From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: MPS signals and Emacs Date: Mon, 22 Apr 2024 12:41:11 +0300 Message-ID: <86sezd68g8.fsf@gnu.org> References: <878r16n5jl.fsf@gmail.com> <87ttjulb16.fsf@gmail.com> <86a5ll7wj9.fsf@gnu.org> <71431fc4-2ab2-4778-88df-25d4e315d737@cs.ucla.edu> <00fec231-a625-406e-a51b-cb66710c6482@cs.ucla.edu> <86wmop6cot.fsf@gnu.org> <86v8496ajl.fsf@gnu.org> <86ttjt69i2.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="35591"; mail-complaints-to="usenet@ciao.gmane.io" Cc: eggert@cs.ucla.edu, eller.helmut@gmail.com, emacs-devel@gnu.org To: Gerd =?utf-8?Q?M=C3=B6llmann?= Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Mon Apr 22 11:42:09 2024 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1ryqBc-00096q-W3 for ged-emacs-devel@m.gmane-mx.org; Mon, 22 Apr 2024 11:42:09 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ryqAr-0005Gk-Rc; Mon, 22 Apr 2024 05:41:21 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ryqAo-0005Eb-WC for emacs-devel@gnu.org; Mon, 22 Apr 2024 05:41:19 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ryqAn-0003df-RJ; Mon, 22 Apr 2024 05:41:17 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=MIME-version:References:Subject:In-Reply-To:To:From: Date; bh=mzQE/47K+VDMirArB+CFdybaoOicSqmy3+MvyltMod4=; b=R2qcdIojPssnvq+A+W9F TtRSzPKqFr+4l8jAt5hcqavoz/1iIGE+NnP4+s2jf1ghjj8jCC1+f2WKdpnz8Ww+vderdDJdITHus Wc+2x6ZtsRXywPMs8Hxs5YzSbxFDvLYSYAxp+yG5zPOlpBpxkXtHIpzXZObkhh/0Sgyd1Abtjah6t 1iJN0+93NwKZklxL3CqrQ+9z1/t9U9ncLABidD5Hs0JS494HKbS1CHPAMn/fwEH6v2sT0cGy7KPXs UVtvk6Mw7xDm/KaF5EChWNlgmKOUsnpHomcMMub0eyhRFjJKbPWApNInLu6XHFG6CZ+r2KOqUiLTa eZyIf+akZuk/SQ==; In-Reply-To: (message from Gerd =?utf-8?Q?M?= =?utf-8?Q?=C3=B6llmann?= on Mon, 22 Apr 2024 11:29:30 +0200) X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 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-mx.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:317970 Archived-At: > From: Gerd Möllmann > Cc: eggert@cs.ucla.edu, eller.helmut@gmail.com, emacs-devel@gnu.org > Date: Mon, 22 Apr 2024 11:29:30 +0200 > > Eli Zaretskii writes: > > >> I think I've also seen at least one other example, but I forget where > >> that was (maybe specpdl, or bytecode?). I think the function called > >> is mark_mem or so. > > > > So any Lisp object referenced from the C stack or from byte-code will > > not be copied by MPS? > > Yes. > > > What are the implications of that for Emacs? AFAIU, the current GC > > considers any such object as live, marks it, and doesn't collect it as > > garbage during the sweep step, but being unable to copy such an object > > means something very different for a copying GC, doesn't it? Because > > AFAIU live objects _are_ copied. > > No, it's a bit different. Being able to copy and objects being live are > orthogonal. At the heart of the mostly-copying idea is simply that > ambigupusly references aren't moved in memory (so they aren't copied). > That doesn't mean these objects aren't live. They are. Doesn't copying GC work by copying live objects to a new memory region, and then freeing the old region? If so, if some objects cannot be moved, how can the old region be freed?