From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id B47A38D0039 for ; Thu, 27 Jan 2011 03:23:30 -0500 (EST) Date: Thu, 27 Jan 2011 09:23:20 +0100 From: Michal Hocko Subject: Re: [PATCH] memsw: handle swapaccount kernel parameter correctly Message-ID: <20110127082320.GA15500@tiehlicka.suse.cz> References: <20110126152158.GA4144@tiehlicka.suse.cz> <20110126140618.8e09cd23.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110126140618.8e09cd23.akpm@linux-foundation.org> Sender: owner-linux-mm@kvack.org To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, balbir@linux.vnet.ibm.com, KAMEZAWA Hiroyuki , Daisuke Nishimura , stable@kernel.org List-ID: On Wed 26-01-11 14:06:18, Andrew Morton wrote: > On Wed, 26 Jan 2011 16:21:58 +0100 > Michal Hocko wrote: > > > I am sorry but the patch which added swapaccount parameter is not > > correct (we have discussed it https://lkml.org/lkml/2010/11/16/103). > > I didn't get the way how __setup parameters are handled correctly. > > The patch bellow fixes that. > > > > I am CCing stable as well because the patch got into .37 kernel. > > > > --- > > >From 144c2e8aed27d82d48217896ee1f58dbaa7f1f84 Mon Sep 17 00:00:00 2001 > > From: Michal Hocko > > Date: Wed, 26 Jan 2011 14:12:41 +0100 > > Subject: [PATCH] memsw: handle swapaccount kernel parameter correctly > > > > __setup based kernel command line parameters handled in > > obsolete_checksetup provides the parameter value including = (more > > precisely everything right after the parameter name) so we have to check > > for =0 resp. =1 here. If no value is given then we get an empty string > > rather then NULL. > > This doesn't provide a description of the bug which just got fixed. > > From reading the code I think the current behaviour is > > "swapaccount": works OK Not really because the original test was !s || s="1" but as I am writing in the commit message we are getting an empty string rather than NULL in no parameter value case.. So noswapaccount is actually the only thing that is working. > "noswapaccount": works OK > "swapaccount=0": doesn't do anything > "swapaccount=1": doesn't do anything > > but I might be wrong about that. Please send a changelog update to > clarify all this. Sorry for not being specific enough. What about somthing like this: ---