vm.pmap.shpgperproc syslog messages

[D Hill]

I just noticed today I'm starting to get messages in ../messages stating:

   Approaching the limit on PV entries, consider increasing either the
   vm.pmap.shpgperproc or the vm.pmap.pv_entry_max sysctl.

I did some searching and don't really know what is going on. I did a 
search using sysctl for all pmap knobs and this is what they are 
currently:

   vm.pmap.pmap_collect_active: 0
   vm.pmap.pmap_collect_inactive: 0
   vm.pmap.pv_entry_spare: 51310
   vm.pmap.pv_entry_allocs: 67575721858
   vm.pmap.pv_entry_frees: 67574088800
   vm.pmap.pc_chunk_tryfail: 0
   vm.pmap.pc_chunk_frees: 416252902
   vm.pmap.pc_chunk_allocs: 416262928
   vm.pmap.pc_chunk_count: 10026
   vm.pmap.pv_entry_count: 1633059
   vm.pmap.shpgperproc: 500
   vm.pmap.pv_entry_max: 6125408

I did increased vm.pmap.shpgperproc to 500 from 200 and immediately saw 
vm.pmap.pv_entry_max increase as well.

This server is a Dell PowerEdge 6850 with four 3.0Gz dual core Zeon 
processors and 12Gb ram. The server's only purpose is a spam filter. It is 
running SpamAssassin, ClamAV, Postfix and MySQL. The server is pretty 
memory intensive. Active memory usually doesn't drop below 8Gb. 
SpamAssassin usually has roughly 24 children running all the time 
consuming ~120Mb per child. MySQL is currently taking ~5.5Gb.

Can someone shed light on what is going on or what needs to be tweaked?

-d