Re: [PATCH] x86: make generic arch support NUMAQ v2

[Sam Ravnborg <sam@ravnborg.org>]

On Thu, Jun 05, 2008 at 05:54:40PM -0700, Yinghai Lu wrote:
> On Thu, Jun 5, 2008 at 5:14 PM, Yinghai Lu <yhlu.kernel@gmail.com> wrote:
> >
> > so it could fallback to normal numa.
> >
> > NUMAQ depends on GENERICARCH
> >
> > also decouple genericarch numa with acpi.
> >
> > Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
> >
> > Index: linux-2.6/arch/x86/Kconfig
> > ===================================================================
> > --- linux-2.6.orig/arch/x86/Kconfig
> > +++ linux-2.6/arch/x86/Kconfig
> > @@ -264,17 +264,6 @@ config X86_VOYAGER
> >          If you do not specifically know you have a Voyager based machine,
> >          say N here, otherwise the kernel you build will not be bootable.
> >
> > -config X86_NUMAQ
> > -       bool "NUMAQ (IBM/Sequent)"
> > -       depends on SMP && X86_32 && PCI
> > -       select NUMA
> > -       help
> > -         This option is used for getting Linux to run on a (IBM/Sequent) NUMA
> > -         multiquad box. This changes the way that processors are bootstrapped,
> > -         and uses Clustered Logical APIC addressing mode instead of Flat Logical.
> > -         You will need a new lynxer.elf file to flash your firmware with - send
> > -         email to <Martin.Bligh@us.ibm.com>.
> > -
> >  config X86_SUMMIT
> >        bool "Summit/EXA (IBM x440)"
> >        depends on X86_32 && SMP
> > @@ -307,12 +296,12 @@ config X86_VISWS
> >          and vice versa. See <file:Documentation/sgi-visws.txt> for details.
> >
> >  config X86_GENERICARCH
> > -       bool "Generic architecture (Summit, bigsmp, ES7000, default)"
> > +       bool "Generic architecture (NUMAQ, Summit, bigsmp, ES7000, default)"
> >        depends on X86_32
> >        help
> > -          This option compiles in the Summit, bigsmp, ES7000, default subarchitectures.
> > -         It is intended for a generic binary kernel.
> > -         If you want a NUMA kernel, select ACPI.   We need SRAT for NUMA.
> > +          This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
> > +         subarchitectures.  It is intended for a generic binary kernel.
> > +         You need enable NUMA, otherwise NUMAQ is skipped.
> >
> >  config X86_ES7000
> >        bool "Support for Unisys ES7000 IA32 series"
> > @@ -348,6 +337,17 @@ config X86_VSMP
> >
> >  endchoice
> >
> > +config X86_NUMAQ
> > +       bool "NUMAQ (IBM/Sequent)"
> > +       depends on SMP && X86_32 && PCI && X86_GENERICARCH
> > +       select NUMA
> > +       help
> > +         This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
> > +         NUMA multiquad box. This changes the way that processors are
> > +         bootstrapped, and uses Clustered Logical APIC addressing mode instead
> > +         of Flat Logical.  You will need a new lynxer.elf file to flash your
> > +         firmware with - send email to <Martin.Bligh@us.ibm.com>.
> > +
> >  config SCHED_NO_NO_OMIT_FRAME_POINTER
> >        def_bool y
> >        prompt "Single-depth WCHAN output"
> > @@ -908,9 +908,9 @@ config X86_PAE
> >  config NUMA
> >        bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
> >        depends on SMP
> > -       depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || (X86_SUMMIT || X86_GENERICARCH) && ACPI) && EXPERIMENTAL)
> > +       depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_GENERICARCH || X86_SUMMIT && ACPI) && EXPERIMENTAL)
> >        default n if X86_PC
> > -       default y if (X86_NUMAQ || X86_SUMMIT)
> > +       default y if (X86_NUMAQ || X86_SUMMIT || X86_GENERICARCH)
> >        help
> >          Enable NUMA (Non Uniform Memory Access) support.
> >          The kernel will try to allocate memory used by a CPU on the
> 
> Sam,
> 
> now NUMAQ depends on GENERICARCH.
> 
> and Ingo want to make oldconfig to migration NUMAQ....to select GENERICARCH...
> 
> but if i add select X86_GENERICARCH, make oldconfig will get

It is my understanding that special support for NUMAQ should die,
so the only remaning usage of CONFIG_NUMAQ is if set to select GENERICARCH.
In other words that you should not use CONFIG_NUMAQ anywhere in the code
but solely rely on GENERICARCH and then do runtime detection of the
other things.

That has been my understanding of the discussions about eliminating the
subarch support - but obviosuly Ingo & Co are the ones with better
knowledge in this area.
My point is that NUMAQ should not be a visible option at all in
*config and solely be present to select GENERICARCH is set to Y
in a defconfig file.
So you would have something like:

config NUMAQ
	defbool n

config GENERICARCH
	default NUMAQ

I am though not sure if this works as expected when NUMAQ is not visible
but it should be trivial to test.

	Sam