335490 - Firefox does not free Memory if you close a Firefox Window

Status: VERIFIED INCOMPLETE

(Firefox :: General, defect)

Description

[Andreas Korthaus]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; de; rv:1.8.0.2) Gecko/20060308 Firefox/1.5.0.2
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; de; rv:1.8.0.2) Gecko/20060308 Firefox/1.5.0.2

If I had opened a couple of Firefox Windows, older Firefox versions have freed memory if I closed one of the Windows. The new Firefox does not free any memory.

Reproducible: Always

Steps to Reproduce:
1. Open many Firefox Windows with many Tabs with many images in it...
2. open Windows Task-Manager
3. Look at the Menory Usage of Firefox if you close one Firefox window after the other...

Actual Results:  
Memory Usage does not decrease

Expected Results:  
Memory usage should decrease, since you are not able to "go back" to the cached sites anyway!

Something else I run into, is that Firefox becomes really, really slow if you have opend a lot of sites with many and big images. Sometimes firefox needs 1 minute or more of 100% CPU usage to open/close a simple windows with only one image...

But it's not really easy to reproduce, because this happens only if you have visited a lot of pages with images (takes some time...). When I look at the memory usage at that time, firefox uses 300-500 MB (I have 1GB RAM installed), so it does not swap!

Here is where I noticed it last time: http://dtm.de/desktop.php

Perhaps I can find a better way to reproduce it soon!

Comment 1

[Jonathan]

Also, possibly part of same issue, ff does not reduce usage when the window is minimized, whereas IE does reduce usage significantly.

Comment 2

[Brent Newland]

Has been happening to me since the first version.

Comment 3

[Nickolay_Ponomarev]

"Firefox leaks memory after hours of usage" is not specific enough description to lead to a fix in the code, so I'm closing this bug.

There are other, more specific bugs about leaks that this bug might be a duplicate of, but we'll never know, since the scope of this bug is not well-defined.

Comment 4

[John Navas]

I object to the closing of this bug. The problem is real, properly documented, and easily reproduced.

For example, when I launch Firefox 2.0.0.3 with iGoogle as my home page, Process Explorer reports memory usage as:

   Virtual Size  103,352
   Working Set    31,264

When I then open the BBC World News RSS feed in tabs, memory usage increases to:

   Virtual Size  139,224
   Working Set    65,976

Closing all tabs but one, and directing that tab to my iGoogle home page (restoring Firefox to what it was when launched) results in very little release of memory:

   Virtual Size  136,224
   Working Set    52,704

This easily verifies the description of this bug.

It's not a memory leak, it's a failure to release unneeded memory.

Comment 5

[Nickolay_Ponomarev]

The original report doesn't have specific steps to reproduce, neither does yours (iGoogle serves different pages to everyone, "BBC World News RSS feed" is not a specific URL, etc).

Furthermore, the numbers from the Task manager may or may not indicate a memory leak. Firefox is a complicated system, with multiple caches and GC (meaning that unneeded memory may not be released for a while), so we're looking for leaks indicated by special tools or for memory usage reproducibly increasing when following the steps to reproduce.

See http://dbaron.org/log/2006-01 for information on filing useful leak bugs.

> It's not a memory leak, it's a failure to release unneeded memory.
Memory leak is, by definition, "a failure to release unneeded memory".