59.6 Running out of Memory
If you get the error message ‘Virtual memory exceeded’, save
your modified buffers with C-x s. This method of saving them
has the smallest need for additional memory. Emacs keeps a reserve of
memory which it makes available when this error happens; that should
be enough to enable C-x s to complete its work. When the
reserve has been used, ‘!MEM FULL!’ appears at the beginning of
the mode line, indicating there is no more reserve.
Once you have saved your modified buffers, you can exit this Emacs
session and start another, or you can use M-x kill-some-buffers
to free space in the current Emacs job. If this frees up sufficient
space, Emacs will refill its memory reserve, and ‘!MEM FULL!’
will disappear from the mode line. That means you can safely go on
editing in the same Emacs session.
Do not use M-x buffer-menu to save or kill buffers when you run
out of memory, because the buffer menu needs a fair amount of memory
itself, and the reserve supply may not be enough.