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: MPS: Area scanners Date: Mon, 06 May 2024 21:24:36 +0300 Message-ID: <86fruubxy3.fsf@gnu.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="35796"; mail-complaints-to="usenet@ciao.gmane.io" Cc: eller.helmut@gmail.com, emacs-devel@gnu.org To: Gerd =?utf-8?Q?M=C3=B6llmann?= Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Mon May 06 20:25:56 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 1s432B-000943-FG for ged-emacs-devel@m.gmane-mx.org; Mon, 06 May 2024 20:25:55 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1s4318-0003BB-3j; Mon, 06 May 2024 14:24:50 -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 1s4316-00038m-E3 for emacs-devel@gnu.org; Mon, 06 May 2024 14:24:48 -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 1s4315-00049x-SE; Mon, 06 May 2024 14:24:48 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=MIME-version:References:Subject:In-Reply-To:To:From: Date; bh=fTDNVONhWZ2QKNBh/Bx/5u1Qy5VHCk21QFJ94suav9U=; b=lw4irB/fnVbsJTXskvXs DL0nF+JczjE4EysDHtHnbZLFzANsHHDZsWvirK+w0MtssAJlHRo11Z+CEXO/zW+qWVudRO7Bs/2vk 8zc4PqQwcc7ZJ1jFwOEA+hR9nAv/2ywtD1Tjcg41RzKBe4cj12cmG+BK2tdAkhrTa5AcLOuSrbRiy Tf0GLrt3VC0+zt5qHC7+uxlRmn26soRqjk+3LXPMAOqAsgb1Vqrx+A0dsk07k83FleLO71ILkivAY OrKuwhvUJr55uV3NOKivBa2RhqtDyf5uMsFsih+S1ykZuwSOn1mu9ll2c8WAhAwEoPS/ny0YiKh4Z Cq3WD1HRZZb7Fw==; In-Reply-To: (message from Gerd =?utf-8?Q?M=C3=B6llmann?= on Mon, 06 May 2024 19:12:08 +0200) 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:318907 Archived-At: > From: Gerd Möllmann > Cc: Emacs Devel > Date: Mon, 06 May 2024 19:12:08 +0200 > > I remember now why I thought tht scan_bc would work they way I thought, > so that I could compute a suitable scan end and so on. I read in the MPS > docs this: > > type mps_area_scan_t > > Warning: Area scanning functions are subject to the same set of > restrictions as format scanning functions, described under Cautions. > > And Cautions links to a long list containing > > 7.3. Cautions > > The MPS guarantees that format methods have exclusive access to the > object for the duration of the call. This guarantee may entail > suspending arbitrary threads. The methods that manipulate the object > must not perform any sort of inter-thread locking or communication. > > etc. > > Question is of course now, what is with the exclusive access for area > scanning functions? Is that point a member of the "set of restrictions"? > > I can't answer that ATM. Maybe someone else can? What are those scanning function you are talking about? are they all those fix_SOMETHING functions that run off dflt_scan etc.? If so, these scan Lisp objects, do they? And so, the above restrictions on inter-thread locking or communication are relevant for those fix_SOMETHING functions? If so, why is inter-thread locking relevant? I don't see anything like that in those fix_SOMETHING functions. Did I miss something?