# VM PMAP Errors



## qwaven (Jul 6, 2010)

Hello,

Had a power failure which seems to have caused some errors to start appearing on a FreeBSD system. The system appeared to be running fine before the power failure.

I've done a lot of searching around, including on this forum, but have not been able to find a cause for the errors or how they can be resolved.

I've tried upgrading from 8.1-RC1 to 8.1-RC2 but this did not seem to help.

The error I see:


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

Mine are:

```
sysctl vm.pmap.shpgperproc: 200

sysctl vm.pmap.pv_entry_max: 1744512
```

I have also set the below but did not appear to help.


```
sysctl kern.ipc.shm_use_phys=1
```

Also note the PMAP values do not appear to change. (autotune)


Any help with figuring out what is wrong would be great. I believe something must have "broke" from the power failure as I did not see this prior. However I do not know much about "PMAP" values to really determine anything of use.

System is running as a squid proxy/dansguardian system.

Thanks a lot for your help!


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## qwaven (Jul 7, 2010)

Perhaps someone can help with understanding why the sysctl "vm.pmap.shpgperproc" is "read only". I have noticed when I try and set this manually. How can this be changed?

Thanks!


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## qwaven (Jul 8, 2010)

Anybody?


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## t1066 (Jul 9, 2010)

If it is read only, you have to change the value in loader.conf and reboot.


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## qwaven (Jul 9, 2010)

Thanks for your reply t1066,

I had actually tried that and for some reason the settings would still not stick.

i have now tried compiling a new kernel with the option:


```
options PMAP_SHPGPERPROC=XXXX

where XXXX is my desired value
```

This seems to have worked and I have not received any more errors. 

Thanks!


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