Variable: search-ring-max
search-ring-max is a customizable variable defined in isearch.el.gz.
Value
16
Documentation
Maximum length of search ring before oldest elements are thrown away.
Source Code
;; Defined in /usr/src/emacs/lisp/isearch.el.gz
(defcustom search-ring-max 16
"Maximum length of search ring before oldest elements are thrown away."
:type 'integer)