Bug ID 1926989: BIG-IP Virtual Edition: kswapd running constantly and consuming most of the CPU cycles of a core

Last Modified: Jun 28, 2025

Affected Product(s):
BIG-IP Install/Upgrade, TMOS(all modules)

Known Affected Versions:
17.5.0

Fixed In:
17.5.1

Opened: Apr 14, 2025

Severity: 2-Critical

Symptoms

After a new installation or after an upgrade to of a Virtual Edition to one of the affected versions, the 'kswapd' daemon runs constantly, consuming up to 100% of the cycles of a CPU core.

Impact

A CPU core constantly consuming most of its CPU cycles. General slowness of the system.

Conditions

- installation of a new BIG-IP Virtual Edition or - upgrade of a BIG-IP Virtual Edition to one of the affected versions

Workaround

If the problem is present after a TMOS upgrade: - check what was the value of vm.min_free_kbytes before the upgrade by booting back in the previous volume - set the same value in the new volume with the command: # sysctl -w vm.min_free_kbytes=<VALUE> No reboot or tmm restart is needed. If the Virtual Edition is a fresh install: - set the vm.min_free_kbytes value to 24141 # sysctl -w vm.min_free_kbytes=24141 No reboot or tmm restart is needed. You may need to follow the "Additional Information" section in https://my.f5.com/manage/s/article/K000150960 to ensure that the changes persist after a reboot.

Fix Information

Vm.min_free_kbytes is given the correct value.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips