Merge ../torvalds-2.6/

[pandora-kernel.git] / mm / Kconfig

diff --git a/mm/Kconfig b/mm/Kconfig
index 5127441..4e9937a 100644 (file)
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -6,6 +6,7 @@ choice
        prompt "Memory model"
        depends on SELECT_MEMORY_MODEL
        default DISCONTIGMEM_MANUAL if ARCH_DISCONTIGMEM_DEFAULT
+       default SPARSEMEM_MANUAL if ARCH_SPARSEMEM_DEFAULT
        default FLATMEM_MANUAL
 
 config FLATMEM_MANUAL
@@ -17,7 +18,15 @@ config FLATMEM_MANUAL
          only have one option here: FLATMEM.  This is normal
          and a correct option.
 
-         If unsure, choose this option over any other.
+         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
+         "Discontiguous Memory".
+
+         If unsure, choose this option (Flat Memory) over any other.
 
 config DISCONTIGMEM_MANUAL
        bool "Discontigious Memory"
@@ -35,15 +44,38 @@ config DISCONTIGMEM_MANUAL
 
          If unsure, choose "Flat Memory" over this option.
 
+config SPARSEMEM_MANUAL
+       bool "Sparse Memory"
+       depends on ARCH_SPARSEMEM_ENABLE
+       help
+         This will be the only option for some systems, including
+         memory hotplug systems.  This is normal.
+
+         For many other systems, this will be an alternative to
+         "Discontigious Memory".  This option provides some potential
+         performance benefits, along with decreased code complexity,
+         but it is newer, and more experimental.
+
+         If unsure, choose "Discontiguous Memory" or "Flat Memory"
+         over this option.
+
 endchoice
 
 config DISCONTIGMEM
        def_bool y
        depends on (!SELECT_MEMORY_MODEL && ARCH_DISCONTIGMEM_ENABLE) || DISCONTIGMEM_MANUAL
 
+config SPARSEMEM
+       def_bool y
+       depends on SPARSEMEM_MANUAL
+
 config FLATMEM
        def_bool y
-       depends on !DISCONTIGMEM || FLATMEM_MANUAL
+       depends on (!DISCONTIGMEM && !SPARSEMEM) || FLATMEM_MANUAL
+
+config FLAT_NODE_MEM_MAP
+       def_bool y
+       depends on !SPARSEMEM
 
 #
 # Both the NUMA code and DISCONTIGMEM use arrays of pg_data_t's
@@ -56,4 +88,26 @@ config NEED_MULTIPLE_NODES
 
 config HAVE_MEMORY_PRESENT
        def_bool y
-       depends on ARCH_HAVE_MEMORY_PRESENT
+       depends on ARCH_HAVE_MEMORY_PRESENT || SPARSEMEM
+
+#
+# SPARSEMEM_EXTREME (which is the default) does some bootmem
+# allocations when memory_present() is called.  If this can not
+# be done on your architecture, select this option.  However,
+# statically allocating the mem_section[] array can potentially
+# consume vast quantities of .bss, so be careful.
+#
+# This option will also potentially produce smaller runtime code
+# with gcc 3.4 and later.
+#
+config SPARSEMEM_STATIC
+       def_bool n
+
+#
+# Architectecture platforms which require a two level mem_section in SPARSEMEM
+# must select this option. This is usually for architecture platforms with
+# an extremely sparse physical address space.
+#
+config SPARSEMEM_EXTREME
+       def_bool y
+       depends on SPARSEMEM && !SPARSEMEM_STATIC