Just ran across this on one of my firewall appliances.
Approaching the limit on PV entries, consider increasing either the vm.pmap.shpgperproc or the vm.pmap.pv_entries tunable.
What exactly is a "PV" entry? No one said.
This firewall has been running for 840 days and just started dropping some phonecalls for the site this week, so i am just going to reboot it and see if this error goes away. But it would be interesting to know what exactly this error message indicates. What can cause this behaviour?
From this article here: https://supportportal.juniper.net/s/article/EX2300-C-printing-logs-Approaching-the-limit-on-PV-entries?language=en_US
Seems to have something to do with virtual memory.
On the kernel, each virtual address which is mapped to a given dynamically-allocated physical memory page uses up one pv_entry in the kernel, which contains information about that specific virtual translation. The kernel imposes a max limit on the number of pv entries that can be allocated on the system.
This message means the system is running low on pv entries in the kernel,
will post back if rebooting fixes it.
device is an SG-3100 running 21.05.2-RELEASE