opensmtpd-filter-dkimsign: high memory usage

Hi,

I am running an OpenSMTPD server with opensmtpd-filter-dkimsign-0.5p2 on OpenBSD 7.4 (amd64). I noticed recently that the dkimsign program was using a lot of memory:

$ ps ax -orss,command | grep dkimsign
110920 /usr/local/libexec/smtpd/filter-dkimsign -d wsb.onl -s viper1 -k /etc/mai
304 grep dkimsign

I am not a C programmer so maybe I am wrong, but it seems to me that over 100 MB is a lot for the simple program.

And of course the relevant line in my smtpd.conf is the following:

filter "dkimsign" proc-exec "filter-dkimsign -d wsb.onl -s viper1 \
-k /etc/mail/dkim/private.key" user _dkimsign group _dkimsign

I am not sure if this memory usage is related to how long the program is being ran (server's uptime is over 100 days), so I didn't restart the dkimsign program to investigate. But I will be happy to provide more information if needed.

Thanks,
--
Songbo Wang