From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.help Subject: Re: Question about memory usage Date: Tue, 03 Apr 2018 17:18:39 -0400 Message-ID: References: <83sh8c6byb.fsf@gnu.org> <690641bc-fc49-922a-26bd-6f92322d0cc0@zoho.com> <83po3g40c3.fsf@gnu.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: blaine.gmane.org 1522790447 25857 195.159.176.226 (3 Apr 2018 21:20:47 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 3 Apr 2018 21:20:47 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Tue Apr 03 23:20:43 2018 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1f3TM6-0006Xy-LJ for geh-help-gnu-emacs@m.gmane.org; Tue, 03 Apr 2018 23:20:38 +0200 Original-Received: from localhost ([::1]:37218 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f3TOC-0004Lb-3Q for geh-help-gnu-emacs@m.gmane.org; Tue, 03 Apr 2018 17:22:48 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:37942) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f3TNk-0004Kq-6N for help-gnu-emacs@gnu.org; Tue, 03 Apr 2018 17:22:20 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f3TNg-0005WF-8R for help-gnu-emacs@gnu.org; Tue, 03 Apr 2018 17:22:20 -0400 Original-Received: from [195.159.176.226] (port=49557 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1f3TNg-0005Ur-1D for help-gnu-emacs@gnu.org; Tue, 03 Apr 2018 17:22:16 -0400 Original-Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1f3TLY-0005nY-4p for help-gnu-emacs@gnu.org; Tue, 03 Apr 2018 23:20:04 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 12 Original-X-Complaints-To: usenet@blaine.gmane.org Cancel-Lock: sha1:I0yFzwo4iw81TEhiQrMKeMBranA= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 195.159.176.226 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "help-gnu-emacs" Xref: news.gmane.org gmane.emacs.help:116329 Archived-At: >> But shouldn't Emacs reuse the memory from previous loop iteration >> instead of allocating it? > That depends on the heap fragmentation and the efficiency of the > memory allocating functions to deal with fragmentation. The elements of buffer-undo-list in this case are just cons cells (and immediate integers and nil), IIUC so I don't see why fragmentation would get in the way: the previous cons-cell of the buffer-undo-list of the previous iterations, reclaimed by the GC, should be readily reusable. Stefan