On Thu, May 07, 2009 at 03:26:51PM -0700, H. Peter Anvin wrote: > From: H. Peter Anvin <hpa at zytor.com> > > 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 <hpa at zytor.com> > --- > 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
