|
HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|
|
NAME | SYNOPSIS | DESCRIPTION | CONFIGURATION DIRECTORIES AND PRECEDENCE | [OOM] SECTION OPTIONS | SEE ALSO | NOTES | COLOPHON |
|
|
|
OOMD.CONF(5) oomd.conf OOMD.CONF(5)
oomd.conf, oomd.conf.d - Global systemd-oomd configuration files
/etc/systemd/oomd.conf
/run/systemd/oomd.conf
/usr/local/lib/systemd/oomd.conf
/usr/lib/systemd/oomd.conf
/etc/systemd/oomd.conf.d/*.conf
/run/systemd/oomd.conf.d/*.conf
/usr/local/lib/systemd/oomd.conf.d/*.conf
/usr/lib/systemd/oomd.conf.d/*.conf
These files configure the various parameters of the systemd(1)
userspace out-of-memory (OOM) killer, systemd-oomd.service(8). See
systemd.syntax(7) for a general description of the syntax.
The default configuration is set during compilation, so
configuration is only needed when it is necessary to deviate from
those defaults. The main configuration file is loaded from one of
the listed directories in order of priority, only the first file
found is used: /etc/systemd/, /run/systemd/,
/usr/local/lib/systemd/ [1], /usr/lib/systemd/. The vendor version
of the file contains commented out entries showing the defaults as
a guide to the administrator. Local overrides can also be created
by creating drop-ins, as described below. The main configuration
file can also be edited for this purpose (or a copy in /etc/ if it
is shipped under /usr/), however using drop-ins for local
configuration is recommended over modifications to the main
configuration file.
In addition to the main configuration file, drop-in configuration
snippets are read from /usr/lib/systemd/*.conf.d/,
/usr/local/lib/systemd/*.conf.d/, and /etc/systemd/*.conf.d/.
Those drop-ins have higher precedence and override the main
configuration file. Files in the *.conf.d/ configuration
subdirectories are sorted by their filename in lexicographic
order, regardless of in which of the subdirectories they reside.
When multiple files specify the same option, for options which
accept just a single value, the entry in the file sorted last
takes precedence, and for options which accept a list of values,
entries are collected as they occur in the sorted files.
When packages need to customize the configuration, they can
install drop-ins under /usr/. Files in /etc/ are reserved for the
local administrator, who may use this logic to override the
configuration files installed by vendor packages. Drop-ins have to
be used to override package drop-ins, since the main configuration
file has lower precedence. It is recommended to prefix all
filenames in those subdirectories with a two-digit number and a
dash, to simplify the ordering. This also defines a concept of
drop-in priorities to allow OS vendors to ship drop-ins within a
specific range lower than the range used by users. This should
lower the risk of package drop-ins overriding accidentally
drop-ins defined by users. It is recommended to use the range
10-40 for drop-ins in /usr/ and the range 60-90 for drop-ins in
/etc/ and /run/, to make sure that local and transient drop-ins
take priority over drop-ins shipped by the OS vendor.
To disable a configuration file supplied by the vendor, the
recommended way is to place a symlink to /dev/null in the
configuration directory in /etc/, with the same filename as the
vendor configuration file.
The following options are available in the [OOM] section:
SwapUsedLimit=
Sets the limit for memory and swap usage on the system before
systemd-oomd will take action. If the fraction of memory used
and the fraction of swap used on the system are both more than
what is defined here, systemd-oomd will act on eligible
descendant control groups with swap usage greater than 5% of
total swap, starting from the ones with the highest swap
usage. Which control groups are monitored and what action gets
taken depends on what the unit has configured for
ManagedOOMSwap=. Takes a value specified in percent (when
suffixed with "%"), permille ("‰") or permyriad ("‱"), between
0% and 100%, inclusive. Defaults to 90%.
Added in version 247.
DefaultMemoryPressureLimit=
Sets the limit for memory pressure on the unit's control group
before systemd-oomd will take action. A unit can override this
value with ManagedOOMMemoryPressureLimit=. The memory pressure
for this property represents the fraction of time in a 10
second window in which all tasks in the control group were
delayed. For each monitored control group, if the memory
pressure on that control group exceeds the limit set for
longer than the duration set by
DefaultMemoryPressureDurationSec=, systemd-oomd will act on
eligible descendant control groups, starting from the ones
with the most reclaim activity to the least reclaim activity.
Which control groups are monitored and what action gets taken
depends on what the unit has configured for
ManagedOOMMemoryPressure=. Takes a fraction specified in the
same way as SwapUsedLimit= above. Defaults to 60%.
Added in version 247.
DefaultMemoryPressureDurationSec=
Sets the amount of time a unit's control group needs to have
exceeded memory pressure limits before systemd-oomd will take
action. A unit can override this value with
ManagedOOMMemoryPressureDurationSec=. Memory pressure limits
are defined by DefaultMemoryPressureLimit= and
ManagedOOMMemoryPressureLimit=. Must be set to 0, or at least
1 second. Defaults to 30 seconds when unset or 0.
Added in version 248.
systemd(1), systemd.resource-control(5), systemd-oomd.service(8),
oomctl(1)
1. 💣💥🧨💥💥💣 Please note that those configuration files must
be available at all times. If /usr/local/ is a separate
partition, it may not be available during early boot, and must
not be used for configuration.
This page is part of the systemd (systemd system and service
manager) project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a
bug report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
This page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2025-08-11. (At that
time, the date of the most recent commit that was found in the
repository was 2025-08-11.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
systemd 258~rc2 OOMD.CONF(5)
Pages that refer to this page: oomctl(1), systemd.resource-control(5), systemd.directives(7), systemd.index(7), systemd-oomd.service(8)
|
HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|