From owner-freebsd-hackers@FreeBSD.ORG Thu Nov 15 23:38:07 2012 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 6435D5BC; Thu, 15 Nov 2012 23:38:07 +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 37F7C8FC13; Thu, 15 Nov 2012 23:38:06 +0000 (UTC) Received: by mail-lb0-f182.google.com with SMTP id gg13so2182799lbb.13 for ; Thu, 15 Nov 2012 15:38:05 -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=59fXcjSOGzjdxybEZJU5FyWyLXXjWnlX2A1ncV1wX3E=; b=uIBJqE7kZ+G5C/FIwnacIyHHnd6O17lx9oiOLjUpWEDFK55aOHEc6jSO9973QS0/hr qN3vDWMqe7NysB2fx5gdC/3DoIEpGiIYMO2bjoUK2XPSww0pc3HFFpyJ6nDWIpOWhiEN 7ZlVfdVsD8YKuwKokCOaxXo8UsKCS90i9fHsobmpuIvqcSTvxTtp3H8CcW3UF4DTbDUW NEjvaFRDq4akIRfrL+EwOlTKxbZW9cq2QrSxKQzfgEP7/ivTQtUipsUeZmWoLiEK9nY9 Ed2YX2vUXwE/DMGY1OwRWTTOB3RjpXjMU+zW4jRl7vQERkq7DN1WOx2J4SHwMldXP7kd 4oxQ== MIME-Version: 1.0 Received: by 10.112.36.200 with SMTP id s8mr1267148lbj.92.1353022684920; Thu, 15 Nov 2012 15:38:04 -0800 (PST) Sender: asmrookie@gmail.com Received: by 10.112.134.5 with HTTP; Thu, 15 Nov 2012 15:38:04 -0800 (PST) In-Reply-To: <50A555BD.1010105@FreeBSD.org> References: <1353001175.1217.153.camel@revolution.hippie.lan> <1353009310.1217.172.camel@revolution.hippie.lan> <50A555BD.1010105@FreeBSD.org> Date: Thu, 15 Nov 2012 23:38:04 +0000 X-Google-Sender-Auth: O7HR17qiUsPNiPQPPnHwqI3xmLk 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-hackers@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list Reply-To: attilio@FreeBSD.org List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 15 Nov 2012 23:38:07 -0000 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. Attilio -- Peace can only be achieved by understanding - A. Einstein