PPC32 memory models

PPC32 memory models

[Andy Whitcroft]

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It seems that there is some confusion over what we should be supporting
memory model wise for PPC32 under powerpc architecture.  The current
Kconfig limits you to only SPARSEMEM which isn't parameterised for PPC32
at all.  Are we expecting to be able to support PPC32 as yet in this
architecture?  If so it seems we have a couple of issues with the Kconfig.

Attached is a patch to enable FLATMEM and disable SPARSEMEM for PPC32
which seems to be the working combinations.  It may well not be what is
intended.  But I offer it to start discussions.

Comments.

-apw

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powerpc: ppc32 clean up available memory models

Clean up the currently available memory models for ppc32.  It seems
that we do need FLATMEM for ppc32 on non-NUMA.  It also seems that
SPARSEMEM is not parameterised yet so disable that.

Signed-off-by: Andy Whitcroft <apw@shadwen.org>
---
diff -upN reference/arch/powerpc/Kconfig current/arch/powerpc/Kconfig
--- reference/arch/powerpc/Kconfig
+++ current/arch/powerpc/Kconfig
@@ -584,14 +584,15 @@ config ARCH_SELECT_MEMORY_MODEL
 
 config ARCH_FLATMEM_ENABLE
        def_bool y
-       depends on PPC64 && !NUMA
+       depends on !NUMA
 
 config ARCH_SPARSEMEM_ENABLE
 	def_bool y
+	depends on PPC64
 
 config ARCH_SPARSEMEM_DEFAULT
 	def_bool y
-	depends on SMP && PPC_PSERIES
+	depends on SMP && PPC_PSERIES && NUMA
 
 source "mm/Kconfig"
 

Re: PPC32 memory models

[Paul Mackerras]

Andy Whitcroft writes:

> Attached is a patch to enable FLATMEM and disable SPARSEMEM for PPC32
> which seems to be the working combinations.  It may well not be what is
> intended.  But I offer it to start discussions.

Sounds right.

>  config ARCH_SPARSEMEM_DEFAULT
>  	def_bool y
> -	depends on SMP && PPC_PSERIES
> +	depends on SMP && PPC_PSERIES && NUMA

Shouldn't this depend on ARCH_SPARSEMEM_ENABLE?

Paul.

[PATCH] powerpc ppc32 clean up available memory models

[Andy Whitcroft]

Ok, attempt #2 at cleaning up the memory models for powerpc/ppc32.
Made it very explicit which combinations require FLATMEM and left
the defaults alone for SPARSEMEM.  Seems to do what I expect.

Comments.

-apw

=== 8< ===
powerpc: ppc32 clean up available memory models

Clean up the currently available memory models for ppc32 under
the powerpc architecture.  We need FLATMEM for ppc32 enable it.
SPARSEMEM is not parameterised for ppc32 so disable that.  Take this
opportunity to clean up white space for FLATMEM_ENABLE.

Against 2.6.15-rc3 with Anton's flatmem disable patch.

Signed-off-by: Andy Whitcroft <apw@shadowen.org>
---
diff -upN reference/arch/powerpc/Kconfig current/arch/powerpc/Kconfig
--- reference/arch/powerpc/Kconfig
+++ current/arch/powerpc/Kconfig
@@ -578,11 +578,12 @@ config ARCH_SELECT_MEMORY_MODEL
 	depends on PPC64
 
 config ARCH_FLATMEM_ENABLE
-       def_bool y
-       depends on PPC64 && !NUMA
+	def_bool y
+	depends on (PPC64 && !NUMA) || PPC32
 
 config ARCH_SPARSEMEM_ENABLE
 	def_bool y
+	depends on PPC64
 
 config ARCH_SPARSEMEM_DEFAULT
 	def_bool y