Re: where is my memory?

[Steven Bellovin <smb%cs.columbia.edu@localhost>]

On Sep 21, 2010, at 5:51 34PM, matthew sporleder wrote:

> On Tue, Sep 21, 2010 at 5:38 PM, Matthew Mondor
> <mm_lists%pulsar-zone.net@localhost> wrote:
>> On Sun, 19 Sep 2010 15:13:59 -0400
>> matthew sporleder <msporleder%gmail.com@localhost> wrote:
>> 
>>> So I've recently been exploring a pretty common mystery on netbsd
>>> machines- where is my memory?
>> 
>> I'm not sure this answers your questions, but the dmesg of a system
>> here (also with 2GB RAM) has:
>> 
>> total memory = 2047 MB
>> avail memory = 1999 MB
>> 
>> I assume some pages are reserved and/or used for PMMU tables, etc...
>> --
>> Matt
>> 
> 
> total memory = 256 MB
> avail memory = 239 MB
> 
> So that works well with the vmstat -s numbers.  However, that still
> doesn't really explain where that memory is.
> 
> I guess top should be patched or something to reflect the vmstat -s
> numbers instead of whatever it's currently using.
> 
> Would you mind looking at vmstat -s and see if you're missing 48MB?

Some graphics chips, especially on lower-end machines, use main memory, thus 
making it unavailable to the CPU.

                --Steve Bellovin, http://www.cs.columbia.edu/~smb