What's the meaning of this warn?

[Lowell Gilbert]

Jason <lisen1001 at gmail.com> writes:

> HI,ALL:
>
> My freebsd server offer service to thousands of clients.
> I found lots of warning in the /var/log/message like this :"Approaching
> the limit on PV entries, consider increasing either the
> vm.pmap.shpgperproc or the vm.pmap.pv_entry_max tunable"
>
> My question is :
> 1.what is the meaning of PV?

Physical-to-Virtual mappings.

> 2.Although there are lots of this warning,my server works still well.
> Could someone explain the meaning of this warning ?

With thousands of people running the same programs, there will be a lot
of mappings for the memory pages containing the programs themselves, the
libraries they use, and so on.  As long as you're not running out of
memory in general, you might get better performance by having more
pv_entry structures available in the system.