And, free is atomic (at least, TMK all a good implementation does is remove something from a data structure, unless it's the last part in which case it also needs to mark that memory as free). The downside? While GC advocates will often amaze you with the fact that malloc is not an atomic operation (it has a lot of work to allocate, more or less depending on the current situation of your memory chunks and the free memory on the system), malloc is still not nearly as costly as a garbage collection cycle. It becomes especially bad when you move into swap space ). This is one of the things that makes garbage collections noticeable if a lot has happened since the last one (it's gotta move a lot of RAM and change a bunch of links to said RAM). Some Garbage Collectors (most) actually move objects to condense them in memory. So guess what? Firefox' memory usage remains exactly the same. But it still has some stuff in that block.

The OS changes it tables around for that block to indicate so.

Well, it does a couple more allocations, some fairly permanent ones, and these get put in the newest block of memory. None have enough room for the single large allocation it needs so the OS sets aside a new chunk of memory for the firefox process. You've got 20MB allocated already, all in 3 chunks. An operating systems class might help you understand why memory usage meters are completely unresponsive in the down direction.įirefox allocates memory for a rendered page.

Firefox flash plugin memory leak