From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Pip Cet Newsgroups: gmane.emacs.devel Subject: Re: Opportunistic GC Date: Mon, 8 Mar 2021 09:02:52 +0000 Message-ID: References: <666da624-2f59-2eb4-8e56-f0ad20dd900c@gmx.at> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="14679"; mail-complaints-to="usenet@ciao.gmane.io" Cc: eliz@gnu.org, Stefan Monnier , emacs-devel@gnu.org To: martin rudalics Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Mon Mar 08 10:04:23 2021 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 1lJBoL-0003eb-WE for ged-emacs-devel@m.gmane-mx.org; Mon, 08 Mar 2021 10:04:22 +0100 Original-Received: from localhost ([::1]:58270 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lJBoK-00021f-V2 for ged-emacs-devel@m.gmane-mx.org; Mon, 08 Mar 2021 04:04:20 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:47864) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lJBnZ-0001b5-Am for emacs-devel@gnu.org; Mon, 08 Mar 2021 04:03:33 -0500 Original-Received: from mail-ot1-x32f.google.com ([2607:f8b0:4864:20::32f]:44430) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lJBnX-0000E4-UH; Mon, 08 Mar 2021 04:03:33 -0500 Original-Received: by mail-ot1-x32f.google.com with SMTP id f33so8453157otf.11; Mon, 08 Mar 2021 01:03:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ql0KEe6TRla8646dQ7B3isNr+t/u7vYPN1wk0qHCBhM=; b=puliqBaDtArkTQ90juMeDT56Ztrlvb662jRoc7vDm0J6G5AizPiwZ20GlhBH1P7ZKk FUe1hMjU1UrppdZ1OyVd6hiyk314MyT0AxdCPRgaBcgNSFtxKhe/opI9oOcC/OGTJbPJ qGYob6Vhp/GxoO4Re2WQB+N2BWhIviUodyJ3t7O055G5wOzvd2kQMuQZ92qyl5sj/9iB jFpHaiGcjfQpFAjpwnFCAliicgV8/LK67BUift7VjzH24lKMgwaX500prOsC5LcOS5no mk2//fcEz4OF6jilJ9pddT/fLP9GULHl/Yws4vytYlcKzfZ4xlCz9vTeJ612kZsFLRRG djIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ql0KEe6TRla8646dQ7B3isNr+t/u7vYPN1wk0qHCBhM=; b=SrK2gW3EDXDon38Ze51Y7r2plmDq1ZlHA6wK4nxWnMgdv1LBD2Tbp7ArobzxvvjJvg IXxoH4OefiaDLdnvKOIEtp5CeYq7w9mxG27uwX6NG6WxHzvNE7gdmcpbb/oT285RkUF6 WQ3IorUpRonYb/N7lP98uK1PICveXSzqPJrpfVlK20V3aleJo50AtR38BUNKuJCI2hhe ZrDOaawJNOIv7iXuVHfovRc3nEx9PG0VXJun/0H/+osFx7XbHsunhXdmnHlpz0v9ELZI imHQAGJ7dPD2F77psedVGRxg28InDJKa8DaKKVHz6xYV4xpaPEzPUKC5eHzntkY7pJqD gQvg== X-Gm-Message-State: AOAM532AXA4jHXQLFwRlXw9YeqTp8EjJBIbJWaAV9IqNiyefUVVzsOH4 iGka1Nj2hi6i+bUk4F7jN4LcjwtDY8h42vXeQX8= X-Google-Smtp-Source: ABdhPJw4TbqE0TQ9qkS6Rt3fL29yQpFcVj9XOIgODdppRfjcWOU1MDGfT04nppzKVMrV+qtBQbyZhkRN8YviJaCS0KM= X-Received: by 2002:a05:6830:1011:: with SMTP id a17mr16729971otp.154.1615194209373; Mon, 08 Mar 2021 01:03:29 -0800 (PST) In-Reply-To: <666da624-2f59-2eb4-8e56-f0ad20dd900c@gmx.at> Received-SPF: pass client-ip=2607:f8b0:4864:20::32f; envelope-from=pipcet@gmail.com; helo=mail-ot1-x32f.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, 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: 2.1.23 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" Xref: news.gmane.io gmane.emacs.devel:266165 Archived-At: On Mon, Mar 8, 2021 at 8:26 AM martin rudalics wrote: > > For me, it was a bit difficult to see that this would indeed be safe, > > but I'm now pretty convinced it would be: objects that are unreachable > > in the child Emacs cannot become reachable in the parent Emacs (they > > might show up on the stack, but that's a false positive). > > How would this handle the standard problem of the Lisp thread storing a > pointer to an unmarked object A in an already marked object B and > releasing all other pointers to A? We fork(), we don't clone(). If A exists at the time of fork() but isn't reachable through the thread's stack, that's a bug anyway; if it doesn't exist yet at the time of fork(), it's not collected in this cycle. Did I miss something? (Other than weak hash tables, of course, which may resurrect unreachable objects, but I intend to handle those...) Pip