From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Emanuel Berg Newsgroups: gmane.emacs.devel Subject: Re: Emacs design and architecture. How about copy-on-write? Date: Tue, 19 Sep 2023 13:14:15 +0200 Message-ID: <87zg1ixvnc.fsf@dataswamp.org> References: <83edizjn0v.fsf@gnu.org> <0518f65b-1dd1-6923-8497-da4d3aeac631@gutov.dev> <87sf7fc7kd.fsf@dataswamp.org> <834jjuk68t.fsf@gnu.org> <87cyyhc7uu.fsf@dataswamp.org> <83ttrsg9nx.fsf@gnu.org> <83h6nrg4eg.fsf@gnu.org> <83v8c7elan.fsf@gnu.org> <877conk5ny.fsf@localhost> <83ttrreeu0.fsf@gnu.org> <87bkdzeas1.fsf@localhost> <83cyyfe5l8.fsf@gnu.org> <8734zbyu6o.fsf@dataswamp.org> <835y46e8o9.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="29914"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: emacs-devel@gnu.org Cancel-Lock: sha1:5HYQaKvpkD7OgcA36ct1gPwu/YY= Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Tue Sep 19 14:14:42 2023 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 1qiZco-0007YU-2z for ged-emacs-devel@m.gmane-mx.org; Tue, 19 Sep 2023 14:14:42 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qiZbf-0008Hb-LX; Tue, 19 Sep 2023 08:13:31 -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 1qiYgU-0002pg-56 for emacs-devel@gnu.org; Tue, 19 Sep 2023 07:14:26 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qiYgS-0005ME-Gd for emacs-devel@gnu.org; Tue, 19 Sep 2023 07:14:25 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1qiYgP-0009KF-Ve for emacs-devel@gnu.org; Tue, 19 Sep 2023 13:14:21 +0200 X-Injected-Via-Gmane: http://gmane.org/ Mail-Followup-To: emacs-devel@gnu.org Mail-Copies-To: never Received-SPF: pass client-ip=116.202.254.214; envelope-from=ged-emacs-devel@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.249, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Tue, 19 Sep 2023 08:13:28 -0400 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:310751 Archived-At: Eli Zaretskii wrote: > We don't need to discuss all this because solutions for > thread synchronization exist for a long time. We even use > quite a few of them already: the Lisp threads we have in > Emacs now provide some of these synchronization primitives, > which are built on top of existing capabilities built into > the OS and existing thread libraries. > > So the problem is not how to lock and serialize access to > a variable in general, the problem is how to do this in > Emacs so that we won't need to lock everything. Okay, excellent, but then why isn't it enough to just maintain a register of global variables and threads? If a thread wants to use it, look in the register, is it available? If not, get in line. And when it becomes available, pop a thread in the line, if there is one, and start over? Why do we have to lock everything just because we lock a single variable? -- underground experts united https://dataswamp.org/~incal