Re: Heap corruption?

[Gerd Moellmann]

address@hidden (Kim F. Storm) writes:

> address@hidden (Gerd Moellmann) writes:
> 
> > There's not very much Lisp-addressable memory left on FreeBSD, and 
> > if large parts of it are used by something else...
> 
> You lost me there...   
> 
> What is "Lisp-addessable memory", and what's special about it on
> FreeBSD?

Think tag bits: an address that has a bit set that is also a tag bit
cannot be used for Lisp objects.  On FreeBSD, a process virtual memory
layout is such that Emacs can use ca. 90 Mb for Lisp objects.  After
that, addresses get too large for encoding in a Lisp_Object.

> And what do you suggest we can do about it?

One could either move the tag bits to the bottom of Lisp objects, or
reduce the number of bits being used at the top, which Stefan might be
working on, and which XEmacs has done, I think.

(IIRC, I started on the latter in the branch ``gerd_int'', but I
don't recall how far that got.)