Apologies for bumping. I also should give a better description:
This patch introduces a configuration option for the default cryptographic compression algorithm used by zswap. Previous to this patch, one would use the default compression algorithm until changed from userspace. This patch allows a compilation time change, which will remain the default from boot until changed.
On Sat, Jun 30, 2018 at 11:56 PM Will Ziener-Dignazio <wdignazio@xxxxxxxxx> wrote:
- Add Kconfig option for default compressor algorithm
- Add the deflate and LZ4 algorithms as default options
Signed-off-by: Will Ziener-Dignazio <wdignazio@xxxxxxxxx>
---
mm/Kconfig | 35 ++++++++++++++++++++++++++++++++++-
mm/zswap.c | 11 ++++++++++-
2 files changed, 44 insertions(+), 2 deletions(-)
diff --git a/mm/Kconfig b/mm/Kconfig
index ce95491abd6a..09df6650e96a 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -535,7 +535,6 @@ config MEM_SOFT_DIRTY
config ZSWAP
bool "Compressed cache for swap pages (EXPERIMENTAL)"
depends on FRONTSWAP && CRYPTO=y
- select CRYPTO_LZO
select ZPOOL
default n
help
@@ -552,6 +551,40 @@ config ZSWAP
they have not be fully explored on the large set of potential
configurations and workloads that exist.
+choice
+ prompt "Compressed cache cryptographic compression algorithm"
+ default ZSWAP_COMPRESSOR_DEFAULT_LZO
+ depends on ZSWAP
+ help
+ The default cyptrographic compression algorithm to use for
+ compressed swap pages.
+
+config ZSWAP_COMPRESSOR_DEFAULT_LZO
+ bool "lzo"
+ select CRYPTO_LZO
+ help
+ This option sets the default zswap compression algorithm to LZO,
+ the Lempel-Ziv-Oberhumer algorithm. This algorthm focuses on
+ decompression speed, but has a lower compression ratio.
+
+config ZSWAP_COMPRESSOR_DEFAULT_DEFLATE
+ bool "deflate"
+ select CRYPTO_DEFLATE
+ help
+ This option sets the default zswap compression algorithm to DEFLATE.
+ This algorithm balances compression and decompression speed to
+ compresstion ratio.
+
+config ZSWAP_COMPRESSOR_DEFAULT_LZ4
+ bool "lz4"
+ select CRYPTO_LZ4
+ help
+ This option sets the default zswap compression algorithm to LZ4.
+ This algorithm focuses on high compression speed, but has a lower
+ compression ratio and decompression speed.
+
+endchoice
+
config ZPOOL
tristate "Common API for compressed memory storage"
default n
diff --git a/mm/zswap.c b/mm/zswap.c
index 7d34e69507e3..30f9f25da4d0 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -91,7 +91,16 @@ static struct kernel_param_ops zswap_enabled_param_ops = {
module_param_cb(enabled, &zswap_enabled_param_ops, &zswap_enabled, 0644);
/* Crypto compressor to use */
-#define ZSWAP_COMPRESSOR_DEFAULT "lzo"
+#if defined(CONFIG_ZSWAP_COMPRESSOR_DEFAULT_LZO)
+ #define ZSWAP_COMPRESSOR_DEFAULT "lzo"
+#elif defined(CONFIG_ZSWAP_COMPRESSOR_DEFAULT_DEFLATE)
+ #define ZSWAP_COMPRESSOR_DEFAULT "deflate"
+#elif defined(CONFIG_ZSWAP_COMPRESSOR_DEFAULT_LZ4)
+ #define ZSWAP_COMPRESSOR_DEFAULT "lz4"
+#else
+ #error "Default zswap compression algorithm not defined."
+#endif
+
static char *zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
static int zswap_compressor_param_set(const char *,
const struct kernel_param *);
--
2.18.0
Bytes Go In, Words Go Out
