[PATCH 1/2] zone allow unaligned zone boundaries add configuration

[Andy Whitcroft <apw@shadowen.org>]

zone allow unaligned zone boundaries add configuration

Add a configuration definition for UNALIGNED_ZONE_BOUNDARIES.  Default
to on unless the architecture indicates that it ensures that the boundaries
are correctly aligned.

Signed-off-by: Andy Whitcroft <apw@shadowen.org>
---
 Kconfig |   13 +++++++++++++
 1 files changed, 13 insertions(+)
diff -upN reference/mm/Kconfig current/mm/Kconfig
--- reference/mm/Kconfig
+++ current/mm/Kconfig
@@ -145,3 +145,16 @@ config MIGRATION
 	  while the virtual addresses are not changed. This is useful for
 	  example on NUMA systems to put pages nearer to the processors accessing
 	  the page.
+
+#
+# Support for buddy zone boundaries within a MAX_ORDER sized area.
+#
+config UNALIGNED_ZONE_BOUNDARIES
+	bool "Unaligned zone boundaries"
+	default n if ARCH_ALIGNED_ZONE_BOUNDARIES
+	default y
+	help
+	  Adds checks to the buddy allocator to ensure we do not
+	  coalesce buddies across zone boundaries.  The default
+	  should be correct for your architecture.  Enable this if
+	  you are having trouble and you are requested to in dmesg.

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