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 13:17:40 -0700 Organization: UCLA Computer Science Department Message-ID: <537A66E4.8000301@cs.ucla.edu> References: <83a9add91p.fsf@gnu.org> <537A51C0.50008@cs.ucla.edu> <83vbt1bmxt.fsf@gnu.org> <537A626A.5060506@cs.ucla.edu> <83ppj9bkol.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 1400533293 28062 80.91.229.3 (19 May 2014 21:01:33 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 19 May 2014 21:01:33 +0000 (UTC) Cc: fabrice.popineau@gmail.com, emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon May 19 23:01:26 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 1WmUgX-0002s5-23 for ged-emacs-devel@m.gmane.org; Mon, 19 May 2014 23:01:25 +0200 Original-Received: from localhost ([::1]:50105 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WmU0n-0003KD-Ra for ged-emacs-devel@m.gmane.org; Mon, 19 May 2014 16:18:17 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:48597) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WmU0e-0003D1-97 for emacs-devel@gnu.org; Mon, 19 May 2014 16:18:15 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WmU0W-0001O8-Q4 for emacs-devel@gnu.org; Mon, 19 May 2014 16:18:08 -0400 Original-Received: from smtp.cs.ucla.edu ([131.179.128.62]:59511) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WmU0M-0001Ld-UI; Mon, 19 May 2014 16:17:51 -0400 Original-Received: from localhost (localhost.localdomain [127.0.0.1]) by smtp.cs.ucla.edu (Postfix) with ESMTP id 26EC839E8012; Mon, 19 May 2014 13:17:49 -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 57SSFYZS+acu; Mon, 19 May 2014 13:17:40 -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 9C45939E8008; Mon, 19 May 2014 13:17:40 -0700 (PDT) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 In-Reply-To: <83ppj9bkol.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:171939 Archived-At: On 05/19/2014 01:03 PM, Eli Zaretskii wrote: > The problem, by contrast, sounds more general than that. Yes, it's a general problem with conservative garbage collection; it's why such garbage collection is called "conservative" rather than "accurate". If it's essential that GC be accurate, then Emacs shouldn't be using conservative GC. My impression, though, is that the goal is to arrange Emacs's internals so that accurate GC isn't essential. If purify-flag is a counterexample, it's almost surely simpler to change howpurify-flag works than to insist on accurate GC. What happens if you change this: (setq purify-flag nil) to something like this? (clrhash purify-flag) (setq purify-flag nil)