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-rw-r--r--mm/Kconfig21
1 files changed, 21 insertions, 0 deletions
diff --git a/mm/Kconfig b/mm/Kconfig
index 391ffc54d13..21eb51d4da8 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -111,3 +111,24 @@ config SPARSEMEM_STATIC
config SPARSEMEM_EXTREME
def_bool y
depends on SPARSEMEM && !SPARSEMEM_STATIC
+
+# eventually, we can have this option just 'select SPARSEMEM'
+config MEMORY_HOTPLUG
+ bool "Allow for memory hot-add"
+ depends on SPARSEMEM && HOTPLUG && !SOFTWARE_SUSPEND
+
+comment "Memory hotplug is currently incompatible with Software Suspend"
+ depends on SPARSEMEM && HOTPLUG && SOFTWARE_SUSPEND
+
+# Heavily threaded applications may benefit from splitting the mm-wide
+# page_table_lock, so that faults on different parts of the user address
+# space can be handled with less contention: split it at this NR_CPUS.
+# Default to 4 for wider testing, though 8 might be more appropriate.
+# ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock.
+# PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes.
+#
+config SPLIT_PTLOCK_CPUS
+ int
+ default "4096" if ARM && !CPU_CACHE_VIPT
+ default "4096" if PARISC && !PA20
+ default "4"