deswappify-auto
Automatically fetch swapped pages to physical memory when enough memory is available.
The code is inspired by https://gist.github.com/WGH-/91260f6d65db88be2c847053c49be5ae and the discussion on https://unix.stackexchange.com/questions/45673/how-can-swapoff-be-that-slow.
It is ment to be used as a daemon on linux. It continuously scans the memory and load situation and performs a deswap operation when there the situation allows (enough available memory and not too many active processes). This might be seen as a workaround for high swap usages after resume from hibernation, even if there is enough physical memory available.
Dependencies
The script has been developed in python 3.5 (it might run also with python 2.7).
Recommended python packages are systemd (for logging) and psutil (for setting an appropriate ionice level). If these packages are not installed, the functionality is slightly limited.
The script expects the linux commands free, swapoff and swapon to be in PATH, the latter two are optional and only used if -e option is set.
Obviously, the script has to be run with root privileges.
Help
Help is available via deswappify_auto.py -h:
usage: deswappify_auto [-h] [--version] [-v {error,warning,info,dump}]
[-m MEM_THRESHOLD] [-s MAX_ACCEPTED_SWAP_SIZE]
[-p POLL_PROC_SWAP_INTERVAL]
[-P POLL_PROC_ACTIVE_INTERVAL] [-b IDLE_AFTER_BUSY]
[-c IDLE_AFTER_COMPLETED] [-a MAX_ACTIVE_PROCESSES]
[-n] [-l] [-e] [-j NUM_PARALLEL] [-t SPAWN_TIMEOUT]
[-d] [--pc_during_deswap PC_DURING_DESWAP]
[--pc_during_idle PC_DURING_IDLE]
[pids [pids ...]]
positional arguments:
pids If pids are specified, the program is run in one-shot
mode. Otherwise it's run as a daemon. (default: [])
optional arguments:
-h, --help show this help message and exit
--version show program's version number and exit
-v {error,warning,info,dump}, --verbose {error,warning,info,dump}
set verbosity (default: warning)
-m MEM_THRESHOLD, --mem_threshold MEM_THRESHOLD
set minimal amount of extra memory which should be
available after deswapping. Sizes can be suffixed with
k,M,G and T for bytes and with % for percentage of
physical memory. (default: 25%)
-s MAX_ACCEPTED_SWAP_SIZE, --max_accepted_swap_size MAX_ACCEPTED_SWAP_SIZE
set maximum amount of swap size which is acceptable
before leaving idle state. Sizes can be suffixed with
k,M,G and T for bytes and with % for percentage of
physical memory. (default: 100M)
-p POLL_PROC_SWAP_INTERVAL, --poll_proc_swap_interval POLL_PROC_SWAP_INTERVAL
minimum number of seconds between two polls of the
/proc directory for swap information. (default: 60)
-P POLL_PROC_ACTIVE_INTERVAL, --poll_proc_active_interval POLL_PROC_ACTIVE_INTERVAL
minimum number of seconds between two polls of the
/proc directory for active process information.
(default: 3)
-b IDLE_AFTER_BUSY, --idle_after_busy IDLE_AFTER_BUSY
number of seconds to sleep after system busy
detection. (default: 5)
-c IDLE_AFTER_COMPLETED, --idle_after_completed IDLE_AFTER_COMPLETED
number of seconds to sleep after successful
deswappify. (default: 60)
-a MAX_ACTIVE_PROCESSES, --max_active_processes MAX_ACTIVE_PROCESSES
maximum number of active processes for system idle
detection. (default: 4)
-n, --avoid_renicing avoid renicing this process. (default: False)
-l, --systemd_logger use systemd logger instead of python stream logger.
(default: False)
-e, --swapoffon if given, a swapoff -a followed by a swapon -a will be
issued after successfully completing a deswapping.
(default: False)
-j NUM_PARALLEL, --num_parallel NUM_PARALLEL
Number of parallel readers. In theory, more readers
should be more efficient on HDD's because the parallel
accesses can be sorted. (default: 1)
-t SPAWN_TIMEOUT, --spawn_timeout SPAWN_TIMEOUT
Timeout for spawned processes. Only available in
python3. (default: 0)
-d, --develop use in development mode, after a possible bug is
detected, the application exits. (default: False)
--pc_during_deswap PC_DURING_DESWAP
Optimize swap read-ahead in /proc/sys/vm/page-cluster
during deswap operation. This is the value to be used
during deswappifying. The actual number of bytes can
be calculated by pagesize*2^value. For page sizes of 4
kB, the default value of 16 is 256 MB. Use negative
sizes to not modify the value stored in
/proc/sys/vm/page-cluster. (default: 16)
--pc_during_idle PC_DURING_IDLE
Optimize swap read-ahead in /proc/sys/vm/page-cluster
during deswap operation. This is the value to be used
during idle operation. Use negative arguments to
return to the original value stored in
/proc/sys/vm/page-cluster. (default: -1)