From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: [PATCH 2/5] kbuild: allow archs to select build for link dead code/data elimination Date: Tue, 9 Aug 2016 17:37:42 -0700 Message-ID: <20160810003742.GI3078@tassilo.jf.intel.com> References: <1470399123-8455-1-git-send-email-npiggin@gmail.com> <1882847.dG563Vieov@wuerfel> <20160809031605.GF3078@tassilo.jf.intel.com> <3076474.M72Ro1h3RL@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <3076474.M72Ro1h3RL@wuerfel> Sender: linux-kbuild-owner@vger.kernel.org To: Arnd Bergmann Cc: Alan Modra , linuxppc-dev@lists.ozlabs.org, Nicholas Piggin , linux-arch@vger.kernel.org, Stephen Rothwell , Nicolas Pitre , linux-kbuild@vger.kernel.org List-Id: linux-arch.vger.kernel.org On Wed, Aug 10, 2016 at 12:29:29AM +0200, Arnd Bergmann wrote: > On Monday, August 8, 2016 8:16:05 PM CEST Andi Kleen wrote: > > > I don't understand what led Andi Kleen to also move .text.hot and > > > .text.unlikely together with .text [2], but this may have > > > been a related issue. > > > > > > [2] https://lkml.org/lkml/2015/7/19/377 > > > > The goal was just to move .hot and .unlikely all together, so that > > they are clustered and use the minimum amount of cache. On x86 doesn't > > matter where they are exactly, as long as each is together. > > If they are not explicitely listed then the linker interleaves > > them with the normal text, which defeats the purpose. > > I still don't see it, my reading of your patch is that you did > the opposite, by changing the description that puts all .text.hot > in front of .text, and all .text.unlikely after exit.text into > one that mixes them with .text. What am I missing here? No it doesn't mix .unlikely with .text, .unlikely is all in one place. -Andi -- ak@linux.intel.com -- Speaking for myself only From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga14.intel.com ([192.55.52.115]:5202 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932574AbcHJAht (ORCPT ); Tue, 9 Aug 2016 20:37:49 -0400 Date: Tue, 9 Aug 2016 17:37:42 -0700 From: Andi Kleen Subject: Re: [PATCH 2/5] kbuild: allow archs to select build for link dead code/data elimination Message-ID: <20160810003742.GI3078@tassilo.jf.intel.com> References: <1470399123-8455-1-git-send-email-npiggin@gmail.com> <1882847.dG563Vieov@wuerfel> <20160809031605.GF3078@tassilo.jf.intel.com> <3076474.M72Ro1h3RL@wuerfel> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3076474.M72Ro1h3RL@wuerfel> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Arnd Bergmann Cc: Alan Modra , linuxppc-dev@lists.ozlabs.org, Nicholas Piggin , linux-arch@vger.kernel.org, Stephen Rothwell , Nicolas Pitre , linux-kbuild@vger.kernel.org Message-ID: <20160810003742.7-XdMjdLlDzJ7lMqCnoNeW_ceEDFW3KMpg4Lh7W_BnE@z> On Wed, Aug 10, 2016 at 12:29:29AM +0200, Arnd Bergmann wrote: > On Monday, August 8, 2016 8:16:05 PM CEST Andi Kleen wrote: > > > I don't understand what led Andi Kleen to also move .text.hot and > > > .text.unlikely together with .text [2], but this may have > > > been a related issue. > > > > > > [2] https://lkml.org/lkml/2015/7/19/377 > > > > The goal was just to move .hot and .unlikely all together, so that > > they are clustered and use the minimum amount of cache. On x86 doesn't > > matter where they are exactly, as long as each is together. > > If they are not explicitely listed then the linker interleaves > > them with the normal text, which defeats the purpose. > > I still don't see it, my reading of your patch is that you did > the opposite, by changing the description that puts all .text.hot > in front of .text, and all .text.unlikely after exit.text into > one that mixes them with .text. What am I missing here? No it doesn't mix .unlikely with .text, .unlikely is all in one place. -Andi -- ak@linux.intel.com -- Speaking for myself only