This is a demo/test program for a proposed dm event mechanism using poll().
Steps:
- Build and boot a kernel with the poll DM event patches
- install device-mapper-devel.
- compile this program with
make - Set up some dm devices that might generate an event, such as a thin LV on a massively-underprovisioned thinpool
- run this
- start using the thin LV, it should generate a low-water event, and this should tell you that and print its status