More RAM than MemTotal

[Orna Agmon Ben-Yehuda]

Hello Linuxers,

I am missing 180MB, and would like to know where they are. The problem
really interests me in the context of virtual machines, but it also exists
on my laptop  (bare metal installation).
The size depends on the installation: on my laptop180MB are missing, in two
virtual machine images the numbers are 134 and 384.
The difference is between the RAM I know I physically have (or that I know
KVM was told to allocate the VM):

ladypine at alice:~/phd/c/moc$ grep RAM /var/log/kern.log
Mar 26 10:24:45 alice kernel: [34324.028293] 1048576 pages RAM

This is exactly 4G, since each page is 4k: 1048576*4/1024=4096.

and the total memory that /proc/meminfo and top think the system has:

ladypine at alice:~/phd/c/moc$ grep MemTotal /proc/meminfo
MemTotal:        4009628 kB

which is a bit less: 4009628/1024=3915.65

and the gap is:
4096-4009628/1024=180.35

So: 180Mb lost, a reward for an honest finder?

-- 
Orna Agmon Ben-Yehuda.
http://ladypine.org
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