mmap-sandbox

THIS COMES WITH NO WARRANTY OF ANY KIND - NOR IS IT OFFICIALLY ENDORSED OR SUPPORTED BY MONGODB INC, MONGODB LTD.

It contains source taken from the MongoDB open source project so like that is AGPL licensed. see https://github.com/mongodb/mongo/blob/master/GNU-AGPL-3.0.txt

Create the source file:

dd if=/dev/zero of=/tmp/1GB bs=1073741824 count=1

Compile:

g++ mmap.cpp -o mmap

Run:

Best run in a VM with 2GB memory (adjust memory and/or filesize)

# drop filesystem cache

echo 3 | sudo tee /proc/sys/vm/drop_caches

./mmap

Choose an option to perform the task. A confirmation message will appear in each case - hit enter again to proceed.

General steps:

1. load the shared view

2. load the private view

3. start experimenting with reading/writing either view, copying private -> shared, remapping the private view, etc

Interesting things to note:

while true; do ps aux | grep mmap | grep -v grep; done

top -p $PID_OF_MMAP

free -m -s 0.5