--help¶

Print help message and exit.

--version¶

Print version information and exit.

--config¶

Get options from the configuration file instead of the cmdline.

--env¶

Get options from the environment variables instead of the cmdline.

--stats¶

Get statistics and current settings of the ZSwap kernel module.

Supported values:

•

0 (default) - print everything: kernel module settings, usage summary, and debug information.

•

1 - print kernel module settings.

•

2 - print kernel module usage summary.

•

3 - print kernel module debug information.

-e, --enabled¶

Enable or disable the ZSwap kernel module.

Supported values: Y, N.

-s, --same_filled_pages_enabled¶

Enable or disable memory pages deduplication.

Supported values: Y, N.

-p, --max_pool_percent¶

The maximum percentage of memory that the compressed pool can occupy.

Supported values: integer from 1 to 100.

-c, --compressor¶

The algorithm used to compress memory pages.

Supported values: depends on the kernel build time configuration.

-z, --zpool¶

The kernel’s zpool type.

Supported values: depends on the kernel build time configuration.

-a, --accept_threshold_percent¶

The threshold at which ZSwap would start accepting pages again after it became full.

Supported values: integer from 1 to 100.

-n, --non_same_filled_pages_enabled¶

Enable or disable accepting non same filled memory pages.

Supported values: Y, N.

-x, --exclusive_loads¶

Enable or disable entries invalidation when memory pages are loaded from compressed pool.

Supported values: Y, N.

-r, --shrinker_enabled¶

Enable or disable pool shrinking based on memory pressure.

Supported values: Y, N.

Supported options¶

•

ZSWAP_ENABLED_VALUE - enable or disable the ZSwap kernel module.

•

ZSWAP_SAME_FILLED_PAGES_ENABLED_VALUE - enable or disable memory pages deduplication.

•

ZSWAP_MAX_POOL_PERCENT_VALUE - the maximum percentage of memory that the compressed pool can occupy.

•

ZSWAP_COMPRESSOR_VALUE - the algorithm used to compress memory pages.

•

ZSWAP_ZPOOL_VALUE - the kernel’s zpool type.

•

ZSWAP_ACCEPT_THRESHOLD_PERCENT_VALUE - the threshold at which ZSwap would start accepting pages again after it became full.

•

ZSWAP_NON_SAME_FILLED_PAGES_ENABLED_VALUE - enable or disable accepting non same filled memory pages.

•

ZSWAP_EXCLUSIVE_LOADS_VALUE - enable or disable entries invalidation when memory pages are loaded from compressed pool.

•

ZSWAP_SHRINKER_ENABLED_VALUE - enable or disable pool shrinking based on memory pressure.

Forwarding options¶

Export the environment variables using the export command:

export ZSWAP_ENABLED_VALUE=Y
export ZSWAP_SAME_FILLED_PAGES_ENABLED_VALUE=Y
export ZSWAP_MAX_POOL_PERCENT_VALUE=60
export ZSWAP_COMPRESSOR_VALUE=lzo
export ZSWAP_ZPOOL_VALUE=z3fold
export ZSWAP_ACCEPT_THRESHOLD_PERCENT_VALUE=90
export ZSWAP_NON_SAME_FILLED_PAGES_ENABLED_VALUE=Y
export ZSWAP_EXCLUSIVE_LOADS_VALUE=Y
export ZSWAP_SHRINKER_ENABLED_VALUE=Y
    

Start the application with the --env command-line argument:

sudo zswap-cli --env
    

Note that most distributions are configured by default not to pass user-defined ENV settings when using sudo. In such cases, you can explicitly specify them all in one command:

sudo ZSWAP_ENABLED_VALUE=Y \


     ZSWAP_SAME_FILLED_PAGES_ENABLED_VALUE=Y \


     ZSWAP_MAX_POOL_PERCENT_VALUE=60 \


     ZSWAP_COMPRESSOR_VALUE=lzo \


     ZSWAP_ZPOOL_VALUE=z3fold \


     ZSWAP_ACCEPT_THRESHOLD_PERCENT_VALUE=90 \


     ZSWAP_NON_SAME_FILLED_PAGES_ENABLED_VALUE=Y \


     ZSWAP_EXCLUSIVE_LOADS_VALUE=Y \


     ZSWAP_SHRINKER_ENABLED_VALUE=Y \


     zswap-cli --env
    

Supported options¶

•

enabled - enable or disable the ZSwap kernel module.

•

same_filled_pages_enabled - enable or disable memory pages deduplication.

•

max_pool_percent - the maximum percentage of memory that the compressed pool can occupy.

•

compressor - the algorithm used to compress memory pages.

•

zpool - the kernel’s zpool type.

•

accept_threshold_percent - the threshold at which ZSwap would start accepting pages again after it became full.

•

non_same_filled_pages_enabled - enable or disable accepting non same filled memory pages.

•

exclusive_loads - enable or disable entries invalidation when memory pages are loaded from compressed pool.

•

shrinker_enabled - enable or disable pool shrinking based on memory pressure.

Forwarding options¶

Create a configuration file:

[zswap]
enabled=Y
same_filled_pages_enabled=Y
max_pool_percent=60
compressor=lzo
zpool=z3fold
accept_threshold_percent=90
non_same_filled_pages_enabled=Y
exclusive_loads=Y
shrinker_enabled=Y
    

Start the application with the --config command-line argument:

sudo zswap-cli --config /path/to/zswap-cli.conf
    

Changing settings¶

All settings are stored in the /etc/zswap-cli/zswap-cli.conf configuration file. It uses standard key-value syntax and can be edited by the user.

Enabling unit¶

Enable the systemd unit to allow it to run at system startup:

sudo systemctl enable --now zswap-cli.service
    

Disabling unit¶

Disable the systemd unit and stop it from running at system startup:

sudo systemctl disable zswap-cli.service
    

Running unit¶

It is also possible to start the systemd unit without adding it to startup.

Start the unit and enable ZSwap:

sudo systemctl start zswap-cli.service
    

Stop the unit and disable ZSwap:

sudo systemctl stop zswap-cli.service