Excluding Process

[alfie-13]

Hi, I'm new to nohang and found it useful in our rhel8 environment. Is it possible to exclude some process to not to be killed by nohang? How can I do that?

[hakavlad]

Hi! You can change the priorities of processes when nohang select them as a victim.

See https://github.com/hakavlad/nohang/blob/v0.2.0/conf/nohang/nohang.conf.in#L189C5-L189C66

Edit the section 7. Customize victim selection: adjusting badness of processes in /etc/nohang/nohang.conf.

For example, prevent the termination of processes containing fooservice in the cgroup2 path:

@BADNESS_ADJ_RE_CGROUP_V2  -1000 /// fooservice

The same by name:

@BADNESS_ADJ_RE_NAME -1000 /// fooname

The configuration file contains examples. Just add the appropriate line to the configuration file and restart nohang.service.

[alfie-13]

thanks @hakavlad so is this the right format if I wanted to exclude the calibre tool?

@BADNESS_ADJ_RE_NAME -1000 /// calibre

Also, what does -1000 do?

[hakavlad]

is this the right format if I wanted to exclude the calibre tool?

Maybe not. For example, on my Debian, its name is GUIPool:

$ oom-sort -l40
oom_score oom_score_adj   UID     PID Name            VmRSS   VmSwap   cmdline
--------- ------------- ----- ------- --------------- ------- -------- -------
      822           233  1000  744337 Web Content        75 M      0 M /usr/lib/firefox-esr/firefox-esr -conten
      822           233  1000  744339 Web Content        75 M      0 M /usr/lib/firefox-esr/firefox-esr -conten
      822           233  1000  744344 Web Content        75 M      0 M /usr/lib/firefox-esr/firefox-esr -conten
      781           167  1000  741228 Isolated Web Co   321 M      0 M /usr/lib/firefox-esr/firefox-esr -conten
      780           167  1000  635548 Isolated Web Co   172 M     11 M /usr/lib/firefox-esr/firefox-esr -conten
      780           167  1000  635552 Isolated Web Co   230 M     10 M /usr/lib/firefox-esr/firefox-esr -conten
      780           167  1000  683991 Isolated Web Co   195 M      0 M /usr/lib/firefox-esr/firefox-esr -conten
      780           167  1000  744006 Isolated Web Co   180 M      0 M /usr/lib/firefox-esr/firefox-esr -conten
      779           167  1000  635523 Privileged Cont   146 M      5 M /usr/lib/firefox-esr/firefox-esr -conten
      779           167  1000  635555 Isolated Web Co   123 M     19 M /usr/lib/firefox-esr/firefox-esr -conten
      779           167  1000  635566 Isolated Web Co   142 M     11 M /usr/lib/firefox-esr/firefox-esr -conten
      779           167  1000  683581 Isolated Web Co   132 M      0 M /usr/lib/firefox-esr/firefox-esr -conten
      779           167  1000  683629 Isolated Web Co   119 M      0 M /usr/lib/firefox-esr/firefox-esr -conten
      779           167  1000  684096 Isolated Web Co   144 M      0 M /usr/lib/firefox-esr/firefox-esr -conten
      779           167  1000  694204 Isolated Web Co   126 M      0 M /usr/lib/firefox-esr/firefox-esr -conten
      779           167  1000  696824 Isolated Web Co   138 M      0 M /usr/lib/firefox-esr/firefox-esr -conten
      779           167  1000  699282 Isolated Web Co   119 M      0 M /usr/lib/firefox-esr/firefox-esr -conten
      779           167  1000  744237 Isolated Web Co   165 M      0 M /usr/lib/firefox-esr/firefox-esr -conten
      779           167  1000  744275 Isolated Web Co   173 M      0 M /usr/lib/firefox-esr/firefox-esr -conten
      778           167  1000  635580 Isolated Web Co    98 M      9 M /usr/lib/firefox-esr/firefox-esr -conten
      778           167  1000  635590 Isolated Web Co   100 M     10 M /usr/lib/firefox-esr/firefox-esr -conten
      778           167  1000  635609 Isolated Web Co   101 M     11 M /usr/lib/firefox-esr/firefox-esr -conten
      778           167  1000  635627 Isolated Web Co   107 M      7 M /usr/lib/firefox-esr/firefox-esr -conten
      778           167  1000  664285 Isolated Web Co   108 M      0 M /usr/lib/firefox-esr/firefox-esr -conten
      778           167  1000  683951 Isolated Web Co   108 M      0 M /usr/lib/firefox-esr/firefox-esr -conten
      735           100  1000  635500 WebExtensions     194 M      7 M /usr/lib/firefox-esr/firefox-esr -conten
      735           100  1000  740901 Isolated Web Co   206 M      0 M /usr/lib/firefox-esr/firefox-esr -conten
      734           100  1000  683565 Isolated Web Co   138 M      0 M /usr/lib/firefox-esr/firefox-esr -conten
      684             0  1000  635305 firefox-esr      1495 M    129 M /usr/lib/firefox-esr/firefox-esr -P
      669             0  1000  747845 GUIPool           248 M      0 M /usr/bin/python3.9 /usr/bin/calibre

I'll give more explanation later.