Merge tag 'stable/frontswap.v16-tag' of git://git.kernel.org/pub/scm/linux/kernel...

[karo-tx-linux.git] / mm / Kconfig

diff --git a/mm/Kconfig b/mm/Kconfig
index b2176374b98e5e678ec93acda28cc0891d1c3717..82fed4eb2b6fe39cfd0476afe46e9589e02b386f 100644 (file)
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -389,3 +389,20 @@ 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.