From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: Merging scratch/no-purespace to remove unexec and purespace Date: Sun, 22 Dec 2024 10:51:39 -0500 Message-ID: References: <87zfku6ra9.fsf@gmail.com> <87seql7a3o.fsf@gmail.com> <87o71553yf.fsf@gmail.com> <87jzbsgefi.fsf@protonmail.com> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="9939"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Cc: Stefan Kangas , Helmut Eller , emacs-devel@gnu.org To: Pip Cet Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sun Dec 22 16:52:54 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 1tPOGD-0002T0-Oy for ged-emacs-devel@m.gmane-mx.org; Sun, 22 Dec 2024 16:52:53 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tPOFE-0003YX-NX; Sun, 22 Dec 2024 10:51:52 -0500 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 1tPOF8-0003YM-VP for emacs-devel@gnu.org; Sun, 22 Dec 2024 10:51:47 -0500 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tPOF6-00077X-K7 for emacs-devel@gnu.org; Sun, 22 Dec 2024 10:51:46 -0500 Original-Received: from pmg3.iro.umontreal.ca (localhost [127.0.0.1]) by pmg3.iro.umontreal.ca (Proxmox) with ESMTP id 81AF744181D; Sun, 22 Dec 2024 10:51:41 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1734882700; bh=hilmwZKZnDP7V8W4/9mVVopVQPMtngbNDW+lTm9UAtw=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=guYKFSIAQxKex6TymgGr+JZWw4B/NE3WbQt14V5fiBz9SwKYNkZjW2/bBcZlueptz pAWbYJwZdfr6Qplp/6iP4a7eCFRzY/mG+h80RwTj0jUjEbNymuwgpTOTancQG+X7Wn sCz1BCccNXbmK4HhcOSsWqkexjRo6Cu9KG5arNdShSFwwsyOZ63sJAIkZ0Z7eV4l4K v0G9M88Y7N6zu15FeXyp+fV9uRgVjgDatwPpDVZxIOVU2Y7106i6etnAe7bOhKVjHL Mrh12UpZFujJTAeFpG6BY215pKkRgwJWTYgayHFbd80yZisJpEQtmhpZn25J8BpWpg k1yi6xCLvlVUA== Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg3.iro.umontreal.ca (Proxmox) with ESMTP id 5C0A8441633; Sun, 22 Dec 2024 10:51:40 -0500 (EST) Original-Received: from asado (unknown [199.119.74.1]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 140F912032C; Sun, 22 Dec 2024 10:51:40 -0500 (EST) In-Reply-To: <87jzbsgefi.fsf@protonmail.com> (Pip Cet's message of "Sun, 22 Dec 2024 11:12:30 +0000") Received-SPF: pass client-ip=132.204.25.50; envelope-from=monnier@iro.umontreal.ca; helo=mailscanner.iro.umontreal.ca X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action 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:326859 Archived-At: > My idea is this: we add an extra mark bit area to the pdumper file for > objects which we know to be "tenured": i.e. objects that we'll treat as > immortal, but for which we also know that all referenced objects will > also be "tenured", or static. IIUC this sounds like a kind of generational GC, except that promotion to the "tenured" set is made somewhat visible instead of being 100% internal. > If we write to such an object, we clear the bit, and put it on a special > set to maintain its tenure (it'd be nicer to simply set another bit, but > non-MPS pdumper cannot do so). This should happen rarely, but it's > better than the current CHECK_IMPURE thing. If my understanding above is correct, then the `CHECK_IMPURE/check_writable` is what we usually call "write barrier", and the "special set" above is what we usually call the "remembered set". Stefan