Comment 0 for bug 217908

User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1) Gecko/20061025 Firefox/2.0 (Swiftfox)
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1) Gecko/20061025 Firefox/2.0 (Swiftfox)

Firefox caches pixmaps to X11. On a full workstation with plenty of RAM and tons of hard drive space, this probably wouldn't be seen as a bug. But when running thin clients or any type of diskless workstation this is a HUGE problem. For an example of what happens and to provide repeatability for testing here is some information.

Install Edubuntu 7.04. Boot a thin client. Install xrestop on the server. Log into client and open xrestop in a terminal. Then open Firefox while leaving xrestop visable. Browse standard less graphic intense websites and watch the cache usage as displayed by xrestop....not bad. Now hit this webpage:

http://www.carteretcountyschools.org/bms/teacherwebs/sdavenport/artgallery6.htm

You will see the X cache climb drastically until Firefox completely consumes all available RAM and Swap space at which point the client completely freezes and needs to be hard rebooted.

Now the example site above is a certain exaggeration of the problem. But it is a site that will certainly crash about every thin client system you try it on. As a workaround one can add massive amounts of RAM to the thin client (512MB+) or increase nbdswap to a very high amount (1GB+). However if a user hits the right site, the terminal will still crash. If a browser such as Opera or Konquerer are used and monitored with xrestop, you can hit the same site above and see very little increase, and a client with 128MB RAM and 32MB swap will run perfectly.

This is a bug that has apparently plagued mozilla based browsers for years and has not yet been resolved. Please remove this "feature" or at least provide a way to disable pixmap caching to X from within about:config such as "browser.cache.pixmap.enable user set boolean false". I have tried every other config option and none of them disable the pixmap caching.

Again this isn't the standard report of "Firefox is a memory hog" or "Firefox has memory leaks", etc. The problem is that Firefox caches the pixmaps at all. This simply is not able to be done on thin clients without problems. The ability to disable this feature is key to the future of thin client usage (Edubuntu, K12LTSP, LTSP in general, etc). Otherwise users of thin client systems will be forced to use alternative browsers.

Thanks,
Jim Kronebusch

Reproducible: Always

Steps to Reproduce:
1. install xrestop
2. log into client and run xrestop
3. with xrestop running browse the listed website, be sure you can see xrestop
4. watch usage of memory climb until client freezes
Actual Results:
Firefox caches all pixmaps from the currently viewed page to X until X eats all available system memory and freezes the client.

Expected Results:
Loaded the webpage with minimal system memory use.