treewide: Add SPDX license identifier - Makefile/Kconfig

[linux-2.6-microblaze.git] / mm / Kconfig

diff --git a/mm/Kconfig b/mm/Kconfig
index c5124c2..f0c76ba 100644 (file)
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 
 menu "Memory Management options"
 
@@ -11,23 +12,24 @@ choice
        default DISCONTIGMEM_MANUAL if ARCH_DISCONTIGMEM_DEFAULT
        default SPARSEMEM_MANUAL if ARCH_SPARSEMEM_DEFAULT
        default FLATMEM_MANUAL
+       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 selected by the architecture
+         configuration. This is normal.
 
 config FLATMEM_MANUAL
        bool "Flat Memory"
        depends on !(ARCH_DISCONTIGMEM_ENABLE || ARCH_SPARSEMEM_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 a 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".
+         This option is best suited for non-NUMA systems with
+         flat address space. The FLATMEM is the most efficient
+         system in terms of performance and resource consumption
+         and it is the best option for smaller systems.
+
+         For systems that have holes in their physical address
+         spaces and for features like NUMA and memory hotplug,
+         choose "Sparse Memory"
 
          If unsure, choose this option (Flat Memory) over any other.
 
@@ -38,29 +40,26 @@ config DISCONTIGMEM_MANUAL
          This option provides enhanced support for discontiguous
          memory systems, over FLATMEM.  These systems have holes
          in their physical address spaces, and this option provides
-         more efficient handling of these holes.  However, the vast
-         majority of hardware has quite flat address spaces, and
-         can have degraded performance from the extra overhead that
-         this option imposes.
+         more efficient handling of these holes.
 
-         Many NUMA configurations will have this as the only option.
+         Although "Discontiguous Memory" is still used by several
+         architectures, it is considered deprecated in favor of
+         "Sparse Memory".
 
-         If unsure, choose "Flat Memory" over this option.
+         If unsure, choose "Sparse 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.
+         memory hot-plug systems.  This is normal.
 
-         For many other systems, this will be an alternative to
-         "Discontiguous Memory".  This option provides some potential
-         performance benefits, along with decreased code complexity,
-         but it is newer, and more experimental.
+         This option provides efficient support for systems with
+         holes is their physical address space and allows memory
+         hot-plug and hot-remove.
 
-         If unsure, choose "Discontiguous Memory" or "Flat Memory"
-         over this option.
+         If unsure, choose "Flat Memory" over this option.
 
 endchoice