* Sam Ravnborg <sam at ravnborg.org> wrote: > 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? Yes, the help text is wrong. Ingo
