From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: When should ralloc.c be used? Date: Mon, 24 Oct 2016 10:12:27 -0400 Message-ID: References: <7baa18d4-2b09-caa8-005e-29008a383ad1@cs.ucla.edu> <83mvhwrgd5.fsf@gnu.org> <8539f38f-9a11-44c3-4de7-bb974c96206c@cs.ucla.edu> <838ttfnmev.fsf@gnu.org> <837f8znk8f.fsf@gnu.org> <83zilvm2ud.fsf@gnu.org> <83r377m0i8.fsf@gnu.org> <83eg36n6v5.fsf@gnu.org> <83shrl523p.fsf@gnu.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: blaine.gmane.org 1477320466 15614 195.159.176.226 (24 Oct 2016 14:47:46 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 24 Oct 2016 14:47:46 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2.50 (gnu/linux) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon Oct 24 16:47:39 2016 Return-path: Envelope-to: ged-emacs-devel@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 1bygX0-000138-Vd for ged-emacs-devel@m.gmane.org; Mon, 24 Oct 2016 16:47:19 +0200 Original-Received: from localhost ([::1]:47181 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bygX3-0003eE-8Q for ged-emacs-devel@m.gmane.org; Mon, 24 Oct 2016 10:47:21 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:52169) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1byfzv-00005T-5d for emacs-devel@gnu.org; Mon, 24 Oct 2016 10:13:07 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1byfzr-0007y3-6S for emacs-devel@gnu.org; Mon, 24 Oct 2016 10:13:07 -0400 Original-Received: from [195.159.176.226] (port=57146 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1byfzr-0007xp-03 for emacs-devel@gnu.org; Mon, 24 Oct 2016 10:13:03 -0400 Original-Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1byfzf-0001W9-9G for emacs-devel@gnu.org; Mon, 24 Oct 2016 16:12:51 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 12 Original-X-Complaints-To: usenet@blaine.gmane.org Cancel-Lock: sha1:2518OasjYqyga7lO9oddZzdU/cE= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 195.159.176.226 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:208687 Archived-At: >> But I fail to see what's hard about changing that to "rel_alloc=no, >> mmap=yes". > Why do we need mmap at all? Why not just use malloc (as implemented > by gmalloc)? AFAIU the reason we use ralloc is because of memory fragmentation, and mmap brings similar benefits. Maybe we don't need either of them, but at least at some point in the past the fragmentation issue was sufficient to convince people to write that code. Stefan