On Sat, Apr 06, 2013 at 09:11:55AM -0400, David Larochelle wrote: > Are languages that have mark and sweep garbage collection better about > returning memory to the system than languages like Perl that use reference > count garbage collection.
Not usually. On Unix systems, at least, memory is acquired from (and released to) the system using sbrk. malloc(3) and free(3) are actually front ends to sbrk. free marks memory as available to be reallocated, but only returns memory when there is enough of it at the high end of the heap. Depending on usage patterns this is unlikely to happen naturally unless memory is first compacted. This is an additional step to the garbage collection and not many languages do it AFAIK. I know Lisp can do this, but only to avoid fragmentation and does not return the memory. It is generally not necessary to return memory to the system because most modern operating systems provide a virtual view of memory so every program appears to have access to the entire memory space. Most of the time this works fine. Programs that allocate too much get swapped out when necessary. If you don't want that for your program, you can always use mlock(3) and friends. -Gyepi _______________________________________________ Boston-pm mailing list [email protected] http://mail.pm.org/mailman/listinfo/boston-pm
