Is maximum swap usage tunable?

[Mike]

On 2/28/2018 12:03 PM, bob prohaska wrote:
> In watching system compilations on an RPi3 it looks as if the
> system starts killing processes with "out of swap" warnings 
> well below 50% of full utilization (in this case, 2 GB). One
> recent instance of make -j4 kernel-toolchain killed llvm-tblgen
> with only 34% of the swap in use.
> 
> Is the maximum swap usage limit adjustable in any way? I didn't
> recognize anything useful in the page at
> https://www.freebsd.org/cgi/man.cgi?query=sysctl(8)&sektion=&manpath=freebsd-release-ports 
> 
> It's possible the problem is really swap speed, rather than size, so I'd
> like to try changing size limits if possible. The swap media claims 2-3 
> MB/sec random write speed and observations with gstat seem to support the
> claim, but transient stalls are hard to observe. An RPi2 with similar 
> hardware seems to have no problems.
> 


> It's possible the problem is really swap speed

I was running into swap speed / timeout issues.  There were messages on
the console to that effect.

Once I put the swap space on rotating rust, that part of the compile
problem disappeared.  I use 1GB swap space.

YMMV.