From owner-freebsd-arch@FreeBSD.ORG Fri Nov 16 12:34:52 2012 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 08817902; Fri, 16 Nov 2012 12:34:52 +0000 (UTC) (envelope-from asmrookie@gmail.com) Received: from mail-lb0-f182.google.com (mail-lb0-f182.google.com [209.85.217.182]) by mx1.freebsd.org (Postfix) with ESMTP id 16BD28FC13; Fri, 16 Nov 2012 12:34:49 +0000 (UTC) Received: by mail-lb0-f182.google.com with SMTP id gg13so2648482lbb.13 for ; Fri, 16 Nov 2012 04:34:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:reply-to:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; bh=h1VKn6jICIer4+luGNM9zcnP28FEZvV9ZvIyCumJXYk=; b=ZGONhXRn+YAOh6j3pMTFoerFG5ky186UaeeodpSdx4XU+7GltscoNT54SNxM/15LLL 2SV/JYPod6xtZ/XflHs3SUluy8d0dYyUCivMvtHkCKWHhqTXHffR/qaycZnU4G3q+4zo yMIkBxsrRR9Fr4dmzrpOlU04aaQIpXSpZlMrPF/zdMrG7R56hCpLoOSbFS+keeeMiyOS +LbLoDOBgrYDfOWHqYnf0yAZPtK/giVcXKpRn5P6OdEo1tiSJSiYL6Qd9ionNj+FtOXc tnUpmg+JtbUNhQxppCyqQDmBa8wQ0tW2X7QA3x8zK1GYkqJcMxudq0wy1CuHgnYpxTij euuA== MIME-Version: 1.0 Received: by 10.152.110.234 with SMTP id id10mr4158218lab.15.1353069288423; Fri, 16 Nov 2012 04:34:48 -0800 (PST) Sender: asmrookie@gmail.com Received: by 10.112.134.5 with HTTP; Fri, 16 Nov 2012 04:34:48 -0800 (PST) In-Reply-To: <50A5E904.9040808@FreeBSD.org> References: <1353001175.1217.153.camel@revolution.hippie.lan> <1353009310.1217.172.camel@revolution.hippie.lan> <50A555BD.1010105@FreeBSD.org> <50A5E904.9040808@FreeBSD.org> Date: Fri, 16 Nov 2012 12:34:48 +0000 X-Google-Sender-Auth: rUcjWfXHcYOS78nbvmgr34faToI Message-ID: Subject: Re: [RFQ] make witness panic an option From: Attilio Rao To: Andriy Gapon Content-Type: text/plain; charset=UTF-8 Cc: Ian Lepore , Adrian Chadd , freebsd-arch@freebsd.org, freebsd-hackers@freebsd.org X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list Reply-To: attilio@FreeBSD.org List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 16 Nov 2012 12:34:52 -0000 On Fri, Nov 16, 2012 at 7:19 AM, Andriy Gapon wrote: > on 16/11/2012 01:38 Attilio Rao said the following: >> On Thu, Nov 15, 2012 at 8:51 PM, Andriy Gapon wrote: >>> on 15/11/2012 22:00 Adrian Chadd said the following: >>>> But I think my change is invaluable for development, where you want to >>>> improve and debug the locking and lock interactions of a subsystem. >>> >>> My practical experience was that if you mess up one lock in one place, then it >>> is a total mess further on. but apparently you've got a different practical >>> experience :) >>> What would indeed be invaluable to _me_ - if the LOR messages also produced the >>> stack(s) where a supposedly correct lock order was learned. >> >> Please note that the "supposedly correct lock order", as for the >> definition that it is correct, can be used in several different >> stacks. I don't see the point of saving it somewhere. >> The only helpful case would be if the "wrong order" is catched first. >> If this is really the case, I suggest you to force the order you >> expect in the static table so that the first time the wrong order >> happens it yells. > > Exactly my point - if I am a user of some code, not its developer, and I don't > know which one is the correct order I would have had the complete information > from the very start instead of having to jump through the hoops. I don't agree -- such informations are only useful to developers and also what should we do, store all the valid stacktraces? I don't understand what are you expecting here honestly. Attilio -- Peace can only be achieved by understanding - A. Einstein