[PATCH] Reintroduce NODES_SPAN_OTHER_NODES for powerpc

Reintroduce NODES_SPAN_OTHER_NODES for powerpc

Revert "[PATCH] Remove SPAN_OTHER_NODES config definition"
    This reverts commit f62859bb6871c5e4a8e591c60befc8caaf54db8c.
Revert "[PATCH] mm: remove arch independent NODES_SPAN_OTHER_NODES"
    This reverts commit a94b3ab7eab4edcc9b2cb474b188f774c331adf7.

Also update the comments to indicate that this is still required
and where its used.

Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Kravetz <kravetz@us.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Will Schmidt <will_schmidt@vnet.ibm.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 10 insertions, 0 deletions

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 8b6910465578..2bd9b7fb0f6c 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -751,6 +751,15 @@ config ARCH_MEMORY_PROBE
         def_bool y
         depends on MEMORY_HOTPLUG
 
+# Some NUMA nodes have memory ranges that span
+# other nodes.  Even though a pfn is valid and
+# between a node's start and end pfns, it may not
+# reside on that node.  See memmap_init_zone()
+# for details.
+config NODES_SPAN_OTHER_NODES
+        def_bool y
+        depends on NEED_MULTIPLE_NODES
+
 config PPC_64K_PAGES
         bool "64k page size"
         depends on PPC64
diff --git a/arch/powerpc/configs/pseries_defconfig b/arch/powerpc/configs/pseries_defconfig
index 9828663652e9..d2833c1a1f3d 100644
--- a/arch/powerpc/configs/pseries_defconfig
+++ b/arch/powerpc/configs/pseries_defconfig
@@ -184,6 +184,7 @@ CONFIG_SPLIT_PTLOCK_CPUS=4
 CONFIG_MIGRATION=y
 CONFIG_RESOURCES_64BIT=y
 CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID=y
+CONFIG_NODES_SPAN_OTHER_NODES=y
 # CONFIG_PPC_64K_PAGES is not set
 CONFIG_SCHED_SMT=y
 CONFIG_PROC_DEVICETREE=y