From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sam Ravnborg Subject: Re: [PATCH 2/2] move unneeded data to initdata section Date: Thu, 15 Nov 2007 16:14:29 +0100 Message-ID: <20071115151429.GC22825@uranus.ravnborg.org> References: <20071107120100.GA10185@iris.sw.ru> <473C5ABC.5090204@sw.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <473C5ABC.5090204@sw.ru> Sender: netdev-owner@vger.kernel.org To: "Denis V. Lunev" Cc: "Eric W. Biederman" , "Denis V. Lunev" , davem@davemloft.net, containers@lists.osdl.org, netdev@vger.kernel.org, clg@fr.ibm.com, benjamin.thery@bull.net List-Id: containers.vger.kernel.org On Thu, Nov 15, 2007 at 05:42:04PM +0300, Denis V. Lunev wrote: > Eric W. Biederman wrote: > > "Denis V. Lunev" writes: > > > >> This patch reverts Eric's commit 2b008b0a8e96b726c603c5e1a5a7a509b5f61e35 > >> > >> It diets .text & .data section of the kernel if CONFIG_NET_NS is not set. > >> This is safe after list operations cleanup. > > > > Ok. This patch is technically safe because none of the touched > > code can live in a module and so we never touch the exit code path. > > > > However in the general case and as a code idiom this __net_initdata > > on struct pernet_operations is fundamentally horribly broken. > > > > Look at what happens if we use this idiom in module. There > > is only one definition of __initdata ".init.data". The module > > loader places all sections that begin with .init in a region of > > memory that will be discarded after module initialization. > > nothing is discarded after module load. Though, I can be wrong. Could > you point me to the exact place? If __initdata is not discarded after module load then we should do it. There is no reason to waste __initdata RAM when the module is loaded. Sam