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
       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)