364 lines
9.6 KiB
Plaintext
364 lines
9.6 KiB
Plaintext
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This is nohang config file.
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Redesign of this config in progress.
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Lines starting with #, tabs and spaces are comments.
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Lines starting with $ contain obligatory parameters.
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Lines starting with @ contain optional parameters.
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The configuration includes the following sections:
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1. Memory levels to respond to as an OOM threat
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2. Response on PSI memory metrics
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3. The frequency of checking the level of available memory
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(and CPU usage)
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4. The prevention of killing innocent victims
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5. Impact on the badness of processes via matching their
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- names,
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- cmdlines and
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- UIDs
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with regular expressions
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6. The execution of a specific command instead of sending the
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SIGTERM signal
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7. GUI notifications:
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- OOM prevention results and
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- low memory warnings
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8. Output verbosity
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9. Misc
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Just read the description of the parameters and edit the values.
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Please restart the program after editing the config.
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#####################################################################
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1. Thresholds below which a signal should be sent to the victim
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Sets the available memory levels at or below which SIGTERM or SIGKILL
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signals are sent. The signal will be sent if MemAvailable and
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SwapFree (in /proc/meminfo) at the same time will drop below the
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corresponding values. Can be specified in % (percent) and M (MiB).
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Valid values are floating-point numbers from the range [0; 100] %.
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MemAvailable levels.
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mem_min_sigterm = 10 %
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mem_min_sigkill = 5 %
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SwapFree levels.
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swap_min_sigterm = 10 %
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swap_min_sigkill = 5 %
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Specifying the total share of zram in memory, if exceeded the
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corresponding signals are sent. As the share of zram in memory
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increases, it may fall responsiveness of the system. 90 % is a
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usual hang level, not recommended to set very high.
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Can be specified in % and M. Valid values are floating-point
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numbers from the range [0; 90] %.
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zram_max_sigterm = 50 %
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zram_max_sigkill = 55 %
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#####################################################################
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2. Response on PSI memory metrics (it needs Linux 4.20 and up)
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About PSI:
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https://facebookmicrosites.github.io/psi/
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Disabled by default (ignore_psi = True).
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ignore_psi = True
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Choose a path to PSI file.
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By default it monitors system-wide file: /proc/pressure/memory
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You also can set file to monitor one cgroup slice.
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For example:
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psi_path = /sys/fs/cgroup/unified/user.slice/memory.pressure
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psi_path = /sys/fs/cgroup/unified/system.slice/memory.pressure
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psi_path = /sys/fs/cgroup/unified/system.slice/foo.service/memory.pressure
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Execute the command
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find /sys/fs/cgroup | grep -P "memory\.pressure$"
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to find available memory.pressue files (except /proc/pressure/memory).
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psi_path = /proc/pressure/memory
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Valid psi_metrics are:
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some_avg10
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some_avg60
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some_avg300
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full_avg10
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full_avg60
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full_avg300
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some_avg10 is most sensitive.
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psi_metrics = some_avg10
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sigterm_psi_threshold = 80
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sigkill_psi_threshold = 90
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psi_post_action_delay = 60
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#####################################################################
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3. The frequency of checking the amount of available memory
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(and CPU usage)
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Coefficients that affect the intensity of monitoring. Reducing
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the coefficients can reduce CPU usage and increase the periods
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between memory checks.
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Why three coefficients instead of one? Because the swap fill rate
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is usually lower than the RAM fill rate.
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It is possible to set a lower intensity of monitoring for swap
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without compromising to prevent OOM and thus reduce the CPU load.
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Default values are well for desktop. On servers without rapid
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fluctuations in memory levels the values can be reduced.
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Valid values are positive floating-point numbers.
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rate_mem = 4000
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rate_swap = 1500
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rate_zram = 500
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See also https://github.com/rfjakob/earlyoom/issues/61
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max_sleep_time = 3
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min_sleep_time = 0.1
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#####################################################################
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4. The prevention of killing innocent victims
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Valid values are integers from the range [0; 1000].
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min_badness = 20
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Valid values are non-negative floating-point numbers.
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min_delay_after_sigterm = 0.2
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min_delay_after_sigkill = 1
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Enabling the option requires root privileges.
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Valid values are True and False.
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Values are case sensitive.
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decrease_oom_score_adj = False
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Valid values are integers from the range [0; 1000].
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oom_score_adj_max = 20
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#####################################################################
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5. Impact on the badness of processes via matching their names,
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cmdlines or UIDs with regular expressions using re.search().
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See https://en.wikipedia.org/wiki/Regular_expression and
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https://en.wikipedia.org/wiki/Perl_Compatible_Regular_Expressions
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Enabling this options slows down the search for the victim
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because the names, cmdlines or UIDs of all processes
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(except init and kthreads) are compared with the
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specified regex patterns (in fact slowing down is caused by
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reading all /proc/*/cmdline and /proc/*/status files).
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Use script `oom-sort` from nohang package to view
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names, cmdlines and UIDs of processes.
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5.1 Matching process names with RE patterns
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Valid values are True and False.
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regex_matching = False
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Syntax:
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@PROCESSNAME_RE badness_adj /// RE_pattern
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New badness value will be += badness_adj
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It is possible to compare multiple patterns
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with different badness_adj values.
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Example:
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@PROCESSNAME_RE -100 /// ^Xorg$
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@PROCESSNAME_RE -500 /// ^sshd$
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5.2 Matching cmdlines with RE patterns
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A good option that allows fine adjustment.
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re_match_cmdline = False
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@CMDLINE_RE 300 /// -childID|--type=renderer
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@CMDLINE_RE -200 /// ^/usr/lib/virtualbox
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5.3 Matching UIDs with RE patterns
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The most slow option
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re_match_uid = False
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@UID_RE -100 /// ^0$
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5.4 Matching CGroup-line with RE patterns
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re_match_cgroup = True
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@CGROUP_RE -50 /// system.slice
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@CGROUP_RE 50 /// foo.service
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@CGROUP_RE 2000 /// user.slice
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5.5 Matching realpath with RE patterns
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re_match_realpath = False
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@REALPATH_RE 20 /// ^/usr/bin/foo
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Note that you can control badness also via systemd units via OOMScoreAdjust, see
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https://www.freedesktop.org/software/systemd/man/systemd.exec.html#OOMScoreAdjust=
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#####################################################################
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6. The execution of a specific command instead of sending the
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SIGTERM signal.
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For processes with a specific name you can specify a command to
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run instead of sending the SIGTERM signal.
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For example, if the process is running as a daemon, you can run
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the restart command instead of sending SIGTERM.
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Valid values are True and False.
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execute_the_command = False
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The length of the process name can't exceed 15 characters.
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The syntax is as follows: lines starting with keyword $ETC are
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considered as the lines containing names of processes and
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corresponding commands. After a name of process the triple slash
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(///) follows. And then follows the command that will be
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executed if the specified process is selected as a victim. The
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ampersand (&) at the end of the command will allow nohang to
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continue runing without waiting for the end of the command
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execution.
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For example:
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$ETC mysqld /// systemctl restart mariadb.service &
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$ETC php-fpm7.0 /// systemctl restart php7.0-fpm.service
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If command will contain $PID pattern, this template ($PID) will
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be replaced by PID of process which name match with RE pattern.
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Exmple:
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$ETC bash /// kill -KILL $PID
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It is way to send any signal instead of SIGTERM.
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(run `kill -L` to see list of all signals)
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Also $NAME will be replaced by process name.
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$ETC bash /// kill -9 $PID
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$ETC firefox-esr /// kill -SEGV $PID
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$ETC tail /// kill -9 $PID
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$ETC apache2 /// systemctl restart apache2
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#####################################################################
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7. GUI notifications:
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- OOM prevention results and
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- low memory warnings
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gui_notifications = True
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Enable GUI notifications about the low level of available memory.
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Valid values are True and False.
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gui_low_memory_warnings = True
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Execute the command instead of sending GUI notifications if the value is
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not empty line. For example:
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warning_exe = cat /proc/meminfo &
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warning_exe =
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Can be specified in % (percent) and M (MiB).
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Valid values are floating-point numbers from the range [0; 100] %.
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mem_min_warnings = 25 %
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swap_min_warnings = 25 %
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zram_max_warnings = 40 %
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Valid values are floating-point numbers from the range [1; 300].
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min_time_between_warnings = 15
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Ampersands (&) will be replaced with asterisks (*) in process
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names and in commands.
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#####################################################################
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8. Verbosity
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Display the configuration when the program starts.
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Valid values are True and False.
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print_config = False
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Print memory check results.
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Valid values are True and False.
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print_mem_check_results = False
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min_mem_report_interval = 60
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Print sleep periods between memory checks.
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Valid values are True and False.
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print_sleep_periods = False
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print_total_stat = True
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print_proc_table = True
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print_victim_info = True
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max_ancestry_depth = 1
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separate_log = False
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psi_debug = False
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#####################################################################
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9. Misc
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max_post_sigterm_victim_lifetime = 10
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post_kill_exe =
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forbid_negative_badness = True
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