From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: GC and stack marking Date: Wed, 21 May 2014 20:58:19 +0300 Message-ID: <83y4xvm2tg.fsf@gnu.org> References: <83a9add91p.fsf@gnu.org> <8338g4bd7m.fsf@gnu.org> <83wqdgntan.fsf@gnu.org> <83ppj7oniv.fsf@gnu.org> <838upvnnsq.fsf@gnu.org> Reply-To: Eli Zaretskii NNTP-Posting-Host: plane.gmane.org X-Trace: ger.gmane.org 1400695116 6786 80.91.229.3 (21 May 2014 17:58:36 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 21 May 2014 17:58:36 +0000 (UTC) Cc: fabrice.popineau@gmail.com, emacs-devel@gnu.org To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed May 21 19:58:29 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 1WnAmX-0007XE-4c for ged-emacs-devel@m.gmane.org; Wed, 21 May 2014 19:58:25 +0200 Original-Received: from localhost ([::1]:32988 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WnAmW-00075u-Kl for ged-emacs-devel@m.gmane.org; Wed, 21 May 2014 13:58:24 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:47603) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WnAmO-00075V-8g for emacs-devel@gnu.org; Wed, 21 May 2014 13:58:21 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WnAmJ-0000Pa-2j for emacs-devel@gnu.org; Wed, 21 May 2014 13:58:16 -0400 Original-Received: from mtaout23.012.net.il ([80.179.55.175]:36938) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WnAmI-0000PS-QO for emacs-devel@gnu.org; Wed, 21 May 2014 13:58:10 -0400 Original-Received: from conversion-daemon.a-mtaout23.012.net.il by a-mtaout23.012.net.il (HyperSendmail v2007.08) id <0N5X00J00R1VEL00@a-mtaout23.012.net.il> for emacs-devel@gnu.org; Wed, 21 May 2014 20:58:09 +0300 (IDT) Original-Received: from HOME-C4E4A596F7 ([87.69.4.28]) by a-mtaout23.012.net.il (HyperSendmail v2007.08) with ESMTPA id <0N5X00JGYR8W9490@a-mtaout23.012.net.il>; Wed, 21 May 2014 20:58:09 +0300 (IDT) In-reply-to: X-012-Sender: halo1@inter.net.il X-detected-operating-system: by eggs.gnu.org: Solaris 10 X-Received-From: 80.179.55.175 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:172001 Archived-At: > From: Stefan Monnier > Cc: emacs-devel@gnu.org, fabrice.popineau@gmail.com > Date: Wed, 21 May 2014 13:40:21 -0400 > > > I already tried that before, and came up empty-handed. I tried again > > now; the address of that value on the stack does not correspond to any > > local variable in the corresponding stack frame, and I also cannot > > find that address in the disassembly of the function whose stack frame > > includes the value. > > It might simply be a slot that's unused by the current stack frame, > whose value comes from some stack frame that existed some time in > the past. That's probably what it is, yes. > Which stack frame is that? The one of Fgarbage_collect. That's why I asked about mark_stack looking for objects too high on the stack. > > Now, I have a question: mark_stack stops examining the stack when it > > gets to its own stack frame. That is certainly safe, but it sounds > > too conservative: it should stop at the stack frame of > > Fgarbage_collect, I think, because no live Lisp object can appear > > while Fgarbage_collect runs, right? > > Sounds right, yes. I will try that and see if that helps. Of course, if my reading of GDB data is correct, and the value was indeed in the Fgarbage_collect's stack frame, it must help.