#StackBounty: #memory #numa Memory distribution in NUMA nodes does not add up to system memory

Bounty: 50

I recently started working on systems with NUMA nodes, and noticed something strange.

/proc/meminfo shows the sytem has 128461 MB

[root@nfvis node]# head -n4 /proc/meminfo
MemTotal: 131544388 kB
MemFree: 334016 kB
MemAvailable: 49968 kB
Buffers: 4296 kB

The system has two NUMA nodes, and here’s memory distribution across the nodes:

[root@nfvis node]# head -n4 node0/meminfo
Node 0 MemTotal: 66751388 kB
Node 0 MemFree: 308952 kB
Node 0 MemUsed: 66442436 kB
Node 0 Active: 309552 kB

[root@nfvis node]# head -n4 node1/meminfo
Node 1 MemTotal: 67108864 kB
Node 1 MemFree: 22872 kB
Node 1 MemUsed: 67085992 kB
Node 1 Active: 0 kB

Clearly node0 shows 65186 MB and node1 shows 65536 MB, which adds up to 130722 MB. I am not able to understand how the system lost 2261 MB memory.
It would be really helpful if someone could point me in right direction.

Get this bounty!!!

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