From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757668AbZEHHeL (ORCPT ); Fri, 8 May 2009 03:34:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755386AbZEHHd4 (ORCPT ); Fri, 8 May 2009 03:33:56 -0400 Received: from pfepb.post.tele.dk ([195.41.46.236]:42136 "EHLO pfepb.post.tele.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753596AbZEHHd4 (ORCPT ); Fri, 8 May 2009 03:33:56 -0400 Date: Fri, 8 May 2009 09:36:06 +0200 From: Sam Ravnborg To: "H. Peter Anvin" Cc: linux-kernel@vger.kernel.org, vgoyal@redhat.com, hbabu@us.ibm.com, kexec@lists.infradead.org, ying.huang@intel.com, mingo@elte.hu, tglx@linutronix.de, ebiederm@xmission.com, "H. Peter Anvin" Subject: Re: [PATCH 03/14] x86, config: change defaults PHYSICAL_START and PHYSICAL_ALIGN Message-ID: <20090508073606.GC12808@uranus.ravnborg.org> References: <1241735222-6640-1-git-send-email-hpa@linux.intel.com> <1241735222-6640-4-git-send-email-hpa@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1241735222-6640-4-git-send-email-hpa@linux.intel.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 07, 2009 at 03:26:51PM -0700, H. Peter Anvin wrote: > From: H. Peter Anvin > > Change the default for CONFIG_PHYSICAL_START to 16 MB; 4 MB if > EMBEDDED. Change the default for CONFIG_PHYSICAL_ALIGN to match up > with a large page alignment datum (4 MB for non-PAE, 2 MB for PAE.) > > The default of 16 MB is designed to avoid occupying ZONE_DMA, as well > as avoiding a 15-16 MB memory hole, which some vendors inexplicably > still have in their systems. > > [ Impact: minor performance improvement, leave ZONE_DMA free ] > > Signed-off-by: H. Peter Anvin > --- > arch/x86/Kconfig | 19 +++++++++++-------- > 1 files changed, 11 insertions(+), 8 deletions(-) > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index 039c3f0..13b3a5a 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -1455,17 +1455,20 @@ config KEXEC_JUMP > > config PHYSICAL_START > hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP) > - default "0x1000000" if X86_NUMAQ > - default "0x200000" if X86_64 > - default "0x100000" > + default "0x400000" if EMBEDDED > + default "0x1000000" > ---help--- > This gives the physical address where the kernel is loaded. > > If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then > bzImage will decompress itself to above physical address and > - run from there. Otherwise, bzImage will run from the address where > - it has been loaded by the boot loader and will ignore above physical > - address. > + run from there. Otherwise, bzImage will run from the either > + the above physical address or where it has been loaded by > + the boot loader, whichever is higher. > + > + For embedded machines with very small memory (less than > + about 24 MB) this may need to be adjusted downward from the > + default value of 0x1000000 (16 MB). But in the above you say that default is "0x400000" if EMBEDDED That is in contradiction with the help - no? Sam