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-rw-r--r--mm/Kconfig17
-rw-r--r--mm/Makefile1
2 files changed, 18 insertions, 0 deletions
diff --git a/mm/Kconfig b/mm/Kconfig
index e338407f1225..2613c910935a 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -379,3 +379,20 @@ config CLEANCACHE
in a negligible performance hit.
If unsure, say Y to enable cleancache
+
+config FRONTSWAP
+ bool "Enable frontswap to cache swap pages if tmem is present"
+ depends on SWAP
+ default n
+ help
+ Frontswap is so named because it can be thought of as the opposite
+ of a "backing" store for a swap device. The data is stored into
+ "transcendent memory", memory that is not directly accessible or
+ addressable by the kernel and is of unknown and possibly
+ time-varying size. When space in transcendent memory is available,
+ a significant swap I/O reduction may be achieved. When none is
+ available, all frontswap calls are reduced to a single pointer-
+ compare-against-NULL resulting in a negligible performance hit
+ and swap data is stored as normal on the matching swap device.
+
+ If unsure, say Y to enable frontswap.
diff --git a/mm/Makefile b/mm/Makefile
index 50ec00ef2a0e..306742a28266 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_HAVE_MEMBLOCK) += memblock.o
obj-$(CONFIG_BOUNCE) += bounce.o
obj-$(CONFIG_SWAP) += page_io.o swap_state.o swapfile.o thrash.o
+obj-$(CONFIG_FRONTSWAP) += frontswap.o
obj-$(CONFIG_HAS_DMA) += dmapool.o
obj-$(CONFIG_HUGETLBFS) += hugetlb.o
obj-$(CONFIG_NUMA) += mempolicy.o