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authorSeth Jennings <sjenning@linux.vnet.ibm.com>2013-07-10 16:05:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-10 18:11:34 -0700
commit2b2811178e85553405b86e3fe78357b9b95889ce (patch)
tree0d5b12e7013be79a8e89d145a46bc32e82f86a81 /mm/Kconfig
parent4e2e2770b1529edc5849c86b29a6febe27e2f083 (diff)
zswap: add to mm/
zswap is a thin backend for frontswap that takes pages that are in the process of being swapped out and attempts to compress them and store them in a RAM-based memory pool. This can result in a significant I/O reduction on the swap device and, in the case where decompressing from RAM is faster than reading from the swap device, can also improve workload performance. It also has support for evicting swap pages that are currently compressed in zswap to the swap device on an LRU(ish) basis. This functionality makes zswap a true cache in that, once the cache is full, the oldest pages can be moved out of zswap to the swap device so newer pages can be compressed and stored in zswap. This patch adds the zswap driver to mm/ Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Acked-by: Rik van Riel <riel@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Robert Jennings <rcj@linux.vnet.ibm.com> Cc: Jenifer Hopper <jhopper@us.ibm.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dave Hansen <dave@sr71.net> Cc: Joe Perches <joe@perches.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Cody P Schafer <cody@linux.vnet.ibm.com> Cc: Hugh Dickens <hughd@google.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/Kconfig')
-rw-r--r--mm/Kconfig20
1 files changed, 20 insertions, 0 deletions
diff --git a/mm/Kconfig b/mm/Kconfig
index 45503ed5f3a..8028dcc6615 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -488,6 +488,26 @@ config ZBUD
deterministic reclaim properties that make it preferable to a higher
density approach when reclaim will be used.
+config ZSWAP
+ bool "Compressed cache for swap pages (EXPERIMENTAL)"
+ depends on FRONTSWAP && CRYPTO=y
+ select CRYPTO_LZO
+ select ZBUD
+ default n
+ help
+ A lightweight compressed cache for swap pages. It takes
+ pages that are in the process of being swapped out and attempts to
+ compress them into a dynamically allocated RAM-based memory pool.
+ This can result in a significant I/O reduction on swap device and,
+ in the case where decompressing from RAM is faster that swap device
+ reads, can also improve workload performance.
+
+ This is marked experimental because it is a new feature (as of
+ v3.11) that interacts heavily with memory reclaim. While these
+ interactions don't cause any known issues on simple memory setups,
+ they have not be fully explored on the large set of potential
+ configurations and workloads that exist.
+
config MEM_SOFT_DIRTY
bool "Track memory changes"
depends on CHECKPOINT_RESTORE && HAVE_ARCH_SOFT_DIRTY