Re: [RFC][PATCH 1/4] create mm/Kconfig for arch-independent memory options

["Randy.Dunlap" <rddunlap@osdl.org>]

Dave Hansen wrote:
> With sparsemem and memory hotplug there are quite a few options that
> we kept adding identically in several different architectures.  This
> new file allows some of these to be consolidated.
> 
> Signed-off-by: Andy Whitcroft <apw@shadowen.org>
> Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
> ---
> 
>  memhotplug-dave/mm/Kconfig |   41 +++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 41 insertions(+)
> 
> diff -puN mm/Kconfig~A6-mm-Kconfig mm/Kconfig
> --- memhotplug/mm/Kconfig~A6-mm-Kconfig	2005-03-25 08:08:22.000000000 -0800
> +++ memhotplug-dave/mm/Kconfig	2005-03-25 08:08:22.000000000 -0800
> @@ -0,0 +1,41 @@
> +choice
> +	prompt "Memory model"
> +	default FLATMEM
> +	default SPARSEMEM if ARCH_SPARSEMEM_DEFAULT
> +	default DISCONTIGMEM if ARCH_DISCONTIGMEM_DEFAULT
> +
> +config FLATMEM
> +	bool "Flat Memory"
> +	depends on !ARCH_DISCONTIGMEM_ENABLE || ARCH_FLATMEM_ENABLE
> +	help
> +	  This option allows you to change some of the ways that
> +	  Linux manages its memory internally.  Most users will
> +	  only have one option here: FLATMEM.  This is normal
> +	  and a correct option.
> +
> +	  Some users of more advanced features like NUMA and
> +	  memory hotplug may have different options here.
> +	  DISCONTIGMEM is an more mature, better tested system,
> +	  but is incompatible with memory hotplug and may suffer
> +	  decreased performance over SPARSEMEM.  If unsure between
> +	  "Sparse Memory" and "Discontiguous Memory", choose
Where is the "Sparse Memory" option?  I didn't find it.

> +	  "Discontiguous Memory".
> +
> +	  If unsure, choose FLATMEM.
> +
> +config DISCONTIGMEM
> +	bool "Discontigious Memory"
> +	depends on ARCH_DISCONTIGMEM_ENABLE
> +	help
> +	  If unsure, choose this option over "Sparse Memory".
Same question....

> +endchoice
> +
> +#
> +# Both the NUMA code and DISCONTIGMEM use arrays of pg_data_t's
> +# to represent different areas of memory.  This variable allows
> +# those dependencies to exist individually.
> +#
> +config NEED_MULTIPLE_NODES
> +	def_bool y
> +	depends on DISCONTIGMEM || NUMA


-- 
~Randy