Database servers consuming swap instead of page cache

Hello,

We have a number of Oracle Linux 8.3 database servers (Oracle 12c) where swap is overtime getting more and more consumed, but we don't see page cache being released when there is the need for memory.

Some serves were configured for Oracle 12c using "oracle-rdbms-server-12cR1-preinstall-1.0-7" others were configured using tuned's "oracle" profile. The behavior is basically the same, no matter the configuration method. (We have Huges Pages configured for all servers, by the way.)

We have been trying to play with reducing "vm.swappines", but it's not making a difference. We see pcp-pmie reporting "Severe demand for real memory xxxpgsout/s" on syslog but, again, instead of seeing page cache being freed up we see swap being consumed.