Memory leaks have always been a problem for browsers, Firefox in particular. Mozilla has been working hard on fixing memory usage and leaks, and the results have been quite spectacular. In a year Firefox's memory usage dropped considerably.
The most egregious leaks have also been fixed. In fact, Mozilla has been focusing recently on add-ons rather than the browser as they are the cause of the biggest remaining problems.
Quite recently, Mozilla implemented a fix which prevented the most common add-on memory leaks
. This fix worked without any changes to any add-on and had a big impact. It is included in Firefox 15, slated for release later today
However, in an ironic twist, the patch to fix memory leaks actually caused other big leaks in several Greasemonkey userscripts, defeating the patch's purpose.
Thankfully, the latest update to the popular add-on, Greasemonkey 1.0, fixes this issue and the leaks that came with it.
"The scripts we know that leak are 'YousableTubeFix' and 'Textarea backup with expiry,' but others might have the same problem. Fortunately, Anthony Lieuallen and Kyle Huey worked together to fix the problem, and version 1.0 of GreaseMonkey contains the fix," Mozilla's Nicholas Nethercote who leads the MemShrink project, explained
Greasemonkey should be updated automatically, but you can force the update by going to Greasemonkey's add-on page and clicking "Add to Firefox."
When the add-on leak patch was revealed, developers warned there could be some issues with some add-ons and that the fix could actually induce leaks in some rare cases.
So far, Greasemonkey is the only add-on where this was discovered and even here with only a very few userscripts. Even here, the problem had more to do with the way the userscripts were written than anything else.
With Firefox 15 landing in a few hours, hundreds of millions of users will be a lot safer from add-on memory leaks and should find the browser more frugal and more responsive.
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