From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: GC and stack marking Date: Mon, 19 May 2014 11:47:28 -0700 Organization: UCLA Computer Science Department Message-ID: <537A51C0.50008@cs.ucla.edu> References: <83a9add91p.fsf@gnu.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1400525294 9104 80.91.229.3 (19 May 2014 18:48:14 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 19 May 2014 18:48:14 +0000 (UTC) Cc: Fabrice Popineau To: Eli Zaretskii , emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon May 19 20:48:08 2014 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1WmSbV-0001xJ-KH for ged-emacs-devel@m.gmane.org; Mon, 19 May 2014 20:48:05 +0200 Original-Received: from localhost ([::1]:49734 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WmSbV-0007k7-Ak for ged-emacs-devel@m.gmane.org; Mon, 19 May 2014 14:48:05 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:58473) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WmSbL-0007jL-QT for emacs-devel@gnu.org; Mon, 19 May 2014 14:48:01 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WmSbF-0002HL-Tt for emacs-devel@gnu.org; Mon, 19 May 2014 14:47:55 -0400 Original-Received: from smtp.cs.ucla.edu ([131.179.128.62]:54050) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WmSb9-0002EB-6c; Mon, 19 May 2014 14:47:43 -0400 Original-Received: from localhost (localhost.localdomain [127.0.0.1]) by smtp.cs.ucla.edu (Postfix) with ESMTP id DC232A6000C; Mon, 19 May 2014 11:47:33 -0700 (PDT) X-Virus-Scanned: amavisd-new at smtp.cs.ucla.edu Original-Received: from smtp.cs.ucla.edu ([127.0.0.1]) by localhost (smtp.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id EgNyC0EvoaWq; Mon, 19 May 2014 11:47:28 -0700 (PDT) Original-Received: from penguin.cs.ucla.edu (Penguin.CS.UCLA.EDU [131.179.64.200]) by smtp.cs.ucla.edu (Postfix) with ESMTPSA id B7EF9A60002; Mon, 19 May 2014 11:47:28 -0700 (PDT) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 In-Reply-To: <83a9add91p.fsf@gnu.org> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6.x X-Received-From: 131.179.128.62 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 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-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:171936 Archived-At: On 05/19/2014 09:31 AM, Eli Zaretskii wrote: > is it possible that a Lisp object which is no longer referenced by anything won't be GC'ed because it is marked by mark_stack due to some kind of coincidence? Yes. Normally Emacs uses a conservative approach, which means it occasionally does not collect something that is in fact garbage. See, for example, . > how can we make sure this hash-table indeed gets GC'd before we dump Emacs? > We could have the garbage collector treat purify-flag specially, I suppose.