RPI3 swap experiments (r338342 with vm.pageout_oom_seq="1024" and 6 GB swap)

[Trev]

bob prohaska wrote on 15/09/2018 15:08:
> There were many spurious "indefinite wait" and [...] warnings on the console,

Those warnings are not actually spurious, rather indicative of 
significant i/o delays:

https://www.freebsd.org/doc/en/books/faq/troubleshoot.html#idp59131080

What does the error swap_pager: indefinite wait buffer: mean?

This means that a process is trying to page memory to disk, and the page 
attempt has hung trying to access the disk for more than 20 seconds. It 
might be caused by bad blocks on the disk drive, disk wiring, cables, or 
any other disk I/O-related hardware. If the drive itself is bad, disk 
errors will appear in /var/log/messages and in the output of dmesg. 
Otherwise, check the cables and connections.