From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Subject: Re: [RESEND PATCH] fs/super.c set_anon_super calling optimization Date: Fri, 30 Nov 2012 04:05:56 +0000 Message-ID: <20121130040556.GD4939@ZenIV.linux.org.uk> References: <508924AB.4060902@gmail.com> <20121026131441.GA22256@andromeda.usersys.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: Abhijit Pawar , linux-fsdevel@vger.kernel.org, "linux-btrfs@vger.kernel.org" , linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org Return-path: Content-Disposition: inline In-Reply-To: <20121026131441.GA22256@andromeda.usersys.redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Fri, Oct 26, 2012 at 11:14:41AM -0200, Carlos Maiolino wrote: > Hi, > > On Thu, Oct 25, 2012 at 05:08:19PM +0530, Abhijit Pawar wrote: > > Hi, > > set_anon_super is called by many filesystems. Some call directly and > > some call through the wrapper. Many of them in the wrapper's call to > > this function are passing the second argument to this function which > > is not used anywhere. > > > > This patch replaces the second variable with NULL. > > > > If the variable isn't used anymore, why don't just get rid of it, instead of > call the function passing a NULL pointer on it? Because we want it to be a valid sget() callback. I doubt that this optimization is worth doing, though - might even micro-pessimize the things on architectures where all arguments are passed in registers.