Strange ARC/Swap/CPU on yesterday's -CURRENT

[bob prohaska]

On Sun, Mar 11, 2018 at 10:43:58AM -1000, Jeff Roberson wrote:

> Also, if you could try going back to r328953 or r326346 and let me know if 
> the problem exists in either.  That would be very helpful.  If anyone is 

Not sure this is relevant, but r326343 is able to run a j4 buildworld
to completion on an RPi3 with 3 gigs of microSD-based swap. There are
periods of seeming distress at times (lots of swread, pfault state
in top along with high %idle) in top, but the compilation completes.

In contrast, r328953 could not complete buildworld using -j4. Buildworld
would stop, usually reporting c++ killed, apparently for want of swap,
even though swap usage never exceeded about 30% accoring to top.

The machine employs UFS filesystems, the kernel config can be seen at

http://www.zefox.net/~fbsd/rpi3/kernel_config/ZEFOX

Thanks for reading, I hope it's useful.

bob prohaska