Provided by: earlyoom_1.6.2-1_amd64 
NAME
earlyoom - Early OOM Daemon
SYNOPSIS
earlyoom [OPTION]...
DESCRIPTION
The oom-killer generally has a bad reputation among Linux users. One may have to sit in
front of an unresponsive system, listening to the grinding disk for minutes, and press the
reset button to quickly get back to what one was doing after running out of patience.
earlyoom checks the amount of available memory and free swap up to 10 times a second (less
often if there is a lot of free memory). If both memory and swap are below 10%, it will
kill the largest process (highest oom_score). The percentage value is configurable via
command line arguments.
If there is a failure when trying to kill a process, earlyoom sleeps for 1 second to limit
log spam due to recurring errors.
OPTIONS
-m PERCENT[,KILL_PERCENT]
set available memory minimum to PERCENT of total (default 10 %).
earlyoom starts sending SIGTERM once both memory and swap are below their respective
PERCENT setting. It sends SIGKILL once both are below their respective KILL_PERCENT
setting (default PERCENT/2).
Use the same value for PERCENT and KILL_PERCENT if you always want to use SIGKILL.
Examples:
earlyoom # sets PERCENT=10, KILL_PERCENT=5
earlyoom -m 30 # sets PERCENT=30, KILL_PERCENT=15
earlyoom -m 20,18 # sets PERCENT=20, KILL_PERCENT=18
-s PERCENT[,KILL_PERCENT]
set free swap minimum to PERCENT of total (default 10 %). Send SIGKILL if at or below
KILL_PERCENT (default PERCENT/2), otherwise SIGTERM.
You can use -s 100 to have earlyoom effectively ignore swap usage: Processes are killed
once available memory drops below the configured minimum, no matter how much swap is free.
Use the same value for PERCENT and KILL_PERCENT if you always want to use SIGKILL.
-M SIZE[,KILL_SIZE]
As an alternative to specifying a percentage of total memory, -M sets the available memory
minimum to SIZE KiB. The value is internally converted to a percentage. If you pass both
-M and -m, the lower value is used. Example: Reserve 10% of RAM but at most 1 GiB:
earlyoom -m 10 -M 1048576
earlyoom sends SIGKILL if at or below KILL_SIZE (default SIZE/2), otherwise SIGTERM.
-S SIZE[,KILL_SIZE]
As an alternative to specifying a percentage of total swap, -S sets the free swap minimum
to SIZE KiB. The value is internally converted to a percentage. If you pass both -S and
-s, the lower value is used.
Send SIGKILL if at or below KILL_SIZE (default SIZE/2), otherwise SIGTERM.
-k
removed in earlyoom v1.2, ignored for compatibility
-i
user-space oom killer should ignore positive oom_score_adj values
-d
enable debugging messages
-v
print version information and exit
-r INTERVAL
Time between printing periodic memory reports, in seconds (default 1.0). A memory report
looks like this:
mem avail: 21790 of 23909 MiB (91.14%), swap free: 0 of 0 MiB ( 0.00%)
Set to 3600 to print a report every hour, to 86400 to print once a day etc. Set to 0 to
disable printing periodic memory reports. Free memory monitoring and low-memory killing
runs independently of this option at an adaptive poll rate that only depends on free
memory. Due to the adaptive poll rate, when there is a lot of free memory, the actual
interval may be up to 1 second longer than the setting.
-p
Increase earlyoom’s priority: set niceness of earlyoom to -20 and oom_score_adj to -100.
When earlyoom is run through its default systemd service, the -p switch doesn’t work. To
achieve the same effect, enter the following three lines into sudo systemctl edit
earlyoom:
[Service]
OOMScoreAdjust=-100
Nice=-20
-n
Enable notifications via d-bus.
--prefer REGEX
prefer killing processes matching REGEX (adds 300 to oom_score)
--avoid REGEX
avoid killing processes matching REGEX (subtracts 300 from oom_score)
--dryrun
dry run (do not kill any processes)
-h, --help
this help text
EXIT STATUS
0: Successful program execution.
1: Other error - inspect message for details
2: Switch conflict.
4: Could not cd to /proc
5: Could not open proc
7: Could not open /proc/sysrq-trigger
13: Unknown options.
14: Wrong parameters for other options.
15: Wrong parameters for memory threshold.
16: Wrong parameters for swap threshold.
102: Could not open /proc/meminfo
103: Could not read /proc/meminfo
104: Could not find a specific entry in /proc/meminfo
105: Could not convert number when parse the contents of /proc/meminfo
Why not trigger the kernel oom killer?
Earlyoom does not use echo f > /proc/sysrq-trigger because the Chrome people made their
browser always be the first (innocent!) victim by setting oom_score_adj very high.
Instead, earlyoom finds out itself by reading through /proc/*/status (actually
/proc/*/statm, which contains the same information but is easier to parse
programmatically).
Additionally, in recent kernels (tested on 4.0.5), triggering the kernel oom killer
manually may not work at all. That is, it may only free some graphics memory (that will
be allocated immediately again) and not actually kill any process.
MEMORY USAGE
About 2 MiB VmRSS. All memory is locked using mlockall() to make sure earlyoom does not
slow down in low memory situations.
BUGS
If there is zero total swap on earlyoom startup, any -S (uppercase “S”) values are
ignored, a warning is printed, and default swap percentages are used.
For processes matched by --prefer, negative oom_score_adj values are not taken into
account, and the process gets an effective oom_score of at least 300. See
https://github.com/rfjakob/earlyoom/issues/159 for details.
AUTHOR
The author of earlyoom is Jakob Unterwurzacher ⟨jakobunt@gmail.com⟩.
This manual page was written by Yangfl ⟨mmyangfl@gmail.com⟩, for the Debian project (and
may be used by others).
earlyoom(1)