This gives DISCONTIGMEM a bit more help text to explain what it does, not just
when to choose it.
Signed-off-by: NDave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I got some feedback from users who think that the new "Memory Model" menu is a
little invasive.  This patch will hide that menu, except when
CONFIG_EXPERIMENTAL is enabled *or* when an individual architecture wants it.

An individual arch may want to enable it because they've removed their
arch-specific DISCONTIG prompt in favor of the mm/Kconfig one.
Signed-off-by: NDave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The following patch applies on top of 2.6.12-rc2-mm1.  It fixes a minor
user interaction issue, and an early reference to SPARSEMEM.

This "choice" menu would always default to FLATMEM, as it was listed first.
 Move it to the end so that the other defaults have a chance first.
Signed-off-by: NDave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

There is some confusion that arose when working on SPARSEMEM patch between
what is needed for DISCONTIG vs. NUMA.

Multiple pg_data_t's are needed for DISCONTIGMEM or NUMA, independently.
All of the current NUMA implementations require an implementation of
DISCONTIG.  Because of this, quite a lot of code which is really needed for
NUMA is actually under DISCONTIG #ifdefs.  For SPARSEMEM, we changed some
of these #ifdefs to CONFIG_NUMA, but that broke the DISCONTIG=y and NUMA=n
case.

Introducing this new NEED_MULTIPLE_NODES config option allows code that is
needed for both NUMA or DISCONTIG to be separated out from code that is
specific to DISCONTIG.

One great advantage of this approach is that it doesn't require every
architecture to be converted over.  All of the current implementations
should "just work", only the ones implementing SPARSEMEM will have to be
fixed up.

The change to free_area_init() makes it work inside, or out of the new
config option.
Signed-off-by: NDave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

With sparsemem being introduced, we need a central place for new
memory-related .config options: mm/Kconfig.  This allows us to remove many
of the duplicated arch-specific options.

The new option, CONFIG_FLATMEM, is there to enable us to detangle NUMA and
DISCONTIGMEM.  This is a requirement for sparsemem because sparsemem uses
the NUMA code without the presence of DISCONTIGMEM.  The sparsemem patches
use CONFIG_FLATMEM in generic code, so this patch is a requirement before
applying them.

Almost all places that used to do '#ifndef CONFIG_DISCONTIGMEM' should use
'#ifdef CONFIG_FLATMEM' instead.
Signed-off-by: NAndy Whitcroft <apw@shadowen.org>
Signed-off-by: NDave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>