From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751780AbaHGTD0 (ORCPT ); Thu, 7 Aug 2014 15:03:26 -0400 Received: from relay3-d.mail.gandi.net ([217.70.183.195]:51402 "EHLO relay3-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751159AbaHGTDY (ORCPT ); Thu, 7 Aug 2014 15:03:24 -0400 X-Originating-IP: 173.246.103.110 Date: Thu, 7 Aug 2014 12:02:44 -0700 From: Josh Triplett To: Sam Ravnborg Cc: akpm@linux-foundation.org, torvalds@linux-foundation.org, David Rientjes , "Luis R. Rodriguez" , "H. Peter Anvin" , Ingo Molnar , Thomas Gleixner , x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] x86: Add "make tinyconfig" to configure the tiniest possible kernel Message-ID: <20140807190243.GA5580@jtriplet-mobl1> References: <20140806222419.GA2566@jtriplet-mobl1> <20140806223152.GA14348@jtriplet-mobl1> <20140807160352.GB1382@ravnborg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140807160352.GB1382@ravnborg.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 07, 2014 at 06:03:52PM +0200, Sam Ravnborg wrote: > On Wed, Aug 06, 2014 at 03:31:54PM -0700, Josh Triplett wrote: > > Since commit 5d2acfc7b974bbd3858b4dd3f2cdc6362dd8843a ("kconfig: make > > allnoconfig disable options behind EMBEDDED and EXPERT") in 3.15-rc1, > > "make allnoconfig" disables every possible config option. > > > > However, a few configuration options (CC_OPTIMIZE_FOR_SIZE, > > OPTIMIZE_INLINING) produce a smaller kernel when turned on, and a few > > choices exist (compression, highmem, allocator) for which a non-default > > option produces a smaller kernel. > > > > Add a "tinyconfig" option, which starts from allnoconfig and then sets > > these options to configure the tiniest possible kernel. This provides a > > better baseline for embedded systems or efforts to reduce kernel size. > > In general I dislike the whole approach where we introduce makefile > magic to support diverse config snippets. > Another approch where we factor out this from the MAkefile seems much leaner. > > And for this specific patch then this is not x86 specific at all. > If we keep the logic in the makefiles than we should: > 1) Make the infrastructure general > 2) Document it > 3) Find another home for the config snippets that are non-arch specific like this one I'll refactor this and resubmit. > > diff --git a/arch/x86/configs/tiny.config b/arch/x86/configs/tiny.config > > new file mode 100644 > > index 0000000..8f0e54c > > --- /dev/null > > +++ b/arch/x86/configs/tiny.config > > @@ -0,0 +1,5 @@ > > +CONFIG_CC_OPTIMIZE_FOR_SIZE=y > > +CONFIG_KERNEL_XZ=y > > +CONFIG_NOHIGHMEM=y > > +CONFIG_OPTIMIZE_INLINING=y > > +CONFIG_SLOB=y > All the above are general options that apply equal to arm than to x86. NOHIGHMEM isn't. - Josh Triplett