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-rw-r--r--mm/Kconfig13
1 files changed, 13 insertions, 0 deletions
diff --git a/mm/Kconfig b/mm/Kconfig
index 391ffc5..f35a550 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -111,3 +111,16 @@ config SPARSEMEM_STATIC
config SPARSEMEM_EXTREME
def_bool y
depends on SPARSEMEM && !SPARSEMEM_STATIC
+
+# 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's debug spinlock_t is too large for the 32-bit struct page.
+#
+config SPLIT_PTLOCK_CPUS
+ int
+ default "4096" if ARM && !CPU_CACHE_VIPT
+ default "4096" if PARISC && DEBUG_SPINLOCK && !64BIT
+ default "4"
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