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 un‐
       responsive 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 (high‐
       est 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  (de‐
       fault 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 val‐
       ue 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
       removed in earlyoom v1.7, ignored for compatibility

   -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.

       To   actually   see   the   notifications  in  your  GUI  session,  you  need  to  have  systembus-notify
       (https://github.com/rfjakob/systembus-notify) running as your user.

   -N /PATH/TO/SCRIPT
       Run the given script for each process killed.  Must be an absolute path.

       Within the script, information about the killed process can be obtained  via  the  following  environment
       variables:

              EARLYOOM_PID     Process PID
              EARLYOOM_NAME    Process name truncated to 16 bytes (as reported in /proc/PID/comm)
              EARLYOOM_UID     UID of the user running the process

       WARNING: EARLYOOM_NAME can contain spaces, newlines, special characters and is controlled by the user, or
       it can be empty!  Make sure that your notification script can handle that!

   -g
       Kill all processes that have same process group id (PGID) as the process with excessive memory usage.

       For  example,  with  this flag turned on, the whole application will be killed when one of its subprocess
       consumes too much memory (as long as they all have the same PGID, of course).

       Enable this flag when completely cleaning up the “entire application” is more desirable, and you are sure
       that the application puts all its processes in the same PGID.

       Note that some desktop environments (GNOME, for example) put all desktop application in the same  process
       group  as  gnome-shell.   earlyoom  might kill all such processes including gnome-shell when this flag is
       turned on.

       Be sure to check how your environment behaves beforehand.  Use

              pstree -gT

       to show all processes with the PGID in brackets.

   --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)