[gclist] What wrong with the GC in xemacs

Erik Naggum erik@naggum.no
13 Apr 1996 20:24:34 UT


|   A cynic would ask what's so great about GC? :-)

no, a cynic would ask why people like to show off their ignorance.

|   Now, OK, you can't reasonably use a program whose working set is bigger
|   than available RAM, but the whole point is that even when you're _not_
|   reading your mail and the whole 200 message folder should be sitting
|   quiescent in swap, it's still getting paged in.

it isn't unless you select that buffer.  buffer space is not touched by GC
in Emacs.  it may be relocated if you kill other buffers, but that's not
quite the same thing.

|   My OS uses `traditional' explicit memory allocation, and stays up for
|   weeks (when I resist the temptation to upgrade it); my emacs is GCed to
|   ensure no leaks, and has to be shut down and restarted every fourth day
|   or so.

Emacs does not return allocated Lisp Object memory to the system.  this is
a recognized problem.  however, it is an issue of implementation, not a GC
issue.  it is not common for "traditional explicit memory allocation"
programs to return freed memory.  Emacs does return memory for buffers,
vectors, and large strings.  (I forget who corrected me on this list --
thanks.)  the jury is still out on the issue of whether explicit memory
allocation the like of malloc/free wastes more or less memory than GC.

#<Erik>