From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay1.corp.sgi.com [137.38.102.111]) by oss.sgi.com (Postfix) with ESMTP id D2C0729DFA for ; Wed, 24 Apr 2013 17:58:42 -0500 (CDT) Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by relay1.corp.sgi.com (Postfix) with ESMTP id B09FB8F8033 for ; Wed, 24 Apr 2013 15:58:39 -0700 (PDT) Received: from ipmail06.adl6.internode.on.net (ipmail06.adl6.internode.on.net [150.101.137.145]) by cuda.sgi.com with ESMTP id qXmGOoEleIBuPdvj for ; Wed, 24 Apr 2013 15:58:38 -0700 (PDT) Date: Thu, 25 Apr 2013 08:58:21 +1000 From: Dave Chinner Subject: Re: [PATCH V2] xfs: introduce CONFIG_XFS_WARN Message-ID: <20130424225821.GV10481@dastard> References: <1366699138-24055-1-git-send-email-david@fromorbit.com> <5176833C.8070305@redhat.com> <20130423210226.GN10481@dastard> <20130424085546.GQ10481@dastard> <1366828792.3762.32405.camel@chandra-dt.ibm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1366828792.3762.32405.camel@chandra-dt.ibm.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Chandra Seetharaman Cc: Brian Foster , xfs@oss.sgi.com On Wed, Apr 24, 2013 at 01:39:52PM -0500, Chandra Seetharaman wrote: > Hi Dave, > > Since this solution is for production environment, would it be valuable > to have a sysctl variable to allow enabling/disabling XFS_WARN, as > opposed to needing to recompile the module afresh ? The idea is that distros enable it on the debug kernel packages rather than using CONFIG_XFS_DEBUG=y. Hence if someone has a problem, they just install the debug kernel and they get all this additional checking. There are roughly 1700 ASSERT statements in the XFS code, so compiling them in unconditionally is a lot of extra code. Adding a sysctl to make them conditional adds as many branches into the code than in 99.99999% of calls are never going to evaluate as true. The convenience of a sysctl is more than outweighed by the additional overhead for the majortiy of people that don't need to diagnose problems on their system. Hence I don't think the overhead of unconditionally compiling in ASSERT checks is worth while for the majority of users, especially as most distros ship a debug kernel for exactly this purpose.... Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs