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: Concurrency via isolated process/thread Date: Thu, 06 Jul 2023 18:10:47 +0300 Message-ID: <83sfa1gjns.fsf@gnu.org> References: <871qhnr4ty.fsf@localhost> <87v8ezpov0.fsf@localhost> <83r0pnk2az.fsf@gnu.org> <87pm57pns8.fsf@localhost> <87lefvp55t.fsf@yahoo.com> <87sfa28ura.fsf@localhost> <87cz16o8vz.fsf@yahoo.com> <87jzve8r4m.fsf@localhost> <871qhmo5nv.fsf@yahoo.com> <87bkgq8p5t.fsf@localhost> <831qhmjwk0.fsf@gnu.org> <875y6y8nlr.fsf@localhost> <87h6qhnalc.fsf@yahoo.com> <87ilax71wo.fsf@localhost> <878rbtkz2c.fsf@yahoo.com> <87a5w96x2o.fsf@localhost> <87jzvdjjp4.fsf@yahoo.com> <877crd6w53.fsf@localhost> <877crdjiwn.fsf@yahoo.com> <874jmh6v4s.fsf@localhost> <83y1jtgmbw.fsf@gnu.org> <87zg49xfke.fsf@localhost> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="40739"; mail-complaints-to="usenet@ciao.gmane.io" Cc: luangruo@yahoo.com, emacs-devel@gnu.org To: Ihor Radchenko Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Thu Jul 06 17:11:15 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 1qHQdV-000AQc-Mc for ged-emacs-devel@m.gmane-mx.org; Thu, 06 Jul 2023 17:11:13 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qHQd6-0007jN-Tv; Thu, 06 Jul 2023 11:10:48 -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 1qHQd5-0007j3-I5 for emacs-devel@gnu.org; Thu, 06 Jul 2023 11:10:47 -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 1qHQd5-00029o-7V; Thu, 06 Jul 2023 11:10:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=References:Subject:In-Reply-To:To:From:Date: mime-version; bh=wChD8ZEqEs/wyIxXOzIxsxqnlCcHK2WEHkPzGXiRJsI=; b=VcI06tOeLNuU MZLPQ7BNey3QAVuKL+/50swlAmwM0mudRU4yr7mfplDDpDbcNHB2JcmFZU9rUax4Et7SLcslYwmVU ctwMwwZndFsLUFl/eECZJUb7M/MtU8jqN4gE2MLdUq4aQKDB+aC0eTdg1cjqlcFoN6UfWS1rZ2ZDF Dt71OW8GHQrzum5JCAvBMzOGUSxFlH3gaugTUipicZZa3jGZ/JnfYN0HO7ENU9t4f5ZWSmpUmdF7O VrV/z4UO2lr2cHP5cOK6CesO5o/0tFYoz2oGfnQh4t44qqj82umWxPzLOBMLS/MnWFCTJk3OfKv36 jeUp8KnnX1lOb7+O7fvIBQ==; Original-Received: from [87.69.77.57] (helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qHQd4-0003IG-Nq; Thu, 06 Jul 2023 11:10:47 -0400 In-Reply-To: <87zg49xfke.fsf@localhost> (message from Ihor Radchenko on Thu, 06 Jul 2023 14:47:13 +0000) 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:307513 Archived-At: > From: Ihor Radchenko > Cc: luangruo@yahoo.com, emacs-devel@gnu.org > Date: Thu, 06 Jul 2023 14:47:13 +0000 > > Eli Zaretskii writes: > > >> My understanding is > >> > >> CHECK_STRING (XCAR (foo)); > >> > >> foo = XSTRING (XCAR (foo)); > >> > >> So, locking is needed to ensure that CHECK_STRING assertion remains valid. > >> > >> Or did you refer to something else? > > > > I don't know what Po Lu had in mind, but one aspect of this is that a > > string object might keep its memory address, but its data could be > > relocated. This can happen as part of GC, and is the reason why > > string data is kept separate from the string itself. > > This does not change my understanding. > Locking should prevent manipulations with object data over the time span > the code expects the object to be unchanged. That could defeat GC, should Emacs decide to run it while the lock is in place.