From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Ihor Radchenko Newsgroups: gmane.emacs.devel Subject: Re: Concurrency via isolated process/thread Date: Mon, 17 Jul 2023 09:54:31 +0000 Message-ID: <87o7kazwvc.fsf@localhost> References: <871qhnr4ty.fsf@localhost> <87zg48apwr.fsf@localhost> <83edljg8ub.fsf@gnu.org> <87o7knbxr7.fsf@localhost> <838rbrg4mg.fsf@gnu.org> <87ilavbvdr.fsf@localhost> <834jmffvhy.fsf@gnu.org> <878rbrbmwr.fsf@localhost> <83fs5zecpo.fsf@gnu.org> <87351zbi72.fsf@localhost> <83351yevde.fsf@gnu.org> <87cz12ad2w.fsf@localhost> <83a5w6cwdr.fsf@gnu.org> <87pm518m0g.fsf@localhost> <83o7kl9tyj.fsf@gnu.org> <874jmd89us.fsf@localhost> <87y1jf29a4.fsf@localhost> <878rbf0y6b.fsf@localhost> <87h6q36ijw.fsf@yahoo.com> <875y6i2a3n.fsf@localhost> <87cz0q7u71.fsf@yahoo.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="38057"; mail-complaints-to="usenet@ciao.gmane.io" Cc: Eli Zaretskii , emacs-devel@gnu.org To: Po Lu Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Mon Jul 17 11:55:23 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 1qLKwt-0009hm-8O for ged-emacs-devel@m.gmane-mx.org; Mon, 17 Jul 2023 11:55:23 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qLKvy-0004AU-Sf; Mon, 17 Jul 2023 05:54:26 -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 1qLKvw-0004AI-AS for emacs-devel@gnu.org; Mon, 17 Jul 2023 05:54:24 -0400 Original-Received: from mout01.posteo.de ([185.67.36.65]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qLKvu-0008FU-6v for emacs-devel@gnu.org; Mon, 17 Jul 2023 05:54:23 -0400 Original-Received: from submission (posteo.de [185.67.36.169]) by mout01.posteo.de (Postfix) with ESMTPS id D59A5240028 for ; Mon, 17 Jul 2023 11:54:19 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.net; s=2017; t=1689587659; bh=0iBFEK5bh/aLjGYrjHDbZCKalPU/KBUGu3efgXH+URA=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:From; b=KvylLgnHFcBvjCf3AKq3hIau62qwnQ2DxEWHo81QXNoPT9g4IU2YUPFQnf97aQjIf s1piMrDFhbJasBrmO1tNYSvFY7Gy5ly7TwdQaX8EDiwY4Vn1wfoBxUmGGmYmNOMnZv u7FFBcYzNqL8pwmnSVaVVIJM6OiT6NNomgK6S2U8Jm48yTOtV2DN0SdqJZ6YaXlai5 T4DFl7MgUOjHsk2wsezUMSVCuoyVQ0mQ86+J3EEil25ihnllrpz33Yu1l68jRH4JQ2 0cqoWqjM/Mqe7sQ4v9WGpYNP2TWatgksMYr8FUY+ef0NP+p802QOSzrSAHske4D85H UPQvpMRg61MZg== Original-Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4R4HVL6xQPz9rxD; Mon, 17 Jul 2023 11:54:18 +0200 (CEST) In-Reply-To: <87cz0q7u71.fsf@yahoo.com> Received-SPF: pass client-ip=185.67.36.65; envelope-from=yantar92@posteo.net; helo=mout01.posteo.de X-Spam_score_int: -53 X-Spam_score: -5.4 X-Spam_bar: ----- X-Spam_report: (-5.4 / 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, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H5=-1, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable 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:307922 Archived-At: Po Lu writes: >> And I am not sure how things will affect memory alignment of symbol >> objects (I do not fully understand the relevant comments in lisp.h) > > How is any of this relevant to symbol alignment? Please tell us which > comments you're referring to. GCALIGNED_UNION_MEMBER >> we should be careful about concurrent read access to struct slots in >> shared objects. > > Fortunately, there are very few direct references to fields within > Lisp_Symbol. What I mean is a situation when we try to read sym->u.s.val.value, but the value becomes Lisp_Object value[]. Then, realloc calls in other thread may create a race condition when accessing array element may point to obsolete memory address that was only valid prior to realloc. Of course, it is just a trivial example. I am worried about less obvious scenarios (those, I can't predict in advance). -- Ihor Radchenko // yantar92, Org mode contributor, Learn more about Org mode at . Support Org development at , or support my work at