great.  I can't wait to try this out.  Were only browser windows affected 
by this or all windows in general?

Comment 8

[John Morrison]

The change was generic to the construction of XUL documents, so potentially
there are other places where this stops a leak. However, I went through the 
process of creating an IMAP account, logging in, reading some mail and 
composing and sending a message and I didn't note a difference in memory 
usage with and without the patch. But it really depends on the situation (i.e.,
a slight change in the way I used the mail window might have triggered the 
leak).

Comment 9

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Is this good enough now?  Should I resolve it or give it to cathleen?  Do we
have anybody measuring this type of thing regularly?

Comment 10

[Rafael Ebron (:rebron)]

adt:nsbeta1-

Comment 11

[Jesse Ruderman]

Invalid: we've done a lot to decrease memory use and leaks since this bug was last touched, and plenty of people test Firefox by opening and closing windows.

Comment 12

[Worcester12345]

Bug 102229 – DNS Service and DNS Lookups leak at shutdown