Here too works without reboot. But what I wanted to say that it went from absolutely NO ads whatsoever in MM to lots of ads under Oreo overnight. It struck me as I thought installing Adaway would help me get rid of the ads all the way with no special user intervention like it did under MM. (Btw I had no special user added host entries).
I don't have it set to auto update but i tried updating (and rebooting) when I noticed the ads but it didn't do the trick.
Its a fairly simple test to check if Adaway itself is working.
1. make a copy of the AdAway generated hosts file onto your SDCard.
2. Turn off adaway / re-enable your default host file
3. Open the AdAway host file that you had backed up
4. Now try pinging a host name from your the backed up AdAway hosts file
5. Some of them may not ping anyway, but as you move down the list, one will actually ping back (other than 127.0.0.1 or 0.0.0.0, if you do negt this you have not done the steps above correctly, or see step 10). Remember that host name
6. Re-open Adaway and download the hosts
7. Search for the host that you got above in your new hostfile, If you don't find it, go back to step step 1
8. Now try pinging the host that you found in the backup host file, and the new host file
9. If it does not ping back or pings back 127.0.0.1 or 0.0.0.0, your AdAway / host file is working, and its your host file sources list that is lacking if you see ads elsewhere, not AdAway.
10. If it does ping back and it IS in your latest host file, then look back at the other response as to why your host file is being ignored
When comparing MM and Oreo, these are separated by time, and the ad hosters are getting wise to host based Ad blockers and/or your list sources. ie you also need to get more aggressive / wiser to match or beat them at their game. If you have the default host sources, you probably only have 4 or so, I personally have about 30 and last I checked, crDroid Oreo has something like 10 by default.