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-rw-r--r--mm/Kconfig17
1 files changed, 17 insertions, 0 deletions
diff --git a/mm/Kconfig b/mm/Kconfig
index a25c5476b3ad4..4a4e7b63d30a8 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -887,8 +887,25 @@ config READ_ONLY_THP_FOR_FS
support of file THPs will be developed in the next few release
cycles.
+config NO_PAGE_MAPCOUNT
+ bool "No per-page mapcount (EXPERIMENTAL)"
+ help
+ Do not maintain per-page mapcounts for pages part of larger
+ allocations, such as transparent huge pages.
+
+ When this config option is enabled, some interfaces that relied on
+ this information will rely on less-precise per-allocation information
+ instead: for example, using the average per-page mapcount in such
+ a large allocation instead of the per-page mapcount.
+
+ EXPERIMENTAL because the impact of some changes is still unclear.
+
endif # TRANSPARENT_HUGEPAGE
+# simple helper to make the code a bit easier to read
+config PAGE_MAPCOUNT
+ def_bool !NO_PAGE_MAPCOUNT
+
#
# The architecture supports pgtable leaves that is larger than PAGE_SIZE
#